Faxitron MX-20 Reverse engineering (with some good results) - Page 1
Forum section: electronics / general

author: kilohercas
author_rank: Regular Contributor
timestamp: January 13, 2018, 07:11:19 pm
content: I started to make my own electronics for Faxitron MX-20 Machine. I only get electronics, X-Ray generator and X-Ray sensor, so I have to put something inside my won box.I don't have software of any kind, so i have to write my own. First step was to make USB Hub, one channel wil go to sensor, second channel to FT2232H Controller as UART ( and second IC channels goes to stepper drivers forCBCTturning table)After that, i had to write my own software for Hamamatsu 12x12 X-Ray sensor. That was quite a difficult task, but i was able to make it happen. I was able to do that in Visual Basic, it uses generic Hamamatsu DCAM-API DLL inside system32 (when you install drivers)Operation is simple. Connect USB to HUB, it detects if FT2232H and C9732DK-11, after that, you wait for 60s warmup ( x ray tube or something, timer is inside x ray controller ) And you just set time and kV, and press take a picture. It automatically sends command to enable x ray source, you should (2.5s is ramp-up to 35kV, only at this point x ray is stable based on sense output on x ray tube)put into remote mode: (do this first !!!!)Dim mx20(5) As Byte 'mx20(0) = &H21mx20(1) = &H4Dmx20(2) = &H52mx20(3) = &HDPORT.Write(mx20, 0, 4)This is how you set exp time and voltage:mx20(0) = &H21mx20(1) = &H54mx20(2) = &H30 + Fix(NumericUpDown1.Value / 100)' time 0.1 to 999.9mx20(3) = &H30 + Fix(NumericUpDown1.Value / 10) Mod 10mx20(4) = &H30 + Fix(NumericUpDown1.Value) Mod 10mx20(5) = &H30 + ((NumericUpDown1.Value * 10) Mod 10)mx20(6) = &HDUART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 7, BW)Sleep(100)mx20(0) = &H21mx20(1) = &H56mx20(2) = &H30 + Fix(NumericUpDown2.Value / 10) ' Voltage 10-35mx20(3) = &H30 + NumericUpDown2.Value Mod 10mx20(4) = &HD 'Enabling X-Ray source via UART message is also easy, just few special characters: '0x21+0x42+0x0D and after short delay 0x43mx20(0) = &H21mx20(1) = &H42mx20(2) = &HDUART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 3, BW)Sleep(50) ' 50ms Delaymx20(0) = &H43UART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 1, BW)It was so bad design to put 500W power supply, it even needs load to work. That is madness. All you need is isolated 24V 1A for x ray ( it is uses all interlocks, and is enabled by relay on J7 connector )12V 1.3A (main electronics)-12V 0.05A (opamps +RS232 ?)5V 0.5A (MCU electronics)5V 5A (Hamamatsu sensor)Now, controller electronics looks old, and very complicated. Since i will be using computer, it would be better just connect x ray head to my own electronics, so i spend all tay figuring out controller connector to x ray source.It is IDC20, and it has control, sense and other signals prescient, just have to figure out what is what.IDC20 pins 1,2,3,4,12,13 are connected to opamp outputs inside x-ray head electronics. I only understand that 12pin is kV sense output to MCU board (1v=10kV), and 3pin is I sense, or it looks like this, with transfer function of:10kV-> 0.208mA -> 0.61V15kV-> 0.201mA -> 0.90V20kV-> 0.192mA -> 1.19V25kV-> 0.183mA -> 1.46V30kV-> 0.175mA -> 1.76V10kV-> 0.165mA -> 2.05VIDC20 10PIN is also strange, MCU is supplying voltage, with a transfer function of ( every time, not only when x-ray is on)10kV = 1.330V20kV = 2.333V30kV = 3.116V35kV = 3.548VUpdate: It has something to do with focusing. disconnecting yield blurry images. Maybe could be tuned separately for better picture, so must keep on DAC.For output that change state when x ray is on, i have few of them:PIN5 is connected to MCU via 330R resistor ( mcu supplying 5V when enabling x ray )PIN7 is connected to MCU via 2k2 resistor ( mcu supplying 5V when enabling x ray , another 12V relay for 24V that is main power for HV supply)PIN9 is connected to DAC that supplying setpoint voltage from 1V (10kV) to 3.5V (35kV ) again, only when x-ray is on.PIN11 is connected to DAC, it is supplying 2.7V only when x-ray is on (no mater on set voltage or time)PIN10 looks like getting 10V from x-ray head, it is connected to potentiometer top input on high voltage power supply. still need to figure out why.PIN15 and PIN17 is unconnected ( hooray:) )PIN 14, PIN18, PIN19, and PIN20 are groundNow I have to try to make my own driver on simple PCB, and we will see how it works. This will enable to buy MX-20 systems on ebay, and just ask to send sensor and x ray source, and i will be able to control everythingThis post is mainly to remind myself, what i did so i don't loose it

author: eliocor
author_rank: Unknown
timestamp: January 15, 2018, 01:21:55 am
content: What software will you use/are you using for CBTC (Cone beam computed tomography) ?

author: kilohercas
author_rank: Regular Contributor
timestamp: January 15, 2018, 05:35:44 am
content: MATLAB.But it also would be fun to write my own in C/vb

author: kilohercas
author_rank: Regular Contributor
timestamp: February 12, 2018, 10:23:00 am
content: few weeks of hard work, and i have complete solution for reading data from sensor as well as controlling x ray tube with my own driver that is based on Intel max10 fpga, works like a charm

author: jeremy
author_rank: Super Contributor
timestamp: February 12, 2018, 02:28:38 pm
content: Very cool!

author: kilohercas
author_rank: Regular Contributor
timestamp: February 13, 2018, 05:30:29 am
content: https://youtu.be/HrUNLFlLzzU

author: jeremy
author_rank: Super Contributor
timestamp: February 13, 2018, 05:44:29 am
content: What was the USB hub for? I couldn’t quite tell. I know you have an FTDI, but what else?Also, is there any reason you decided to use an FPGA over a micro?Would love to know more about how the panel outputs data and in what format.Edit: ah I see now, the detector is USB connected.

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 06:30:27 am
content: Awesome work, would love to hear more.My MX-20 has the older RadEye sensors, so I had to do a lot more work to get data out of them. I would very much like to make my software talk to the control panel. I don't understand what you mean here:mx20(0) = &H21mx20(1) = &H42mx20(2) = &HDUART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 3, BW)Sleep(50) ' 50ms Delaymx20(0) = &H43UART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 1, BW)Are these instructions interpreted by your firmware, or passed to the Faxitron's controller? If they're handed off to the Faxitron and processed there, how do you connect your controller to the Faxitron's CPU?I don't currently have a UART available via the USB connection to my digitizer, but I could add one easily enough, if I knew where to connect it to the Faxitron.

author: kilohercas
author_rank: Regular Contributor
timestamp: February 13, 2018, 09:14:25 am
content: Quote from: KE5FX on February 13, 2018, 06:30:27 amUART is connected to faxitron controller, this series of commands will trigger x ray source for fixed amount of timeI made project in hackaday.iohttps://hackaday.io/project/52104-x-raying-rose-in-30kev-in-high-resolutionyou will be able to find all information about this project, with design files so you can make it yourselfIf you can, please share this video tomorrow, since it since, and it kind a looks beautifulLets make it as viral video for tomorrow

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 09:35:49 am
content: Quote from: kilohercas on February 13, 2018, 09:14:25 amThanks! Looks promising.(Edit, having watched the video, it looks fantastic!)Unfortunately I don't seem to be able to open the .rar files with WinZip -- it says they're invalid. Can you post ordinary .zip files additionally/instead?I would prefer to create a remote-control link to the MX-20's existing control panel, but your work on the new PCB is certainly impressive. Agreed that the power supply they used is ridiculous. Mine has a large wirewound resistor that does nothing but provide the minimum load and dissipate heat.

author: eliocor
author_rank: Unknown
timestamp: February 13, 2018, 09:41:16 am
content: Quoteupdate your WinZip with the latest version...Otherwise go tohttps://www.rarlab.com/download.htmand download WinRar: the archives have no problems at all!!!

author: Mr. Scram
author_rank: Super Contributor
timestamp: February 13, 2018, 09:58:40 am
content: I'd love to get my hands on a tool like that. That looks absolutely amazing and very useful.

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 10:05:37 am
content: Quote from: Mr. Scram on February 13, 2018, 09:58:40 amThat Hamamatsu panel is... enviable.Some zero-feedback scammer is currently trying to sell 10 of them on eBay for $10,000 apiece.Although it sounds like it's limited to <2 second exposure times if I understand the video correctly? With my RadEye sensors I often have to take 20-30 second exposures, but maybe that's not necessary with the C9732DK.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 13, 2018, 10:42:47 am
content: Quote from: KE5FX on February 13, 2018, 10:05:37 amMy Faxitron ( with 50mm Hamamatsu sensor) does up to 15 sec exposures. Not sure if extending would have much benefit due to noise floor. A few more kV would be much more useful.The tube is rated to 50kV, but the sensor datasheet states 35kV max - would be interesting to know what the actual constraints are, as the limited penetrating power is the biggest disappointment of this system.Where does the 2 sec limit come from ?I don't understand the reason for replacing the faxitron control electronics - is there any benefit ?Are you still using the original cabinet or were you re-packaging to reduce size?

author: kilohercas
author_rank: Regular Contributor
timestamp: February 13, 2018, 11:02:26 am
content: Quote from: mikeselectricstuff on February 13, 2018, 10:42:47 amIt comes from sensor, it has double value between 1 and 2. higher exposures are just stitched images made from 2s exposures i think. (DLL takes that data)I only get detector and x ray tube, that's why i am remaking it myself. Also, i have greater control over tube voltage, have diagnostics about tube voltage/current, so i can decide then to take picture, and stop x ray after that. I will also planing to add mechanical shutter, if i will try to x ray my hands, just to get dose down. Same goes for stepper control and other automation. this is very powerful system now, i even can think about chaining sensor position with other stepper to get different magnificationAlso, electronics are old, if they break, i loose everything, now i know half the system, so less chance of failureIt can work with 100kV. In my work, i get visit from Hamamatsu, he says that problem with energy and power is that CsI will get yellow in time, but that's not a problem, since we still have so much data to work with, and we could use higher exposure times to get higher pixel values, so detector will be good for a long time.

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 11:10:14 am
content: Quote from: mikeselectricstuff on February 13, 2018, 10:42:47 amI was able to crank the HV trimmer up to get 37.015 kVp at 325 uA out of mine. The PSU folds back either current or voltage once the total power exceeds 12 watts, which is a good match for the maximum-rating spec of the TruFocus tube.QuoteLinas mentioned on his Hackaday page that the Hamamatsu sensor has "very limited range, only between 1 and 2 seconds of integration."QuoteFrom my own perspective, I'd like to be able to set the voltage and exposure time from the software and trigger it remotely. I often take bracketed exposures at different settings, looking for the best compromise for a given subject. It'd be nice if I didn't have to punch a lot of buttons every few seconds, or keep track of the resulting image settings manually.The original Faxitron software could also carry out automatic calibration exposures, which I'd like to implement in my own software at some point.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 13, 2018, 11:15:46 am
content: Quote from: KE5FX on February 13, 2018, 11:10:14 amYou can do that via the serial interface

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 11:21:14 am
content: Quote from: mikeselectricstuff on February 13, 2018, 11:15:46 amI didn't exactly see any 9-pin RS232 ports on mine.I'm sure the necessary serial lines were brought out to the SCSI-style connector on the rear panel, but that's long gone. Have you run across any documentation for their command set?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 13, 2018, 12:04:04 pm
content: Quote from: KE5FX on February 13, 2018, 11:21:14 amI'm not familar with all the variants - I assumed they all had remote control, but as these units were probably originally designed for film, maybe not.

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 12:43:34 pm
content: Quote from: mikeselectricstuff on February 13, 2018, 12:04:04 pmI'm sure that itcanbe controlled remotely because this particular unit came with its manuals. There is a variant of the usual MAX232 interface IC on the controller board, so it wouldn't be hard to trace its pins through the cable that formerly went to the external connector. But the manuals have no information on how the low-level communication with the PC worked, and disassembling the firmware would consume more time than it'd be worth.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 13, 2018, 01:18:20 pm
content: Quote from: KE5FX on February 13, 2018, 12:43:34 pmA while ago I grabbed a dump of the serial comms - it was pretty simple & obvious ASCII - will see if I can find it

author: KE5FX
author_rank: Super Contributor
timestamp: February 13, 2018, 10:53:30 pm
content: Quote from: mikeselectricstuff on February 13, 2018, 01:18:20 pmThanks, that could come in very handy. I'm mostly interested in starting/stopping the exposure and setting the kVp. The ability to set the exposure time would be good as well, but the PC could emulate that if necessary.

author: kilohercas
author_rank: Regular Contributor
timestamp: February 14, 2018, 05:47:19 am
content: Quote from: KE5FX on February 13, 2018, 10:53:30 pmHave you try to look at the first post ?All of this information is detailed. only stop function is missing...

author: KE5FX
author_rank: Super Contributor
timestamp: February 14, 2018, 06:10:44 am
content: Quote from: kilohercas on February 14, 2018, 05:47:19 amThat doesn't do me any good if I don't use your hardware, does it? I already have a working system that I don't want to change to that extent. I'd just like to be able to send remote commands to the original Faxitron controller.That's basically why I was asking if your serial code was communicating with the original hardware or with your own controller.

author: kilohercas
author_rank: Regular Contributor
timestamp: February 14, 2018, 06:59:15 am
content: Quote from: KE5FX on February 14, 2018, 06:10:44 amput into remote mode: (do this first !!!!)Dim mx20(5) As Byte 'mx20(0) = &H21mx20(1) = &H4Dmx20(2) = &H52mx20(3) = &HDPORT.Write(mx20, 0, 4)This is how you set exp time and voltage:mx20(0) = &H21mx20(1) = &H54mx20(2) = &H30 + Fix(NumericUpDown1.Value / 100)' time 0.1 to 999.9mx20(3) = &H30 + Fix(NumericUpDown1.Value / 10) Mod 10mx20(4) = &H30 + Fix(NumericUpDown1.Value) Mod 10mx20(5) = &H30 + ((NumericUpDown1.Value * 10) Mod 10)mx20(6) = &HDUART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 7, BW)Sleep(100)mx20(0) = &H21mx20(1) = &H56mx20(2) = &H30 + Fix(NumericUpDown2.Value / 10) ' Voltage 10-35mx20(3) = &H30 + NumericUpDown2.Value Mod 10mx20(4) = &HD 'Enabling X-Ray source via UART message is also easy, just few special characters: '0x21+0x42+0x0D and after short delay 0x43mx20(0) = &H21mx20(1) = &H42mx20(2) = &HDUART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 3, BW)Sleep(50) ' 50ms Delaymx20(0) = &H43UART_Status = FT_Write_Bytes(UART_Handle, mx20(0), 1, BW)This is serial to original controller

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 14, 2018, 11:03:47 am
content: From memory I think it's 9600 baud

author: KE5FX
author_rank: Super Contributor
timestamp: February 14, 2018, 11:20:40 am
content: Quote from: kilohercas on February 14, 2018, 06:59:15 amCan I ask where you were providing this data, and at what baud rate (9600, as Mike says?)The MAX202 that's next to the 10-pin port labeled "RS232" doesn't have +5 on its VCC pin by default. I tried applying +5 externally and sending a couple of commands (!MR<cr>and!T1230<cr>) at rates from 110 to 115200, but nothing happened.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 14, 2018, 11:34:04 am
content: Quote from: KE5FX on February 14, 2018, 11:20:40 amCan you post a photo of your controller to see if it's the same as mine - may be some link options or different firmware

author: KE5FX
author_rank: Super Contributor
timestamp: February 14, 2018, 12:00:11 pm
content: Quote from: mikeselectricstuff on February 14, 2018, 11:34:04 amHere's a link to the photo (too big to post in the thread directly):http://www.ke5fx.com/fx_ctrl.jpgThe 27C512 EPROM is labeled "V3.1 MOD", with the checksum 317E. Binary image ishere.There is another chip that looks like a mask-programmed ROM, which is labeled 43805-65202-F SN 4312E-082 MX20 MICROPROS.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 14, 2018, 12:15:07 pm
content: Quote from: KE5FX on February 14, 2018, 12:00:11 pmStrange about the unconnected supply to the 232 transceiver - may be worth seeing if you can trace where it goes to get a clue as to why it's disabled ( a fine wire brush can be useful for this).

author: KE5FX
author_rank: Super Contributor
timestamp: February 15, 2018, 08:15:39 am
content: Quote from: mikeselectricstuff on February 14, 2018, 12:15:07 pmI suspect that it's some kind of factory diagnostic port, given that nothing was originally plugged into it. Ordinarily I would X-ray it to find out where the pins go, but...Contrary to what I said earlier, there actuallywasa 9-pin connector in the digitizer area, connected to J5 on the controller board, but it doesn't have a MAX202 nearby and it doesn't act like an RS-232 port. Pins 3, 4, and 6 are pulled up to +5, with all others low. It appears on theblock diagram in the manualas "Cable A."

author: kilohercas
author_rank: Regular Contributor
timestamp: February 16, 2018, 01:52:11 pm
content: https://youtu.be/T_qmQ1a4ftw

author: Fraser
author_rank: Super Contributor
timestamp: February 26, 2018, 04:45:27 pm
content: KE5FX,The 9 pin connector (cable A) located low down on the rear of the cabinet is the standard RS232 serial communications link to a PC serial port. I have various versions of MX-20 control software but they all expect to find a camera module connected so sadly they will not work for youFraser

author: KE5FX
author_rank: Super Contributor
timestamp: February 26, 2018, 11:17:12 pm
content: If it's a standard port, it certainly doesn't act like one.The path of least resistance in my case will probably be to run some spare I/O lines from the FPGA board to optocouplers across the up/down and time/voltage keys. Just seems like unnecessary hackery, that's all.

author: Fraser
author_rank: Super Contributor
timestamp: February 26, 2018, 11:44:29 pm
content: I think I have the schematics for the control board. If so I will check the serial port design for you.It will have to be tomorrow though.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 12:00:27 am
content: I just had a thought........The early MX-20 Digital with Bioptics camera array is not as highly integrated with the OC in terms of control.From memory the PC controls the camera side of things but only provides monitoring of the safety interlocks, X-Ray on condition and initiatedps X-Ray off. It does not need a complex RS232C control set to achieve such limited monitoring and control. It could even be achieved with just the handshake lines !The later MX-20 design provides much more control over the cabinet from the PC. The PC is able to monitor and set Exposure and Kv as well as control the X-Ray generator. I am uncertain what changes were made to the control PCB but IIRC it had an additional 7 segment LED for the time window for tenths of a second. I both versions of the MX-20 X-Ray head so have the EPROM's if that is all that needs to be changed.Fraser

author: KE5FX
author_rank: Super Contributor
timestamp: February 27, 2018, 01:44:43 am
content: Quote from: Fraser on February 26, 2018, 11:44:29 pmThat would rock, if you can find schematics. Even if your board is different from mine (and it probably is, if you have 0.1-second exposure time resolution) it could still come in very handy in the future.To date, the only connection I've added is a wire from the "X-ray on" LED to an input line on my digitizer board, so that the software can tell when the exposure starts and stops. If I eventually decide to add remote controls to some of the keypad buttons, a schematic could save some hunting and poking, even if it's not the right version.

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 06:59:58 pm
content: OK, I do have schematics for the control board...... of the original film type MX-20 circa 1997.Whilst the controller does have a RS232 port it does not seem to be for remote control as the film cabinet had no need for such (having no PC).Looking at the schematics I can also seen references to a 9 pin AEC sensor D type connector. I will upload the controller schematics but I am wondering........ do you have a Digital era MX-20 or the original film type cabinet that does not have the remote control capability or digital camera in the extended base area ?The film type cabinet did have the uptight of an auto exposure X-Ray sensor that sat under the cabinet chamber and helped the user achieve good exposures of the film.A digital era MX-20 would have the camera option detailed on the cabinets ID label on its rear. There would be a "DC" option type shown.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 07:32:26 pm
content: Schematics for the non digital 1997 Faxitron MX-20......

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 07:34:12 pm
content: Continued

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 07:36:00 pm
content: Continued

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2018, 07:38:20 pm
content: Last pictures for now

author: KE5FX
author_rank: Super Contributor
timestamp: February 27, 2018, 08:31:12 pm
content: Quote from: Fraser on February 27, 2018, 07:32:26 pmMuch appreciated. Here's a tidied-up .PDF version:Faxitron_MX20_43805_65201D_65202C_schematics.pdf(6.6 MB)These drawings apply to rev C of the 43805-65202 controller, while my PCB has revision F of the same part #. So they should be a good match. U7 is the mystery MAX202 with no Vcc connection, for instance.My 9-pin connector goes to the "Medoptics interface" at J5, which is definitely some sort of proprietary interface. One difference between revs C and F may be pin 3 of this connector. It's grounded on your rev-C schematic, while it seems to be connected to something else on the rev-F PCB. That may have been done to add proprietary control support to film-only machines.

author: danielbriggs
author_rank: Regular Contributor
timestamp: March 15, 2018, 11:21:47 pm
content: This is an interesting thread, and much along the lines of what I'm slowly heading towards with my machine.Great work kilohercas!Do you have any more details on the CBCT MATLAB route? I tried several algorithms myself, but am curious to what you used in the end as your results look really sharp.[I found while most algorithms worked, some were ultra efficient, and some took a huge amount of computational effort for mixed results].Even better... care to share you MATLAB .m files // or post an example of what you did?@KE5FX + Mike...Attached are my findings from when I was having a sniff around the RS232. It's not an exhaustive list, but contains pretty much all you'd need to run the cabinet from RS232.[Excuse the notes too, it's just what I noticed the bus doing and scribbled down the findings].

author: Manawyrm
author_rank: Contributor
timestamp: January 21, 2022, 08:33:37 pm
content: @KE5FX:Almost 4 years later, I now own one of these beautiful machines myself.I'm at the same point as you, with the same Rev. F PCB and also missing the +5V supply on the MAX202.Have you done any further work on your machine? How did it turn out?@Fraser:You seemed to have a different/newer firmware. Would you happen to have a backup copy of the EEPROM?It might be a good idea to start a little collection.My machine also has the "v3.1 MOD" ROM.Thanks,Tobi

author: KE5FX
author_rank: Super Contributor
timestamp: January 21, 2022, 08:59:10 pm
content: I haven't had time to do any more tinkering with it, unfortunately. It works well enough with the keypad, although I'd still prefer to have full remote control if it could be achieved without a lot of modification work.One thing I'm still hoping to learn is the nature of the "seasoning" requirement, in which the manual says to perform a 5-minute warmup run at 20 kV before doing anything else. Exactly how often this should be done, and exactly why it would be necessary at such low voltages, has never been explained. That's the sort of thing I'd automate if I could, but would much prefer to skip altogether.

author: Manawyrm
author_rank: Contributor
timestamp: January 21, 2022, 09:07:14 pm
content: Thanks for the reply!Have you figured out how to remove/access the sensor yet?It looks like the chassis is slightly different than described in my (slightly too new) 2009 service manual.

author: Fraser
author_rank: Super Contributor
timestamp: January 21, 2022, 09:30:06 pm
content: I sold all of my MX-20 machines so regret I cannot help with firmware images.Fraser

author: Manawyrm
author_rank: Contributor
timestamp: January 21, 2022, 10:16:15 pm
content: ... I'd love to talk more about my reverse engineering effort, should I do it here in this thread or open a new one?Anyway:I've taken a closer look at the "3.1 MOD" firmware.It's pretty straight-forward to read, but there are no references to the serial I/O ports anywhere in the code.That pretty much means that the 3.1 MOD firmware does not have any serial capabilities at all.

author: KE5FX
author_rank: Super Contributor
timestamp: January 21, 2022, 10:26:00 pm
content: Quote from: Manawyrm on January 21, 2022, 10:16:15 pmHere's good!Quote from: Manawyrm on January 21, 2022, 09:07:14 pmI had to build my owndigitizer, since my MX-20 didn't come with its original PC. I haven't made any modifications to the upper part of the machine, though, except for connecting the 'X-RAY ON' LED to the FPGA board.

author: Manawyrm
author_rank: Contributor
timestamp: January 21, 2022, 10:27:19 pm
content: QuoteHeh, yeah, I'll have to do the same thing. I had to download the pictures manually (seems to be a HTTPS->HTTP thing).Very nice board!I haven't checked yet whether my machine uses the RadEye 1 or 2 sensor. It seems to be the DC44 option model.Will open it soon.My current plan was to use one of the modern STM32H7 processors, save an image to SDRAM and then either use SPI or something else to get the picture onto my computer.

author: Manawyrm
author_rank: Contributor
timestamp: January 22, 2022, 01:20:59 am
content: @KE5FX:You wouldn't happen to have one or two raw 14-bit images, that I could use for developing my user interface while I'm waiting for my acquisition hardware?Just any format (binary, csv, etc.) would be totally fine, I can make that work

author: KE5FX
author_rank: Super Contributor
timestamp: January 22, 2022, 01:45:33 am
content: Quote from: Manawyrm on January 22, 2022, 01:20:59 amNo, my application reads the data into memory and saves it in .png format, so there is never a raw image file anywhere. It's a giant hack,feel free to snag anything you want out of it. (Probably need to enable non-https transfers for that link as well.)

author: LaserSteve
author_rank: Super Contributor
timestamp: January 23, 2022, 03:59:59 am
content: Seasoning in rotating anode tubes is done to 1. Getter the vacuum to prevent flash over. 2. Uniformly heat the whole rotating anode to prevent mechanical stress. 3. Clean the surface of the anode. 4 Bring the cooling oil to uniform temperature. 5.. Clean the bus bar tracks and brushes on the rotating gantry to ensure clean power delivery.Failing to season the tube prior to imagingWas a instant dismissal offense.Seasoning adds greatly to tube lifetime.In larger systems an anode heat capacity calculator is running in the background, to protect the tube.There was only one accepted excuse. If you were in the fieldworking on a system and an accident victim came in,If the ER physician and the radiology technician so ordered, you could skip calibration and seasoning to try to save a life.I spent a year training to be a medical CT repair instructor. The FDA shut down my employer's plant for a year, so I moved on.Steve

author: KE5FX
author_rank: Super Contributor
timestamp: January 23, 2022, 06:25:16 am
content: Quote from: LaserSteve on January 23, 2022, 03:59:59 amSure, for a high voltage, high power rotating-anode tube. But this machine has a fixed-anode 35 kV tube, with dissipation in the 10-watt neighborhood.I don't get what seasoning does, other than to accelerate tube wear. Do tubes this wimpy ever suffer from flashover?

author: LaserSteve
author_rank: Super Contributor
timestamp: January 24, 2022, 07:27:11 am
content: Yes, most x-ray tubes do suffer from random outgassing.It does not take much gas to transition from e-beam to arc.Tungsten or other refractory metal anodes are sintered from powder in a press under extreme pressure and temperature. For that reason they tend to store tiny pockets of gas. Using the heated cathode as an active getter strikes me as asking for trouble. But that is the designer's problem.Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: January 24, 2022, 05:24:51 pm
content: https://xray.oxinst.com/learning/view/article/x-ray-tube-conditioning-procedureThat settles it.Steve

author: KE5FX
author_rank: Super Contributor
timestamp: January 24, 2022, 10:25:54 pm
content: That article might "settle it" for some unspecified classes of tubes, but as usual, it fails to acknowledge the massive difference in construction and operating conditions between a 35 kV microfocus tube and a high-power rotary anode tube operating at hundreds of kV. It's like comparing a 4CX100000 to a 6AQ5. There is, again as usual, nothing type-specific to go by in this article, which is my whole beef.The procedure in the article also bears little to no resemblance to the procedure in the docs I got with the MX20. You can't adjust the tube current on the MX20, for example, only the voltage... and the operating note says to do it every day, not every 3 months.While I might prefer the 3-month advice given here because it's less trouble than doing it every day, I still don't have any reason to think it applies. Maybe it'smoreimportant to season a low-power microfocus tube frequently. Dunno.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 25, 2022, 12:23:53 am
content: The page above referenced two of their micro tube numbers. Perhaps ask either Oxford or X-Ray-Worx via email?My Googl-Fu is decent, I could find almost no detail on seasoning or conditioning microfocus tubes.After reading up on them, I'm intrigued. We have one in a mouse/rat scanner downstairs at work. One of the few instruments in my building I've never toyed with. I'll see if I can get my hands on the manual.Steve

author: Fraser
author_rank: Super Contributor
timestamp: January 25, 2022, 12:50:32 pm
content: The Faxitron Microfocus tube is made by TruFocus and their datasheet for the tube includes a warranty comment about treating the tube correctly in accordance with their use guides. It may be worth asking the people who actually manufacture this specific tube ?If you are lucky, they will provide the tube integration guide that should include operational care procedures.The tube is a TruFocus 8050 side window model.http://www.trufocus.com/xray_datasheets/microfocus/8000-SWS-Side%20Window/8050%20SWS/MFX-8050-SWS-V01.pdfTruFocus support POC: info@trufocus.comMy understanding of the need for seasoning was that if gas purity within the tube. A flashover can be catastrophic for the machine and these cost £60K in the UK so I can understand why the users are told to regularly season the tube. As a basic rule, the MX-20 was to be warmed up each day and seasoned on a specified kV for 300 Seconds. This got everything warmed up nicely ready fir the working day. It would also reveal any serviceability issues in the machine as some of these were mission critical in operating theatre for removed tissue X-Ray inspection. Of note, the kV setting fir the conditioning run varied over different user manual generations. It used to be 22kV, then 20kV and I have seen 18kV hand written over the manuals 20kV in one manual.My take on the conditioning cycle was that it gave the machine time to warm up a bit and settle down fir my imaging run. 300 Seconds was not very long to wait and the digital camera plate takes up to 30 minutes to completely warm up and settle down, if doing a calibration, so in the big scheme of things, the conditioning cycles not an issue fir me. If I had not used the machine for a few weeks I would go as far as running conditioning cycles of 300 Seconds duration at 10kV, then 15kV, then 20kV and finally 30kV. After that treatment I could be sure that the tube was nice and warm ready for it’s work. The wear on the tube was minimal but the benefit was potentially significant so I chose to treat my MX-20 machines with great care to prolong the tube life. A failed tube was normally a ‘end of life’ event for a MX-20 as the TruFocus tube was horrendously expensive. IIRC it was £5K. Why take a chance of harming the tube by not following the Faxitron tube care guidance ?Fraser

author: BUAROD
author_rank: Contributor
timestamp: January 28, 2022, 09:36:59 am
content: @kilohercas:Regarding the Hamamatsu sensor C9732DK I found this statement in your post:It can work with 100kV. In my work, i get visit from Hamamatsu, he says that problem with energy and power is that CsI will get yellow in time, but that's not a problem, since we still have so much data to work with, and we could use higher exposure times to get higher pixel values, so detector will be good for a long time.I think about replacing the TFX-8035 tube in my MX-20 e.g with a PXS10 system, which allows up to 130kV anode voltage.Beside necessary additional shielding I am concerned what will happen to the C9732DK? What do you think?Do you have more information than already written from Hamamatsu?Remark: the MX-20 is not intended to be used in continuous operation but may be once a month ...Many thanks in advance!

author: LaserSteve
author_rank: Super Contributor
timestamp: January 28, 2022, 03:34:57 pm
content: As you move to a higher power tube, you might find you need to add filters for spectral correction on the tube output if scanning organics and polymers. Higher acceleration causes spectral broadening at the source. So if it's an organic or polymer target, you can generate far more x-ray photons in a region that is not absorbed, and this could add noise to your detector that obscures weak signals. This results in a nonlinear gamma curve in organics/polymers.With a hotter tube, you will also get much more scatter off the shielding into the detector.JUST FYI:In living things, of course the goal was to tailor the spectrum to specific adsorption to reduce irradiation in the patient, achieve high contrast based on atoms present in the tissue, and reduce patient exposure to useless low energy photons. Another major consideration was designing the filter to extend scintillator lifetime. Something to think about if your imaging "soft" materials.FyI:Probably not an issue with a micro-focus tube, but with larger anodes the filters were shaped to correct for the beam pattern at the detectors. Ie get rid of the Hotspot in the center and wasted energy outside the detector area that resulted in scatter that reduced contrast.Filters in my case were stacks of nylon blocks, then thin copper, aluminum, and beryllium sheetsSteve

author: BUAROD
author_rank: Contributor
timestamp: January 29, 2022, 01:08:36 pm
content: Thank you Steve for the quick reply!My area of ​​application is more the analysis of defective parts or assemblies, where I would like to see, for example,the solder balls under a BGA or the bonding wires in an IC. The 35kV are obviously not nearly enough.This issue has been raised several times here on the forums, but I haven't found a way to upgrade the MX-20 for this application.Does anyone have an idea or has this already implemented?

author: danielbriggs
author_rank: Regular Contributor
timestamp: January 29, 2022, 01:42:08 pm
content: Quote from: BUAROD on January 29, 2022, 01:08:36 pmI asked this question to MikesElectricStuff last night on the EEVBlog Live stream, and he quite correctly pointed out the Hamamatsu sensor isn't rated past 35kV, so pushing the MX-20 past 35kV would be expensive and quite involved.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 29, 2022, 07:24:33 pm
content: Golden Engineering makes some point source systems that might be useful for close in PCB inspection.Steve

author: KE5FX
author_rank: Super Contributor
timestamp: January 29, 2022, 09:18:14 pm
content: Quote from: BUAROD on January 29, 2022, 01:08:36 pmWhether 35 kV is enough depends on several things, most prominently the atomic number of the material you're shooting through and how much of it there is. 35 kV is enough to obtain photos like the ones in theother thread, many of which are on par with commercial X-ray PCB inspection systems.What the commercial inspection systems buy you is the ability to see through more layers of copper. 8 layers of 1-oz copper is about as far as I can push my own MX-20. That's sufficient for the vast majority of boards I work with.The MX-20 has incredible resolution, enough to make bond wires look like heavy cables.Of course you can only tell so much about BGA assembly quality by looking straight down at the ball-PCB interface once the beam has had to travel through the much thicker balls themselves. Stray blobs of solder will stand out nicely, for sure.You can 'overclock' the MX20 to about 37 kV, and I do think that's worthwhile, but going all the way to 50 seems inadvisable at first glance even though the tube itself is rated for it. The need for a careful radiation survey would go without question, and you'd have to back off the anode current substantially to avoid damaging the tube.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 29, 2022, 10:31:27 pm
content: Quote from: KE5FX on January 29, 2022, 09:18:14 pmISTR reading somewhere that the Hamamtsu sensor was only rated to 35kVp

author: LaserSteve
author_rank: Super Contributor
timestamp: January 30, 2022, 05:29:27 am
content: I realize that all you can control on the Faxitron is voltage and exposure time, and probably some other detector parameters. However this is still worth a read. I'm used to having time, mAS and KvP controls. In my world not having tube current control would really be depressing. Going from 35 to 37 Kv is only a 6% change.This page has a really good explanation of some basic relationships.https://howradiologyworks.com/xraycalc/Steve.

author: KE5FX
author_rank: Super Contributor
timestamp: January 30, 2022, 05:49:34 am
content: Quote from: LaserSteve on January 30, 2022, 05:29:27 amThe article points out that exposure is proportional to the fifth power of the voltage, though. ("Since x-ray exposure goes approximately as kVp5and we generally don’t think in powers of 5 a well known approximation is typically used called the 15% rule of kVp of radiography. This rule comes from the fact that 1.155~2.0. Therefore, for each increase of 15% in kVp the exposure will double. Thus, if the kVp is increased by 15% then the mA must be decreased by a factor of 2 in order to maintain constant exposure on the image receptor. ")I'll confess I don't understand where this relation could possibly come from. kVp is the spectral location of the bremsstrahlung peak, and mA is its height, isn't it? What's the physics behind the fifth-power dependency of exposure on anode voltage?

author: BUAROD
author_rank: Contributor
timestamp: January 30, 2022, 08:35:28 am
content: Thanks for the contributions!I found some interesting Hamamatsu documents on the sensors:1. Overview (page 3!)https://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwj-hqyqhdn1AhXz7rsIHWQLDEs4HhAWegQIFBAB&url=https%3A%2F%2Fwww.hakuto.com.tw%2Ftw%2Fdowfile.php%3Fp%3D72&usg=AOvVaw028KB2JaRtDm3MO6tYX3E52. Technologies (pay attention to statement on page 213 top left!)http://www.studiodentisticovenuti.it/wp-content/uploads/2012/06/x-ray-detectors.pdf3. Applicationshttp://notes-application.abcelectronique.com/233/233-48641.pdf

author: LaserSteve
author_rank: Super Contributor
timestamp: January 30, 2022, 07:56:40 pm
content: I need to pull a paper out of the library at work on Monday to get a good explanation of that 5th power rule.. It's the whole chain of transfer functions, both source and detector. It's more film oriented, but it does apply to a detector structure that does not apply signal processing to the image.Monday...Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: February 02, 2022, 08:11:45 pm
content: From:G.S. Al-Balool, D.L. Newman,The relationships between kV, mAs and thickness in film-based radiography: 25% and 15% rules. OK?,Radiography,Volume 4, Issue 2,1998,Pages 129-134,ISSN 1078-8174,https://doi.org/10.1016/S1078-8174(98)90009-8.(https://www.sciencedirect.com/science/article/pii/S1078817498900098)Abstract:Purpose: To investigate the validity of the 25% and 15% rules in manual exposure selection. Methods: The mAs required to produce a constant film density of 1.5 was determined over the X-ray tube potential range 50–150 kV for different thicknesses of water, under grid and no grid conditions. Results: The mAs change is an exponential function with depth and is dependent upon the attenuation coefficient. The 25% rule assumes a constant attenuation coefficient with a half value layer (HVL) equal to 3 cm. The results indicate that for non-grid work at low X-ray tube potentials and for grid work at higher tube potentials the 25% rule is applicable. The 15% rule implies an inverse power relationship between mAs and tube potential, the power term being 5. The results indicate that for both grid and no grid conditions the 15% rule is obeyed only over the tube potential range 50–100 kV and for thicknesses up to 15 cm. Discussion: The 25% and 15% rules have provided useful practical guidelines for exposure factor selection. It is shown that they are applicable to some but not all radiographic situations.Keywords: exposure factors; selection; 25% rule; 15% ruleSimplified Conclusion of the paper: 15% rule holds for tissue of less then 13 cm thickness and Voltages less then 100 kV.For other more drastic conditions the 20$% rule holds.I quote:" In fixed kV techniques, the 25% rule is widelyapplied [1, 2]. This states that for every I cmchange in patient thickness a 25% mAs change isrequired. This rule derives from the exponentialattenuation relationship in that the required mAschange is proportional to e ^ ±Hx where His theattenuation coefficient and x the thickness, the signdepending on whether an increase or decrease inmAs is required, i.e. whether there is an increase ordecrease in patient thickness. Therefore, as thethickness changes the mAs needs to be changedexponentially to maintain constant film blackening.For the 25% per cm rule to apply over the wholerange of diagnostic tube potentials,/a is assumed toremain constant and equal to 0.23I c m - ~ i.e. a halfvalue layer (HVL) for soft tissue of 3 cm. This, ofcourse is a simplification since 1~and hence HVL areenergy dependent. However, the mAs stationson many X-ray units today follow this rule in thateach consecutive mAs step represents a change of25%. Thus, in fixed kV techniques, thicknesschanges can be compensated by appropriate stepchanges in mAs."For the 15% rule:I quote"In variable kV techniques the situation is not asstraightforward because there are a number of kVdependent changes that take place when the tubepotential is varied. These include changes in tubeoutput, X-ray attenuation (absorption and scatter)and film screen speed. At a given patient thickness,adjustment of the tube potential requires a compen-satory adjustment in mAs so that the resultantexposure produces the same level of film blacken-ing. The so-called 15% rule [3-6] has been used asa guide to the change in mAs that is required. Thisrule states that to achieve the same film blackening,a 15% change in kV requires a compensatorychange in mAs of a factor of 2. If an inverse powerrelationship exists between mAs and tube poten-tial, this rule assumes that the power term is 5,since 1.15s=2, i.e. mAscz kV -5. This rule resultsfrom the relationships between mAs and tubepotential in determining X-ray output, attenuationand film screen response. With the introduction ofhigh frequency generators and energy-dependentintensifying screens it is possible that these rela-tionships have changed and hence the rules maynow not be applicable or at least need to beamended"REFERENCES for above PAPER:A KellyBlack or white?—hit or miss?The Radiographer, 35 (1988), pp. 19-26View Record in ScopusGoogle Scholar2.Why exposure tables with a point system?, Siemens Radiographic World News (1962)SiemensGoogle Scholar3.RR Carlton, A AdlerPrinciples of Radiographic ImagingDelmar Publishers Inc, Albany (1992), pp. 480-481Google Scholar4.JC Malott, J FodorThe Art and Science of Medical Radiography(7th edn.), Mosby Year Book Inc, St Louis (1993), pp. 130-131Google Scholar5.QB CarrollRadiographic Exposure, Processing and Quality Control(5th edn.), Charles Thomas, Springfield (1993), pp. 102-106CrossRefGoogle Scholar6.JE WallaceRadiographic ExposurePrinciples and Practice, Davis Co, Philadelphia (1995), pp. 92-96View Record in ScopusGoogle Scholar7.DN Chesney, MO ChesneyRadiographic Photography(3rd edn.), Blackwell Scientific Publications, Oxford (1971), p. 293View Record in ScopusGoogle Scholar

author: CwazyWabbit
author_rank: Newbie
timestamp: February 10, 2022, 02:15:51 pm
content: Found this info on the serial protocol being used, not sure if it adds any more to what you already know though.

author: Andrew Seltzman
author_rank: Newbie
timestamp: February 23, 2022, 02:33:22 pm
content: @danielbriggsI wrote a MATLAB package for cone beam CT on the DX-50, it should run the MX-20 since it uses the same protocol.http://www.rtftechnologies.org/physics/faxitron-DX50-CT-scan.html

author: danielbriggs
author_rank: Regular Contributor
timestamp: February 24, 2022, 10:00:42 pm
content: Thank you Andrew! Really impressive work.What an excellent resource on your site. I'll work my way through the videos, and adapt any code where appropriate for my MX-20.

author: MindBender
author_rank: Regular Contributor
timestamp: May 20, 2022, 04:23:52 pm
content: Quote from: Andrew Seltzman on February 23, 2022, 02:33:22 pmWould you consider sharing the source?

author: CwazyWabbit
author_rank: Newbie
timestamp: May 27, 2022, 06:16:22 am
content: Looks like they are on his website, follow the link in his message.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 11, 2022, 10:33:56 am
content: I found a Faxitron unit on eBay with a DC44 for a reasonable enough price that I immediately bought it.Has there been any progress in reverse engineering the interface for it, or is it possible to reasonably replace the imaging sensor?

author: KE5FX
author_rank: Super Contributor
timestamp: November 11, 2022, 07:48:09 pm
content: Quote from: KaneTW on November 11, 2022, 10:33:56 amThisis still a good source of info to start with. I archived it under docs/Haidekker in the zipfile in reply #52 above, if you haven't seen that yet.There is probably no point in replacing the Bioptics sensor unless you can find a Hamamatsu panel.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 15, 2022, 10:44:40 am
content: Quote from: KaneTW on November 11, 2022, 10:33:56 amSmall update, the seller had a DC12 unit available and is sending that instead.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 22, 2022, 05:51:57 pm
content: Unit arrived. Seems in good condition, except:* Tube current output shows something weird. -0.20V in VDC, 0.06V in VAC, 0.21V in VDC+AC. Voltage is on point. There's an image produced and I have no idea what's causing the weird current readout.* Rear USB-A to USB-A adapter didn't work, I had to remove it and connect the cable directly for my PC to detect the sensor.Apart from the weird tube current issue everything looks ok.

author: Fraser
author_rank: Super Contributor
timestamp: November 22, 2022, 07:40:30 pm
content: SR Software and Technical manual link sent today. Hopefully that will assist you in testing your unit.Fraser

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 23, 2022, 08:55:24 pm
content: I queried Gamma High Voltage and the current monitoring is a 1kOhm resistor + capacitor + 2 Diodes placed across GND and HV return. So a negative voltage is expected. This is also confirmed by the schematic having an inverting amplifier (-10x) on mA feedback.I believe the oscillation is actually occuring in that case and not just a readout bug. Once I have the chance I'll probe the current setpoint and see if it's oscillating as well.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 24, 2022, 06:58:42 pm
content: I've probed the current monitor with my scope and the it looks like EMI to me. I've debugged further and noticed a peculiarity.There's a reed relay (Fraser, can I post the schematic?) K1 that ultimately switches the L2-Current an L3-Focus outputs. It does so via switching the wiper output from the L2/L3 pot to an opamp.The voltage before the relay is nominal. The voltage after the relay is much higher -- I've measured:Wiper: 1.31V, node after relay (R5/R3) 3.3Vthen 1.47V -> 5.26V, then 1.56V -> 6.08VThe inverting output is at most 2.3V, so the opamp goes to its max possible output of 10.5V pretty quick, which corresponds to about 9.2V on the BJT emitter that is upconverted to the tube control voltage.I need to take out the gun board and probe some more, but it's a huge pain to reach the bottom srcrews...

author: Fraser
author_rank: Super Contributor
timestamp: November 24, 2022, 07:05:59 pm
content: No objection to showing the schematics.I will look in the service manual to see if there is anything in there to assist you.Fraser

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 24, 2022, 08:15:17 pm
content: Here's the set of links:Gun board:https://i.kane.cx/dFTeBuhttps://i.kane.cx/8JmAtuhttps://i.kane.cx/xvgpbQController board:https://i.kane.cx/H7T6TIhttps://i.kane.cx/GmY9hVhttps://i.kane.cx/VGPG0vhttps://i.kane.cx/TGXgZRGun board annotated with measurements:Thermal cam shot:The component getting hot is the reed relay K1. The temperature did not noticeably change whether it was on or off.Some scope shots of the mA current output:10kV:https://i.kane.cx/Mh6Z1ihttps://i.kane.cx/qQl6TF20kV:https://i.kane.cx/FQfNOjhttps://i.kane.cx/3cXARo35kV:https://i.kane.cx/s8l59Jhttps://i.kane.cx/gcR71oThe high frequency content is always present and I'm pretty sure it's just EMI/bad probing (the current output port only fits a multimeter lead). The ~25kHz content however is increasing with increased kV, so something's weird there. Note that the average remains roughly constant at -250mV.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 29, 2022, 01:08:21 am
content: After some debugging I noticed that L2Q was set to a way higher value than the manual specified, around -280V. It does claim that you need to follow the tube test sheet but I adjusted it to -200 or so and got closer to the 0.3mA of current that it should have. Still can't go above it (so really bad SNR at lower voltages) but that's good enough for me since I image at max voltage.Some images of a 10-layer board attached.

author: rickells
author_rank: Regular Contributor
timestamp: April 24, 2024, 04:51:11 pm
content: New thread on newer BiOptics Bio Vision BioVision Faxitron units ca. ~ 2009 - 2015See:https://www.eevblog.com/forum/reviews/faxitron-biovisionbioptics-win7-(pci-resource-issue)/new/#new

author: danielbriggs
author_rank: Regular Contributor
timestamp: June 17, 2024, 09:01:24 pm
content: Quote from: mikeselectricstuff on February 13, 2018, 10:42:47 amSorry to grave dig an ancient comment / thread, but just figured something out with this that might help future people.I had my Faxitron MX-20 working well for years on Win XP, bur recently replaced with a "new" Win 7 32-bit machine to run other various old stuff here (The Faxitron included).After a full clean install of the Faxitron software I was running up against issues with it not allowing any exposure of 2 secs + failing to calibrate (needs a 3.5sec exposure).I figured out this maximum exposure limit comes from a registry key.You can change it to any value you wantThe default the DCAM API installs is 2, so I changed it to 20, (as the Faxitron software works up to 19 sec I recall).HKEY_LOCAL_MACHINE\SOFTWARE\Hamamatsu\DCAM\Modules\husb2\deviceAnd edit whichever sensor / camera you have.In my case I changed the C9732DK string fromFPS:EXP(1,2)toFPS:EXP(1,20)and everything magically started working.I don't know what the upper limit to this value is.I used:Windows 7 32-bitDCAM API 13.10.4418Faxitron SR 1.6Sensor: C9732DK (12cm sensor)(I believe DCAM API 13 to 19 will work for Win 7, but I'm unsure where it breaks down with Faxitron 1.6. V13 definitely works great on Win 7 and XP.)Maybe I installed things out of order and the Faxitron software changes this registry key? Who knows, but hopefully this post will help any future Faxitron MX-20 users.All the best,Dan

author: KE5FX
author_rank: Super Contributor
timestamp: June 18, 2024, 12:28:03 am
content: Interesting. How are people supposed to season the tube, if the default exposure is limited to 2 seconds? Is there a separate function in the software for that?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 18, 2024, 04:17:50 am
content: Quote from: KE5FX on June 18, 2024, 12:28:03 amYou can use the front panel controls before running the software

author: kilohercas
author_rank: Regular Contributor
timestamp: November 29, 2024, 03:18:29 pm
content: Register update does not work for me, I set 10s, and read value back, it always is capped between 1 and 2s of exposure. I would love to have 10 or even 20s exposures, it looks it must be done in program by summing data...