hybridfree/eevblog-posts huggingface dataset:
ASL F25 Thermometer - Page 1
Forum section: electronics / general

author: Sengcid
author_rank: Regular Contributor
timestamp: December 12, 2021, 05:06:11 pm
content: If you are trying to fix or adjust for best accuracy the attached may be useful.

author: mendip_discovery
author_rank: Super Contributor
timestamp: December 12, 2021, 05:30:45 pm
content: Also suggest you upload that to TiNs little repository of handy manuals over at xdevs, see the contact page for FTP details,https://xdevs.com/contact/

author: doktor pyta
author_rank: Frequent Contributor
timestamp: December 12, 2021, 08:55:58 pm
content: Sengcid,Thank You very much for a detailed analysis!

author: Robert763
author_rank: Super Contributor
timestamp: May 21, 2024, 09:07:47 pm
content: @SengsidIntereting document. You don't happen to have the operaing manual by any chance?I've just aquired one of these and it'e always nice to have the manual.Robert.

author: Electrole
author_rank: Contributor
timestamp: May 22, 2024, 04:21:51 pm
content: I just made a scan of the Model F25 Operator's Handbook (an original copy from ASL.)The version has been compressed to get below the 8000KB limit, but it's still readable.Enjoy!

author: Robert763
author_rank: Super Contributor
timestamp: May 22, 2024, 06:40:26 pm
content: Hi Electrole,Thanks for that. The F25 looks like a great little meter. Not quite as accurate as my Cropico 3000 (25mK Vis 10mK) but smaller and easier to use. Cost £28 including 2 probes and shipping (ebay) so had to have it....Robert.

author: Overspeed
author_rank: Frequent Contributor
timestamp: May 23, 2024, 04:30:51 am
content: HelloThanks for the PDF as ASL is verycompany regarding documentation and support even if they produce nice thermometerRegardsOS
yokogawa gm10 - Page 1
Forum section: electronics / general

author: Louis_C
author_rank: Contributor
timestamp: June 21, 2024, 12:37:40 pm
content: Has anyone here had any experience calibrating a Yokogawa GM10 with the GX90XA-10-U2 modules? I'm just looking for any inside info to make the calibration procedure easier. Our lab has never performed a cal on this unit and I could use some assistance on this. Thanks!

author: Poroit
author_rank: Frequent Contributor
timestamp: June 21, 2024, 01:13:15 pm
content: What parameter does your customer measure with this?Only calibrate it on the ranges that your customer is interested in.

author: Louis_C
author_rank: Contributor
timestamp: June 21, 2024, 02:06:09 pm
content: Thanks for the reply. I'm waiting to find out what the customers usage is. They produce HUGE commercial battery backups so, I would think they would monitor voltage, current, TC. We were planning on doing five tests per module of voltage, current, resistance, TC and RTD. If I can do less, the better. The browser interface and associated PDF's are very complex and there is a lot of information with the unit.

author: mendip_discovery
author_rank: Super Contributor
timestamp: June 22, 2024, 10:30:19 am
content: I have seen certs for multi-channel loggers where only one channel gets a full run through and the others just get a small number of checks to see they are not broken.
Wanted CODAM BASIC/PLUS software version 2.0.0.0 - LEM memobox 300 - Page 1
Forum section: electronics / general

author: EDER
author_rank: Contributor
timestamp: May 14, 2024, 11:19:41 pm
content: Hello, I am looking for the CODAM BASIC/PLUS version 2.0.0.0 software to connect and configure my MEMOBOX 300 recorder.I downloaded the software version 4.1.2.6 from the website, however, the device manages to connect but I get an error message when trying to establish a task, apparently the version is new for a discontinued/old device.If anyone can share the software with me I would greatly appreciate it. Or we can also reach an agreement.Good day.Kind regards
Probably SCAM Just a head-up:734a with 4x 732b - Page 1
Forum section: electronics / general

author: tatel
author_rank: Frequent Contributor
timestamp: May 18, 2024, 03:42:59 pm
content: EDIT: reported in buy/sell/wanted, but I think this is the section where most people would be interested. Not related in any way, and definitely out of my league, but I bet there's people here that will know if it's good for him or nothttps://www.ebay.com/itm/186447948693PS: it looks as if a legit seller account has been broken into. Heard about other similar cases but it's the first time I see it live.

author: Harfner
author_rank: Contributor
timestamp: May 19, 2024, 11:43:30 am
content: Yes, looks like a textbook example. In addition to everything which would produce large amounts of drool here (several Fluke calibrators!) there is gold, diamonds, furs, special guitars, rare collectibles ... Everything under the sun which can be valuable in used condition.

author: factory
author_rank: Super Contributor
timestamp: May 19, 2024, 12:34:13 pm
content: Definitely a hacked account, the seller is UK based and looking under sold items, normally sells low value plant & tree seeds.David
calibrator reboots - Page 1
Forum section: electronics / general

author: Louis_C
author_rank: Contributor
timestamp: May 17, 2024, 08:01:51 pm
content: my company has a Fluke 5500A connected to a Windows 10 machine with a USB GPIB-HS adapter. We are running Fluke Met/Track 8.3.2. When I try to run ANY procedure, the calibrator will REBOOT and the runtime will error out. In NIMax, I can SEE and QUERY the calibrator with no problem. When I run NI I/O trace and watch the procedure load, all the I/O trace shows is NOADDR.

author: Arhigos
author_rank: Regular Contributor
timestamp: May 18, 2024, 07:07:26 am
content: Maybe try a different version of met/cal first?There is a free 30-day trial version of met/cal 11.0 available. It will not run PROC procedures from 8.0, but PXE will be fine.
A peek inside the Voltcraft VC891 Handheld DMM - Page 1
Forum section: electronics / general

author: QOTF-Alexi
author_rank: Newbie
timestamp: May 09, 2024, 08:12:28 pm
content: I recently bought this meter on Conrad.nl for €270 (normal price €299) and decided to follow Dave's advice and take it apart. I do not know much about multimeter guts but it doesn't look very impressive. I did not remove the metal shield because I didn't want to risk accidents, so we can only guess at the multimeter IC, although I suspect it might be identical to that of the Uni-T UT171, since Uni-T is the ODM of Voltcraft DMMs and the features of the UT171 seem similar. The knob is permanently attached to the front case.Images: front & back of PCB, contents of box.

author: QOTF-Alexi
author_rank: Newbie
timestamp: May 09, 2024, 08:14:38 pm
content: Some close up pics of the CPU, bluetooth module and stuff around the input jacks.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 09, 2024, 09:16:49 pm
content: I'm not a fan of placing the vias in the center of the function switch contacts. It looks like the typical 5mm PTCs are used without any additional limiting. For $300 USD, I would expect a lot more.

author: QOTF-Alexi
author_rank: Newbie
timestamp: May 10, 2024, 06:49:01 am
content: I've also run a few tests now and the resistance & capacitance meter, diode test and continuity test are very, VERY slow. For example it takes about 0.5-1 second for the beeper to sound on continuity and 2-15 seconds on resistance/capacitance, depending on how large or small your resistor/capacitor is. All the other functions are fast at least.I do still have a no questions asked return window and I am low-key considering it, but then I'd have to fall back to my 1999 count Metex M3800, of which the calibration has drifted so far it's barely usable.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 10, 2024, 03:04:58 pm
content: Voltcraft is the low end "in house" Conrad brand and the quality is not the best, to say it carefully.I am surprised they can sell it for so much money.For this amount of money, you can get something real good, used and new.

author: J-R
author_rank: Super Contributor
timestamp: May 12, 2024, 12:40:43 am
content: I just had to have a lit selector switch too:https://www.eevblog.com/forum/testgear/121gw-lit-selector-switch/

author: Gyro
author_rank: Super Contributor
timestamp: May 12, 2024, 09:57:49 am
content: Quote from: J-R on May 12, 2024, 12:40:43 amHow do they keep the LED stationary in center of the knob (presumably there is a rotating light guide)? I can't see any way of restraining it apart from the stiffness LED leads themselves going down the center hole.

author: QOTF-Alexi
author_rank: Newbie
timestamp: May 12, 2024, 10:06:33 am
content: Going by the rest of the meter's innards, I would not be surprised if the LED is actually mounted at the end that lights up, with the wires tangling and untangling when the knob is turned.

author: Gyro
author_rank: Super Contributor
timestamp: May 12, 2024, 10:34:40 am
content: Yuk, I hope not.
Keysigh 3458a ERRSTR 202, “HARDWARE FAILURE – SLAVE TEST: DC BOARD” - Page 1
Forum section: electronics / general

author: skjafar
author_rank: Contributor
timestamp: May 05, 2024, 05:41:44 am
content: Hello all.It's a wonderful machine when it runs properly!I have the following error when the device finishes the self-test:ERRSTR 202, “HARDWARE FAILURE – SLAVE TEST: DC BOARD”No other errors reported.No output is given at any measurement, the screen stays blank without any number. Even TRIG didn't trigger.We sent the device for service at Keysight and asked for "only" $7.5k to replace the DC Board and A/D board plus a calibration. I didn't foresee such a bill. So I didn't do the repair. It's such a valuable device to sit as a paper-weight though. Please help me get it running again.Here are the faults reported by Keysight:Time out unable to read A/D. Cal value Out of Range "95"Can anyone who knows this device explain what this means?I have started probing around in the device last week, and so far I have found that U2 (buffer that controls input relays) is not working, this failure could explain the DC BOARD error. I have suspicion that this is not the only problem!Please note that this is a device I bought brand new and it was never tampered with before this incident.
measuring 100mA current source with a better than Keithley 2000 - Page 1
Forum section: electronics / general

author: Overspeed
author_rank: Frequent Contributor
timestamp: May 02, 2024, 03:38:33 pm
content: HelloI need the measure a pulsed current with a frequency of 2 to 5 Hertz and a max value of 100 mA ( stable frequency no sweep )What I need to set as circuit ?I suppose the circuit will a be a precision resistor with a low noise Op Amp to built a 4 wire measurement setup to built a 4 wire measurementI suppose I need to control the shunt resistor temperatureI have built several basic shunt measurement circuit but what is the best setup regarding the fact to reach a better resolution than 100 nA ( the published resolution of a Keithley 2000 ) I have a Hioki DM7275 7.5 digit and Also a Keithley 182RegardsOS

author: The Soulman
author_rank: Super Contributor
timestamp: May 02, 2024, 05:19:52 pm
content: Your best bet is the Hioki on the 120mV range in 7,5 digit mode (is the sample rate high enough?) with an external 1 Ohm shunt.100mA reads 100mv and the least significant digit is 10nA, speed and accuracy may not be great.Power loss in the shunt 0,1V*0,1A=0,01W or 10mW, easily manageable.You could add a op amp to the above and amplify the shunt signal 10x or 100x for 1nA or 0,1nA resolution but you would need some range switching in that case.What is the duration of your current pulse and how accurately do you need to measure it?And why do you need that much resolution?

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 02, 2024, 11:44:43 pm
content: The question is not stated correctly. With the Hioki and a reasonable quality 1 Ohm shunt is not difficult to measure 100mA current better than the Keithley 2000 does it. The reason is very simple, the K2000 is very noisy compared to the Hioki. on 100mA DC range the last digit of the Keithley with be 100nA per unit. However on the fast (=NPLC1) speed (which will be required to get the bandwidth of 10Hz+) the p-p noise of the K2000 will be 30uA or about 300 times 100nA. The Hioki has p-p noise on NPLC1 about 0.4uV on 100mV range and about 1.5uV on 1V range. Even with 0.1 Ohm shunt as in K2000 it will translate into 4uA p-p, with 1 Ohm shunt it should be close to 0.4uA and can be pushed to as little as 150nA p-p with 10 Ohm shunt (if you can afford 1V voltage drop). Which is about 200 times better than what the Keithley 2000 can do.CheersAlexP.S. - I have both Keithley 2015 (which is the same as K2000 in DCI mode) and Hioki DM7275 in my home lab, as well as quality 1 Ohm and 10 Ohm shunts with ppm level of stability, so the numbers above I took from my own measurements. In the attachment the Hioki measures 1V output at NPLC1 ("Fast") from a very low noise source - Fluke 731B, with p-p noise below 0.3ppm (so the noise of the source is well below the noise of the meter).
Wenzel 500-04208C pinout? - Page 1
Forum section: electronics / general

author: EE4all
author_rank: Regular Contributor
timestamp: May 13, 2024, 08:53:45 pm
content: Can someone help out here? I didn't find any information on this one, or a similar can.

author: EE4all
author_rank: Regular Contributor
timestamp: May 13, 2024, 09:51:22 pm
content: Black is ground. VCC being yellow or orange is the the real question.

author: EE4all
author_rank: Regular Contributor
timestamp: May 13, 2024, 10:27:17 pm
content: OK, orange is VCC and yellow is tuning. It's a Small Fry variety. I am not sure why I couldn't find it earlier.
Keysight 34450A Help - Page 1
Forum section: electronics / general

author: Louis_C
author_rank: Contributor
timestamp: May 02, 2024, 01:08:55 pm
content: Hello all. I'm looking for some help on a Keysight 34450A. All calibration tests pass except for 100mV AC @ 100kHz. It reads 94.837. The Low limit is 96.700 and the high is 103.3. I tried performing the internal calibration and entering the new corrected reading for this test point and the unit rejects it and fails. I flashed the firmware to the latest version available ( 01.03-01.02). I'm not sure what else to do here. Can anyone give me some advice as to what to look at next? Thanks!
A rare sale of a full ESI SR1010 set - Page 1
Forum section: electronics / general

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 01, 2024, 11:30:32 pm
content: Posting here as it is a strictly metrology related thing. I have no association with the seller.https://www.ebay.com/itm/315284985670I would buy itbut delivery and custom charges push it out of my reach (plus I already own four out of six SR1010s). It is a rare sale and I hope someone will find this information useful.CheersAlex
Anyone had succes in getting calibration history from cal-lab on used equipment? - Page 1
Forum section: electronics / general

author: aronake
author_rank: Frequent Contributor
timestamp: May 01, 2024, 03:40:01 pm
content: Anyone have had success in approaching a calibration laboratory to get historic calibration data for some device bought used?My particular case is a Fluke 732B which according to the calibration sticker was calibrated in December 2023. It was bought from a surplus electronics store so they had no clue about anything like calibration. The unit seems to be from early 2000. It would happily pay quite some money if i could get the calibration history, assuming it has not been adjusted and it would give a good drift history.I will of course make a try to approach the calibration laboratory and see if it may work. But checking here first to see if there are any experience in this area.I think the chances i can get the data is quite small. And will offer money for it. So lets see. And much equipment get adjusted when calibrated, so history less important. But for a voltage reference that has likely not been adjusted, it would be very valuable.

author: TheSteve
author_rank: Unknown
timestamp: May 01, 2024, 04:34:51 pm
content: I bought a used 732A and contacted the cal lab that had last calibrated it. They wouldn't give any official documentation but were nice enough to send me the last measured values and associated uncertainties for no charge. It is certainly worth asking.

author: mendip_discovery
author_rank: Super Contributor
timestamp: May 01, 2024, 04:43:36 pm
content: I have heard one lab saying its covered by the Data Protection Act, but if a request came to me at the lab I work at I would send the results, though I might remove the company that it was done for.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 02, 2024, 12:27:23 am
content: Quote from: TheSteve on May 01, 2024, 04:34:51 pmKeysight actually did this for me, once upon a time which was a few years back - before they forgot who pays the bills. I resold a used 34401A to member here that I had purchased on eBay that was still in KS cal. He asked if I could get a cal cert for him. I did. Perhaps it helped that I asked on my company email which was a $40B global company. Yeah, I know I shouldn’t have done that… but it worked.
Datron 4808 with an indentity crisis - Page 1
Forum section: electronics / general

author: binary01
author_rank: Contributor
timestamp: May 01, 2024, 07:50:13 am
content: Hi team.I have an odd question that I am hoping some of you might be able to shed some light on. I recently acquired a used Datron calibrator from the online gambling centre (beginning with e), which I believe is a 4808, but on closer inspection, it is showing limitations in accordance with the performance of a 4805. For instance, it can only generate ACV up to 100 kHz, and the display resolution is 6.5d / 5.5d rather than 7.5d / 6.5d. I have lifted the lid and checked the P/Ns of all boards and all boards are matching the 4808 parts rather than 4805, so Ithinkthe guts belong to 4808.Does anyone have any clues? My first guess was that one of the boards must have failed and was replaced with a 4805, but even the board that houses the EEPROM appears to be from a 4808...Thanks, Liam
Automated PCB reverse engineering idea - Page 1
Forum section: electronics / general

author: Rjc987
author_rank: Contributor
timestamp: April 25, 2024, 04:59:10 pm
content: Hey guys,One piece of test equipment I've never seen is an automated PCB reverse engineering solution - something that could take a PCB and either through imagery or direct measurement, output a general schematic of what connects to what. there's been times when I've been very busy and get in a piece of equipment that has a convoluted board which I don't have any schematics or information about and which something like that would be a huge timesaver and a massive help when reverse engineering or diagnosing.So I was wondering why and thinking about ways it could be done - the first idea I had was using simple pcb imagery and machine learning but the fact that traces are hidden underneath ic's and inner layers, plus perspective and lighting means bigger components are going to be blocking things, and glossy black or white solder masks make it almost impossible to get a clear image of traces etc. I feel like that might not work very well.So how about this- just a simple, very dense bed of nails style fixture completely filled top and bottom, Connected in some matrix array allowing a continuity signal to be applied sequentially from pin to pin and record every other pin which has continuity or a resistance value. This could then be processed into a boardview type file using images of the boards with each node selectable to display all related connections. It obviously won't work with bga's etc, and it would probably work best for low to medium density PCBs but am I missing anything here? It doesn't seem like it would be that difficult of a project to me, I imagine the hardest part would be the coding. Any thoughts? Suggestions?

author: pcprogrammer
author_rank: Super Contributor
timestamp: April 25, 2024, 05:45:52 pm
content: I see problems with the bed of nails and component height, and not just BGA's that pose a problem. QFN packages also have the pads underneath, and there are other components with the connections underneath the component, like some coils, LED's, etc.Even with pogo pins there can be components in the way for reaching in deep enough to make contact. Flying probes would be a better solution, but it would need a robot arm with good articulation and a long needle to reach in to every nook and granny, and that still leaves BGA'sAn X-ray image of the board can be of help, but with multi layer boards it still is a challenge.Further more it would need automated recognition of components, and that can be difficult too, with the same SMD marking on different components, so knowing the package is also needed, and then still.Distinguishing a SMD ferrite bead from a SMD capacitor can also be a challenge, and components with very low resistance can mislead the continuity test and make it think there is a direct connection.Distilling a proper schematic is also not that easy, even with a full node to node list.So all in al not an easy feat to accomplish.
Symmetricom XLi firmware? - Page 1
Forum section: electronics / general

author: mcguire
author_rank: Contributor
timestamp: April 04, 2024, 04:25:03 pm
content: Hi, does anyone have firmware update files for the Symmetricom XLi? I think the latest is v2.4 but am not certain.Thanks,-Dave McGuire

author: rplabs
author_rank: Contributor
timestamp: April 15, 2024, 09:20:09 am
content: I attached the firmware file version 2.4.
LT1021C-10 vs LT1236A-10 - Page 1
Forum section: electronics / general

author: Majorassburn
author_rank: Regular Contributor
timestamp: April 14, 2024, 05:10:11 pm
content: My duplicate question. Please disregard. Thanks.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: April 14, 2024, 07:24:11 pm
content: Youdid ask this question beforeCheersAlex
Profile of a surface/point instead of flatness? - Page 1
Forum section: electronics / general

author: eric37
author_rank: Newbie
timestamp: April 10, 2024, 01:19:52 am
content: So, a customer has asked for the flatness of some of their products to be checked after they were found to be quite bent. Unfortunately their drawing only calls for surface profile. It's a relatively straight edge, so I was thinking of either creating a plane from already programmed points to create flatness, or using the already called out profile for the points to work out the flatness.

author: rubidium
author_rank: Regular Contributor
timestamp: April 10, 2024, 04:28:27 pm
content: How much/little is "quite bent?" If it's on the order of 0.0001" or greater, wouldn't a good dial indicator and base, together with a granite surface plate suffice?. If the deviations are a lot smaller, you might consider checking the surfaces visually with an optical flat and (near) monochromatic light, say from a sodium-vapor lamp, and counting fringes.

author: DaJMasta
author_rank: Super Contributor
timestamp: April 14, 2024, 02:58:00 am
content: Are you looking for a way to calculate flatness, represent flatness, measure flatness, or correct it?For measuring, the above seem to be the go-to. A heightmap of points and a little visualization does wonders for demonstrating it, but depending on the kinds of features and requirements of the part, a meaningful measurement for it has to be picked from a variety of potential representations.
Si Time SiT5721 calibration - Page 1
Forum section: electronics / general

author: ve2mrx
author_rank: Regular Contributor
timestamp: February 21, 2024, 02:40:41 am
content: Hi fellow geeks,Would any of you know how to calibrate an Si Time SiT5721 frequency source?I have one, I can read/write to it but I'm not too sure how to calculate the Pull Value and Aging compensation.Any pointers?EDIT: It is connected to a uBlox LEA-M8F and I look at UBX-TIM-SMEAS messages. It is configured as an external frequency source in the GNSS, itself configured as a PPS source.Thanks,Martin

author: dizcza
author_rank: Newbie
timestamp: March 06, 2024, 06:55:00 am
content: Regarding aging compensation, I took the PID implementation fromhttps://github.com/liebman/esp32-gps-ntp. I haven't changed the constants and it works fine for both DS3231 and RV3032.I'd like to ask you how you managed to receive UBX-TIM-SMEAS messages in LEA-M8? Are they sent automatically after a fix or you send a configuration command (UBX-CFG-SMGR)?

author: ve2mrx
author_rank: Regular Contributor
timestamp: April 13, 2024, 04:27:01 pm
content: Hi dizcza,Quote from: dizcza on March 06, 2024, 06:55:00 amI enabled the UBX-TIM-SMEAS message in uBlox u-Center after configuring UBX-CFG-ESRC and UBX-CFG-SMGR. The UBX-CFG-MSG command can be used to enable UBX-TIM-SMEAS every second, and this is what I did.To calibrate the SiT5721, I mostly figured out the math using 2-point linear algebra in a spreadsheet. My SiT5721 is operating in the linear aging region now, so it works well enough so far. I can get 0.8 ppb precision easily. It is all manual so far, but I will likely try to automate it using Python at some point. I'm in no rush, so I'll check out the PID implementation you mentioned! It would be nice to have the pull value and aging compensation to auto-set!I learned that to use GPS as a frequency standard transfer mechanism, you need to use one exact day (86400 seconds) for measurements, meaning one adjustment per day with accuracy. I found that I could use a 1h measurement to set a coarse pull value, and then wait 86400 seconds to get the accurate pull value. This sets the frequency offset to zero at the time I set the accurate pull value, so I need another 86400 seconds to measure crystal aging compensation. I believe it is the 24h drift/86400s, this is where I am now!If I was a math genius, I'd use something more advanced than 2-point linear equations, but the simplicity helps grasp the principles at play. Maybe this will be easier to do once I start using Python to pull uBlox messages and set the SiTime device!Martin
Help requested for repair of Efratom FRS-C rubidium oscillator - Page 1
Forum section: electronics / general

author: ejd.pol
author_rank: Contributor
timestamp: April 08, 2024, 08:15:18 pm
content: [This was posted originally in the Repair section of the forum, and reposted here as advised by a reader.][In the mean time, I am studying the Efratom manuals, to see if I can figure out what new measurements could shed more light on this.]Hello,Recently I have acquired a faulty Efratom FRS-C 2A8A4C Rubidium oscillator. It was the internal reference of a PM6685 frequency counter.The supply of the frequency counter is toast, and maybe the main board is too. So I am in the process of seeing what can be salvaged.The first and foremost thing to try to save is the reference. The serial number of the oscillator is 20702, date code 50/94.Unfortunately, the coax output signal is not the expected 10 MHz sine wave. Instead, the output is a sine wave that hovers somewhere around 60 Hz.Fortunately though, the device still seems to be able to lock: after a few minutes warming up (it does get warm), the "unlock" led goes off.So this gives me some hope that not all is lost, and a repair is possible.(The unlock led is connected to pin 1 of the external connector: lock monitor. It is on when not in lock, and off when it is.)So, I took off the top cover, to see what was underneath. A nice construction of four boards making up the sides, interconnected by a flex board on top.The flex board seems to have a number of numbered test points, so I measured the DC values on these points, after warming up and unlock off.2: 0.65 V3: 6.38 V4: 2.55 V5: 23.22 V6: 17.09 V7: 0.00 V (I used this point as measurement reference for the other points)8: 8.86 V10: 5.92 V11: 5.75 V12: 0.00 V13: 0.00 V14: 2.51 VWhile doing these measurements, i noticed that point 11 is very sensitive: by just touching it, I can unlock the device (led on).And in that state, I can see on my scope that the output sine frequency changes, and even seems to cross 0 Hz.The highest frequency that it produces during the sweep is about 160 Hz.Perhaps the symptoms as described are known for the FRS-C type, and hopefully the repair is known as well.Of course, more measurements can be taken (DMM or scope) if useful.I have found some documentation on the FRS-C on the web, but the complexity involved is daunting. [well, not too bad, actually!]I hope someone can give me some guidance on how best to proceed.I have taken some pictures of the disassembly, so if there is any interest, I can post these as well.Many thanks in advance, Evert-Jan

author: Halcyon
author_rank: Unknown
timestamp: April 08, 2024, 11:25:30 pm
content: Duplicate thread.
Calibration certificate Fluke 5790 - Page 1
Forum section: electronics / general

author: Laurent G
author_rank: Newbie
timestamp: April 08, 2024, 07:03:04 pm
content: Good evening,I’m looking for a calibration certificate for a Fluke 5790. I need to be able to estimate an uncertainty budget and compare it to an uncertainty budget using a Fluke 792.I will miss the repeatability part, but I would already have a base to give the best information.Sincerely,
Cohu 355 DC Voltage Standard - Page 1
Forum section: electronics / general

author: Solodolo47
author_rank: Newbie
timestamp: March 04, 2024, 01:56:12 am
content: Hello, does anybody happen to own a Cohu 355 DC Voltage Standard? I have just purchased one and I need a manual for the calibration. I could only find half of the manual online that basically just has the circuit description. Any help would be appreciated. Thanks.

author: trobbins
author_rank: Frequent Contributor
timestamp: March 04, 2024, 03:04:17 am
content: In your travels if you find any cal/circuit/service details on the 303B then I'd appreciate a PM as I haven't attempted to restore that unit yet. Kintel is the other relevant search term to Cohu.

author: Solodolo47
author_rank: Newbie
timestamp: March 04, 2024, 07:43:43 am
content: There is actually a manual for the 303B on ebay for 20 dollars. It t should have service info in there. The seller also has other Cohu manuals but unfortunately not for the 355. I'm tempted to buy the manual to see if I can use its calibration info for my 355. The controls are the same but laid out in a different configuration. I assume the circuitry would be somewhat similar .

author: bnz
author_rank: Regular Contributor
timestamp: March 04, 2024, 11:16:37 am
content: I had a COHU 355 and manual but sold it. I still have a scan of the manual (no original print just an old copy) which I just uploaded to KO4BB. It is available there at recent uploads:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=07_Recent_Uploads

author: Solodolo47
author_rank: Newbie
timestamp: March 04, 2024, 10:39:49 pm
content: Thank you very much bnz!! I really appreciate uploading the manual

author: trobbins
author_rank: Frequent Contributor
timestamp: March 27, 2024, 01:24:23 pm
content: I was able to confirm the Cohu 303B electronics were significantly different to the 324, and the 355 models (from their service manuals), so if anyone has a scan of the 303B schematic I'd appreciate a PM to assist some careful rejuvenation of the e-caps and confirming the all-valve electronic sections are operating as intended.This 303B has an ovenised reference 7817039-001, and uses a Stevens-Arnold CH-801 DC-AC chopper. The 7-decade feedback resistor network has the 12 largest resistors using their own CONELCO 0370L-2 trimpot. The 1400V raw HVdc uses a large oil-can cap, rather than the latter models that went for a series string of 450V e-caps.It's interesting that the 303B, from circa 1964, was bested at that time by the 304 model.
MET/CAL Procedure Writing - Page 1
Forum section: electronics / general

author: moosebiscuit
author_rank: Contributor
timestamp: March 21, 2024, 01:36:43 pm
content: Good morning everybody,I am trying to incorporate some new standards and test equipment that we do not currently have MET/CAL calibration procedures for. I don't have the thousands of dollars to get the fluke seminar/training, and I have been reading up on the syntax and everything, but I am still a little bit lost. I am familiar with automation using Python, but I would like to get into building METCAL procedures for standardization in my lab. I know this is a broad question, but I would like to get a basic understanding of what is going on. I understand that there are sub-procedures that are linked to the main procedure, but I'm not really sure how to go about writing my own. I am used to a linear script based approach, but the subprocedures kind of throw me for a loop. For example, I have many E3600 series power supplies that I would like to use a 8845A/8846A DMM and a Tek MDO32 oscilloscope as standards. Unfortunately, I don't have anything to reference to for these models regarding MET/CAL procs. Any guidance would be appreciated, thank you.

author: RYcal
author_rank: Contributor
timestamp: March 25, 2024, 09:18:57 pm
content: There are FSC's for the 884X series DMMs built in. If the Oscope has a comm port then you could get that talking via MET/CAL as well.I have offered training in the past at a far better rate than Fluke and I tailor it to suit the client's needs.
Help a Precision Metrology Amateur Understand ADRMU LTZ1000A Voltage Reference - Page 1
Forum section: electronics / general

author: ZGoode
author_rank: Frequent Contributor
timestamp: January 22, 2024, 09:13:23 pm
content: Hello Fellow Metrology Geeks,I'm looking to replicate a version of Marco Rep's ADRMU and wanted to make sure I am reading his schematics correctly. If I am understanding correctly, I need to populate the correct resistors in the configuration arrays shown on page two. Whereas, all the other parts shown on pages 1, 3, and 4 do not change depending on LTZ/ADR configuration.Is this understanding correct? I just want to make sure I am not focusing my time doing math for sections that need no or minimal calculations to setup.

author: chuckb
author_rank: Frequent Contributor
timestamp: January 26, 2024, 03:25:46 pm
content: In general that is correct. However on page four you have a gain stage at U401. The gain will be different when using the LTZ1000 (7.14V) verses the ADR1000 (6.6v).If you are laying out a new PCB I would change the page two 0.1u capacitors (C201, C203, C204) from 0603 X7R to 1206 C0G. They will have 100x less current noise.On page 2, capacitor C204, LTZ1000 factory recommends 22nF, ADR1000 recommends 100n.Good luck!

author: ZGoode
author_rank: Frequent Contributor
timestamp: March 23, 2024, 08:09:18 pm
content: Thanks for taking the time to respond!I am looking to use his board as is for my first attempt at a voltage reference before doing my own board layout. I have found some 0704 C0G 0.1uF capacitors as you suggested for C201/3 and a 22nF C0G 0805 for C204.Also, thanks for catching the gain thing. I knew the LTZ1000 had a different voltage than the ADR1000, but forgot to account for that with the OPAMP. Looks like the OPAMP is using the resistor network which I still need to do the math for.
Triax connectors/cables free to a good home - Page 1
Forum section: electronics / general

author: Sengcid
author_rank: Regular Contributor
timestamp: March 22, 2024, 12:37:55 am
content: BNC style panel mounting, four of each. You pay postage.Edit: These are of the older "two-lug" type, apparently. The central and first screen have lugs. The outer screen and connector shell are usually connected to local 0V ("earth") via the panel. One could use an insulating washer and washer/lug if required.If interested pls pm me.

author: EC8010
author_rank: Frequent Contributor
timestamp: March 22, 2024, 05:28:02 pm
content: You have a PM.
Oscilloscope HM204-2 - Page 1
Forum section: electronics / general

author: RETRAITE
author_rank: Newbie
timestamp: March 14, 2024, 03:52:24 pm
content: Bonjour,J'ai en charge la remise en état d'un oscilloscope de marque Hameg référence HM204-2.Il présente une erreur d'environ 1V en amplitude sur les deux canaux, tout en sachant que cette valeur n'est pas identique sur les deux canaux.Je ne trouve pas sur le schéma le ou les réglage pour résoudre ce problèmeComptant sur votre aide,Cordialement,Alain

author: RAPo
author_rank: Super Contributor
timestamp: March 14, 2024, 04:38:49 pm
content: Dezelfde 1V op elk kanaal?(translation: the same 1V on each channel?)

author: Simon
author_rank: Unknown
timestamp: March 15, 2024, 07:10:00 am
content: This forum only accepts postings in English please. Google translator is quite good.
Temperature Stability of PTC Heater - Page 1
Forum section: electronics / general

author: Chance92
author_rank: Regular Contributor
timestamp: September 16, 2022, 01:42:33 am
content: There are PTC heaters out there designed to produce a constant temperature. I wonder if anyone has any experience with their stability? For example, if the environment temperature rises from 15C to 25C, how much will the heater temperature change?

author: MK
author_rank: Regular Contributor
timestamp: September 16, 2022, 04:25:03 pm
content: A lot depends upon the insulation you put around it.

author: Birb
author_rank: Contributor
timestamp: March 13, 2024, 02:14:29 pm
content: Probably also depends on the steepness of the resistance-temperature curve? But too steep might result in oscillation

author: EC8010
author_rank: Frequent Contributor
timestamp: March 13, 2024, 05:44:46 pm
content: If you need a reasonably constant (and adjustable) temperature, there are Chinese PID controllers. Five years ago, I bought two for £25. They were mains powered and included 10A solid state relay and Type K thermocouple. I grafted one into a tabletop oven to make a cheap temperature cabinet accurate to 2C (confirmed by separate measurement), stable to 1C. I later added a computer fan blowing downwards to stir the air up and keep temperature constant throughout the oven space.SWMBO bought an air fryer yesterday. It uses a small induction motor to drive its fan and there looks to be enough room in the upper housing to fit a PID controller...

author: Birb
author_rank: Contributor
timestamp: March 14, 2024, 07:53:11 am
content: The problem is the pid controller is a bit bulky and may be a bit larger when an enclosed system is designed. Also, variable temperature may not be needed. I believe the original intention was to have it act as a an all in one solution for heating at a near constant temperature?
White Paper - Optimizing Chopper Amplifier Accuracy - Page 1
Forum section: electronics / general

author: miro123
author_rank: Frequent Contributor
timestamp: March 19, 2024, 08:51:21 pm
content: I found this paper interesting because I manly use TI chopper amplifiers.It cover some aspects of using modern chopper amplifiers.https://www.ti.com/lit/wp/sboa586/sboa586.pdf?ts=1710795997421&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FOPA182
Genrad Sound level meters 1565-A - Page 1
Forum section: electronics / general

author: jonpaul
author_rank: Super Contributor
timestamp: March 12, 2024, 01:29:05 am
content: Bonjour a tous:Just received some General Radio 1565-A circa 1960s..1970s. One has the ceramic mic element missing and 2 have a longer MIC than the third.Have 3 original GenRad leather cases. No battery damagesAll sort of work. But one broken meter face,Adjusting CAL pot. with GenRad 1562A sound level calibrator these all read low 10..20 db,What's suspect, the old ceramic mic elements or just usual transistors, caps, resistors, pot, switches ?Also not obvious in manual how to open the case for service.Any ex GenRad, or noise reduction or acoustic experts here?Many thanksJon

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 12, 2024, 04:55:03 pm
content: You can download the manual online. It tells how to disassemble. The ceramic mics are usually functional, but might have lost some sensitivity. I have quite a few and it's sort of a crap shoot when buying them because nobody can correctly test them. The meters can be subject to the usual component drifts and failures. It uses an oscillator circuit to raise the battery voltage to something like 22 volts. Make sure that's working correctly. The input is an FET that could also be damaged, but probably not. Do you know that your calibrator is correct?

author: jonpaul
author_rank: Super Contributor
timestamp: March 12, 2024, 06:00:08 pm
content: Dear Conrad! Many thanks for the tips: Much appreciated as you are the only one to respond!1/ Was aware of the 22V inverter, will check that first.2/ My lab has 3 pcs of thefine 1982 GenRad precision sound levbel meter, and good 1562A, all are calibrated and agree.3/ Have the PDF manual, seeking a hard copy and a plastic GenRad meter face.4/ Think FETs are OK but will test all, the manual has needed info, voltages.5/ I will contact our old friend, Nolan Lewis at ACO Pacific, ham and ex B&K (?) a super microphone expert.Have a great day!Jon
Allan deviation algorithm - Page 1
Forum section: electronics / general

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: February 28, 2024, 10:45:59 pm
content: I'm interested in programming a Teensy4.1 to output the Allan deviation of the voltage that is being monitored.Is it feasible?If so, does anyone have code for it?Thanks,Randall

author: Kosmic
author_rank: Super Contributor
timestamp: February 28, 2024, 11:13:13 pm
content: Quote from: RandallMcRee on February 28, 2024, 10:45:59 pmI usually search in github to get some ideas.Exemple:https://github.com/topics/allan-varianceThis one look easily portable to a Teensyhttps://github.com/SMAC-Group/avarEdit: Ha just noticed they don't use STL libraries. You might want to chose another one.

author: jfet
author_rank: Contributor
timestamp: February 29, 2024, 01:20:56 am
content: The math is well documented at NIST time and frequency section. Bill Wrilley wrote a book , its on his web sitehttp://www.stable32.com/that documents time measurements. That is were Allan deviation came from David Allan at NIST.http://www.allanstime.com/

author: Kosmic
author_rank: Super Contributor
timestamp: February 29, 2024, 01:54:51 am
content: The original article from Mr AllanAllan, David W. 1966. “Statistics of Atomic Frequency Standards.” Proceedings of the IEEE 54 (2): 221–30.https://tf.nist.gov/general/pdf/7.pdf

author: cncjerry
author_rank: Unknown
timestamp: March 01, 2024, 04:51:53 am
content: I think Tom Van Bak did a version of the code as well. I have the code, can't remember if I converted it to Visual Basic or did that app in C. Ping me if you get stuck.

author: edpalmer42
author_rank: Super Contributor
timestamp: March 01, 2024, 07:11:15 am
content: Note that Dr. Allan's work has been updated a few times.So now, there's:1. Allan Deviation - which almost no one uses anymore.2. Overlapping Allan - very common. This is now considered the 'standard' version.3. Modified Allan and its overlapping version.4. Total Allan and its overlapping version. This is my favorite because it gives you a longer graph than any of the other versions for a given dataset.There are others beyond that such as Hadamard and Theo 1.Each version tends to inflict a heavier computational load than the ones earlier in the list.A few programs that use Allan Deviation and some of its offshoots are Timelab, Stable32, Plotter, and Alavar. Timelab is updated regularly, Stable32 and Plotter are not. I'm not sure what the status of Alavar is.Ed

author: miro123
author_rank: Frequent Contributor
timestamp: March 02, 2024, 06:09:42 pm
content: There many way to do it on Teensy 4.11. C / C++ code2. micropython and import allantools.More documentation including the python implementation on link below. I gues that python implemrntation is just a python writer on C++ library. It is low footprint and fasthttps://allantools.readthedocs.io/en/latest/functions.html
KS-24019 RFTGm-II-XO need pinouts pinouts - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: February 27, 2024, 09:02:37 pm
content: Hi, Have a few of these that have been sitting around.I'd like to power them up and see what happens.The only pinouts I could find referenced the RFTG-m-XO mine are the RFTGM-II-XO.Are the pinouts different?I'm just needing the power connections for now.Cheers,Corby Dawson
Current comparator /wiring  interesting book  - Page 1
Forum section: electronics / general

author: Overspeed
author_rank: Frequent Contributor
timestamp: March 07, 2024, 08:29:20 pm
content: Helloan interesting book on the subject current comparator and transformer wiringThe current comparatorby Moore, W. J. MPublication date 1988Publisher London : P. PeregrinusRegardsOS

author: EC8010
author_rank: Frequent Contributor
timestamp: March 08, 2024, 05:23:45 pm
content: I'm always a sucker for an interesting book so I looked it up. £68 for 132 pages! (25% off for IET members) And you can't even view a sample page or three. I lost interest.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 14, 2024, 03:06:44 pm
content: Remove the txt extension and download both files. Collect a zip archive.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 14, 2024, 03:10:59 pm
content: File 2
Optical clocks and the second redefinition - Page 1
Forum section: electronics / general

author: iMo
author_rank: Super Contributor
timestamp: December 05, 2023, 08:45:14 pm
content: Optical clocks with 1E-18 uncertainty..

author: Gyro
author_rank: Super Contributor
timestamp: December 05, 2023, 10:06:33 pm
content: 56:55... Damn, where did the Ytterbium ion go?!Impressive stuff.

author: Electrole
author_rank: Contributor
timestamp: February 26, 2024, 07:21:25 pm
content: An open access paper was published on January 22, 2024, on the "Roadmap towards the redefinition of the second":https://iopscience.iop.org/article/10.1088/1681-7575/ad17d2Quite an interesting review of things to consider should we decide to redefine the second (and yes, we eventually will / should... it's more a question about "how").Happy reading!
Transfer std 1Ohm - Page 1
Forum section: electronics / general

author: Sengcid
author_rank: Regular Contributor
timestamp: February 26, 2024, 03:45:59 pm
content: Free to a good home. Pls pm if interested.

author: bastl_r
author_rank: Regular Contributor
timestamp: February 26, 2024, 04:43:10 pm
content: Send PM