hybridfree/eevblog-posts huggingface dataset:
farnell LS30-10 electric scheme, mising parts - Page 1
Forum section: electronics / repair

author: poikka
author_rank: Newbie
timestamp: April 09, 2017, 07:29:34 am
content: HelloI get farnell LS0-10It dosen´t work at all, because ita seems there is missing some parts. (See photo attached)List of missing parts:C1, C5, C12, C46, C41, C50 T1, SW5, R11, R69, R70Can someone give me advice, there I can find electric scheme of this device? Or if smbd have the same one, can you provide me some photos/info about missing parts?Thank you

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 09, 2017, 09:03:31 am
content: There are photos herehttps://www.eevblog.com/forum/testgear/farnell-ls30-10/msg787850/#msg787850google "LS30-10 Schematic" finds a few hits - I have the full manual but schematic is 1 page A4 so not very clearFrom the parts listC1 47n 250VC5 1u 25VC41 470u 40VCan;t see C46 in listC12 ,R11 , C50,R69,R70 not fittedSW5 is voltage select - suggest you just hardwire this.230V is towards front panel

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: April 09, 2017, 09:16:37 am
content: Judging by the fact that those holes seem to be clean, I'm gonna guess they were never meant to be fitted, or for some other versions, like Mike says.if you can't find any schematics, best way to approach this would be to just look at how the device seems to be built and measuring some sensible points for voltages, as a start (ie, verify that voltage regulators are outputing the right voltages, check the voltages accros capacitors).Of course, always do a visual check, and see if there are no black/other odd color marks on the pcb and/or components.
Help with the repair of an IBM 5150 Personal Computer - Page 1
Forum section: electronics / repair

author: teddy06550
author_rank: Newbie
timestamp: April 07, 2017, 05:38:19 pm
content: Hey all i recently bought a 1985 ibm 5150 that would not POST at all with the hopes of repairing it and getting it working with no luck so far. I have checked that the power suply is providing all the correct voltages and it is but still nothing, have tried piggybacking ram to see if that helps but nothing and wondering if anyone knows what to check on these older computers (the caps are fine as the test for these is to see if the power suply overloads which it does not) i do hear a crackling on the speakerThanksEd

author: james_s
author_rank: Super Contributor
timestamp: April 07, 2017, 06:55:09 pm
content: The first thing I'd check with any computer of this era after the power supply is the CPU clock generator and reset line. While not a PC, I've fixed a few Gottlieb arcade game boards that are 8088 based and more than once I've found a bad octal bus transceiver, the 8088 has a multiplexed address/data bus so if the chips that handle this are bad, not much will happen. If that all looks good, you might have bad RAM or a bad BIOS ROM.

author: teddy06550
author_rank: Newbie
timestamp: April 07, 2017, 07:48:40 pm
content: Hi James_show would i test clock generator and reset line without an oscilloscope as i dont have oneEd

author: james_s
author_rank: Super Contributor
timestamp: April 07, 2017, 08:36:03 pm
content: Well you could use a logic probe, or in a pinch a DMM may be of some use. You will need some sort of test equipment though, with nothing you are flying blind and just guessing.

author: orbanp
author_rank: Regular Contributor
timestamp: April 08, 2017, 02:22:58 pm
content: Hi Ed,Here is a link to the hardware reference manual, that should get you going:https://www.manualslib.com/download/819833/Ibm-5150.htmlGood luck, Peter
Tek 2710 Spectrum Analyzer with error message: "counter hardware failure" - Page 1
Forum section: electronics / repair

author: baumfred
author_rank: Newbie
timestamp: April 07, 2017, 12:27:34 pm
content: Hello,I have here a Tek 2710 spectrum analyzer with error message: "counter hardware failure".This message is not listed in the user- or service manual.Does anybody knows what this means?The analyzer is otherwise in running condition, but the displayed frequency (at about 100Mhz) is 7 Mhz to low.Thanks, baumfred
852d+ Cheap Repro Proactive repair questions - Page 1
Forum section: electronics / repair

author: MrWizerd
author_rank: Contributor
timestamp: April 04, 2017, 07:25:49 am
content: So I have the 852D+ Rework station (hot air and solder) I had got it for very cheap and I have done some reading and once got a search to work and give me some threads on here that eluded to the possibility that someone somewhere is working on replacement boards that are uC based. I can not find them and if anyone knows where they may be or has a link to a project page that I can read up on I would greatly appreciate it. That being said I apologize for this post as I know that it is probably drudging up things that have been posted before but as I said the search function would just not work for me no matter what I tried keeps saying report to the admin. I will likely do so if it persists. My current plan is as followsMake sure unit is properly grounded and fused.Add a switch that will cut power to the unit so I can turn it off all the way after the cool down cycle (to prevent random triac failures)Do a general safety check and repair anything that appears completely unsafe that is in my power to fix,And make sure that transformers and such are all properly secured.There are a few other things I am sure to run into. I did however have a question, some of the things I have heard is that the 8A TRIACs the bt137https://www.digikey.com/product-detail/en/ween-semiconductors/BT137-600,127/1740-1026-ND/1154768tend to blow out. I found some BTA12's that are 12A TRIACshttp://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=222825388&uq=636257350278275154though the gate trigger voltage on these is 1.3V instead of 1.5V my thought was that I could use these possibly as it has been suggested by some they are being driven almost at 100% current limit and thus are over heating. I thought changing them to a higher current rated one may help with that but I don't know much about TRIACs and if this is a possible solution.I suppose that question is a mute point if anyone has a set of replacement boards and firmware for said boards for this in the works, especially if I can help with the testing for such items, I can have the boards printed and build them up and get to testing it out, but I can not find anything when I search or 852D+ rebuild or DIY replacement or any other way I thought to search.Anyone have any ideas, suggestions, links?Again I apologize for not being able to just use the search fuction.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 06, 2017, 02:32:17 pm
content: https://www.amazon.com/dp/B00QIGJSF8?psc=1
Fluke 415B schematic - Page 1
Forum section: electronics / repair

author: FTM777
author_rank: Newbie
timestamp: April 05, 2017, 03:29:53 pm
content: HiAnyone have a schematic for the Fluke 415B? I have found the manual on-line but they do not have the schematics with them.Nick

author: dacman
author_rank: Frequent Contributor
timestamp: April 06, 2017, 01:00:36 am
content: ATEC has a schematic.http://www.atecorp.com/products/fluke/415b

author: FTM777
author_rank: Newbie
timestamp: April 06, 2017, 12:24:30 pm
content: Thank you dacman for that link, I had downloaded every copy of the manual I could find but they all were missing the schematics. So once again thank you.Nick
HP 6624A overvoltage when disabled - Page 1
Forum section: electronics / repair

author: Vicus
author_rank: Regular Contributor
timestamp: April 01, 2017, 02:23:37 pm
content: I try to repair an HP 6624A with 3rd channel that when disabled say overvoltage. If the output is enabled no problem but only if the voltage is set over 1.9V. If the voltage is set under 1.9V the voltage out is clamped to about 0.6V. I try to follow the guide in the service manual without any result. Some idea?Here the schematic:http://literature.cdn.keysight.com/litweb/pdf/5989-6871EN.pdf?id=1268102Here the service manual:http://ridl.cfd.rit.edu/products/manuals/Agilent/power%20supplies/CD1/Service/6621Aser.pdf

author: pelule
author_rank: Frequent Contributor
timestamp: April 01, 2017, 05:01:05 pm
content: Have you connect the sense line?/PeLuLe

author: Vicus
author_rank: Regular Contributor
timestamp: April 01, 2017, 05:34:30 pm
content: Yes, I try also to remove the link and the psu have the same behavior. Only difference is in output precision.

author: Vicus
author_rank: Regular Contributor
timestamp: April 05, 2017, 03:29:07 pm
content: I found that the two problema (overvoltage when disabled and at low voltage) are the same because disable the output is equal to put the CV at 0V.The serial number is 3222A07337, no option installed.I check rail voltage and they are good. Check signal voltage and are ok. Vref ok. DAC ok. Now I need to know how work the rest of the circuit.

author: Samogon
author_rank: Frequent Contributor
timestamp: April 05, 2017, 03:57:17 pm
content: Just in case, check OVP settings.

author: rx8pilot
author_rank: Super Contributor
timestamp: April 05, 2017, 04:16:30 pm
content: I have the same unit, very similar problem. Joining the conversation......Sent from my horrible mobile....
VC99 multimeter - adjusting - Page 1
Forum section: electronics / repair

author: akis
author_rank: Frequent Contributor
timestamp: April 05, 2017, 10:05:50 am
content: HelloI blew a fuse on my VC99 multimeter and while trying to remove the old fuse I accidentally broke a pot on the board, it is labelled VR5. Could anyone please supply me with a schematic or manual to explain how to adjust this pot?Many thanks

author: RayRay
author_rank: Frequent Contributor
timestamp: April 05, 2017, 10:35:44 am
content: Could you provide a picture of the circuit board?Which exact VC99 is it? There are quite a few different manufacturers (Vichy/Vici/Victor) and they're all built a bit differently.Was the VR a full metal one, or did it had a piece of plastic on it? Does it have any numbers on it (or on the broken piece)?

author: akis
author_rank: Frequent Contributor
timestamp: April 05, 2017, 11:01:08 am
content: I have closed the multimeter now. The VR is not broken (badly) it was plastic with a metal top, I managed to put it together, and turn it left and right a few times. I just need a schematic or a "calibration" manual I suppose
Tek 2232 horizontal image distorted, turned out to be a simple repair [Solved] - Page 1
Forum section: electronics / repair

author: Satbeginner
author_rank: Regular Contributor
timestamp: April 05, 2017, 08:43:59 am
content: Hi all,I got my hands on a 2232, that had a compressed horizontal display.Vertical was OK.I first checked all the Power Supply voltages, and they were all OK, so I went to the horizontal amplifier.There the 100V was OK too, but since the picture was compressed, but centered, I figured it had to be something both the amps were suffering from.I had a better look at the voltage divider that provided bias for both amps, R792 and R793.R792 was spot-on 5k36, but R793 measured (in circuit) way to high.I removed R793 (difficult because of the High Voltage cable running on top of it-) and it was gone... completely open!!I replaced it with a bigger metalfilm 1/4W resistor I selected to be 56k2 et voila: Succes!!I think this resistor was dimensioned way too small to be used in a 100V circuit, but who am I to judge....Un saludo,Satbeginner (Leo)
TDS544A - misaligned floppy drive - can be fixed? - Page 1
Forum section: electronics / repair

author: John_ITIC
author_rank: Frequent Contributor
timestamp: March 29, 2017, 02:18:51 am
content: My TDS544A can only write to the floppy if it was formatted in the TDS544A. But then the files cannot be read on my PC. If formatting the floppy in my PC, the TDS544A can't write to the floppy. The track alignment must be off in the TDS544A. Can this be fixed or do I have to buy a replacement floppy drive on Ebay?Thanks.

author: Jwalling
author_rank: Unknown
timestamp: March 29, 2017, 10:01:14 am
content: In the old days of 8" floppy drives you would use a special disk and an oscilloscope to align drives. I remember doing this back in the 80's on Shugart and Qume drives. The scope would show a cats eye and you would turn the motor until the lobes were of equal size.www.myatari.com/dymekalign.pdfThere is a screw that holds the motor that drives the heads in place. If you loosen the screw you could try using a disk formatted on your PC and turning the motor CW or CCW until the scope can read the disk properly.

author: CJay
author_rank: Super Contributor
timestamp: March 29, 2017, 01:21:17 pm
content: I would assume you've tried more than one PC floppy drive?It's rather important to know which drive is out of alignment or you could end up with a pile of disks only you can read.Those alignment disks, I remember them along with the floppy exercisers that made alignment much easier and on 5.25" and 3.5" drives.Technology used to be so serviceable and actually fun to work on.

author: tombi
author_rank: Regular Contributor
timestamp: April 02, 2017, 02:29:38 am
content: Depending on how original you want to keep the device, I wonder if a floppy emulator might be a better solution? Something like thishttp://www.ipcas.com/products/usb-floppy-emulator-fdd-to-udd.html

author: edpalmer42
author_rank: Super Contributor
timestamp: April 02, 2017, 03:01:59 am
content: The first thing to do in a case like this is clean the heads of all the drives, both the scope and the PC. For this, you need to find a floppy cleaning disk. If there's no cleaning fluid with it, just use a drop or two of isopropyl alcohol.If cleaning doesn't cure the problem, as CJay said, you need to make sure that the suspect disk is the one that's out of alignment. Since alignment disks are impossible to find, the next best choice is an installation floppy for some software package. Those floppies had a reputation for being cheap since they were often only used once. Try a few. They should be readable on both drives.Ed

author: John_ITIC
author_rank: Frequent Contributor
timestamp: April 05, 2017, 02:10:14 am
content: No, it's definitely the floppy drive that's out of alignment. There is one of Ebay for $50 and the USB adapter ones are about the same. Before buying, I'll have to open the enclosure to see if it can be adjusted (low priority since lots of other scopes to use, really).Thanks.
Druck UPS III Loop Calibrator fault - not measuring inputs - Page 1
Forum section: electronics / repair

author: Greg981
author_rank: Newbie
timestamp: April 04, 2017, 06:25:45 pm
content: Hi,I have a Druck UPS III loop calibrator which will give mA output but reads zer for both current and voltage in. I've had a look over the boards inside, and not found anything of note, then put it back together making sure that the board to board connectors are fully mated. Don't know where to go from here. Has anyone seen this before? Circuit diagrams? Any help appreciated, thanks.
troubles with tektronix scope - Page 1
Forum section: electronics / repair

author: Dirceu
author_rank: Newbie
timestamp: April 03, 2017, 07:33:08 pm
content: Hi to all.I have a TDS684B scope presenting a "vibrating" waveform. It is in vertical and horizontal directions, as another signal were added to original one. This happens in 4 channels.--in self test it pass, no message errors or fails;--this shake appears to be more intense in higher frequencies input signals;--without input signal the horizontal trace is fixed;--this shake is randomly, not a repetitive pattern;-- the 25 volts power supply is presenting a ripple as noise-it reaches 0,5Vpp sometimes. The other supllies are OK. I did not find yet the reason for this ripple in the 25 volts psu, it seems to be in the first rectifier/multivibrator part. Capacitors are OK.--there is no schematics.Anybody has a tip to help me?Thank you in advanceDirceu

author: james_s
author_rank: Super Contributor
timestamp: April 03, 2017, 07:53:34 pm
content: The power supply ripple is the first thing I'd check. There is a component service manual out there for one of the 5xx series scopes which should be close enough to help you. Is this one of the era that has leaky SMD capacitors all over? If so then you'll want to replace all of those. Later TDS scopes switched to ceramic chip bypass capacitors.

author: Armadillo
author_rank: Super Contributor
timestamp: April 04, 2017, 04:32:34 am
content: Try temporary disconnect the fan and measure again.
Agilent 34401a newer version (round button) schematics needed - Page 1
Forum section: electronics / repair

author: openloop
author_rank: Regular Contributor
timestamp: April 02, 2017, 08:22:34 pm
content: Main board revision 003. Part: 34401-66511Problem: they've replaced that famous dual JFET U104 in DC input amplifier with OPA130UA op amp (in my case it's blown somewhat). Widely available service manual does not reflect this alteration.Web search was only partially successful: I've found this page (at very bottom):http://bbs.38hot.net/thread-17402-1-1.htmlIt's hard to read and it looks like it's a product of reverse engineering...So, does anybody have a fresher version of the schematics?

author: Vicus
author_rank: Regular Contributor
timestamp: April 03, 2017, 11:41:01 am
content: I'm not shure about the question but I found:http://literature.cdn.keysight.com/litweb/pdf/34401-90013.pdf?id=765594U104 is a dual jfet and the datasheet seems to be this one:http://www.vishay.com/docs/70247/70247.pdf

author: openloop
author_rank: Regular Contributor
timestamp: April 03, 2017, 08:31:32 pm
content: Maybe I wasn't clear.To put it another way: there are no dual JFETs on that version of mainboard. Agilent/Keysight redesigned that part of the device, but didn't bother to update the service manual with new schematics.
Reed Switch stuck closed - Page 1
Forum section: electronics / repair

author: AlexMA
author_rank: Newbie
timestamp: April 03, 2017, 03:18:29 am
content: I use a "Thermalarm" to detect too high or too low temperatures in the greenhouse environment. It uses reed switches (Hamlin/Littelfuse 59025) mounted on the high and low set temperature arms, activated by a small magnet which is mounted on the thermometer (current temp) arm. Works great. Reed switches are well suited to the greenhouse environment, which has high humidity and lots of bugs/spiders.For years, we wired the Thermalarm through a relay to a siren to warn us of high/low temps, powering the circuit with a 12v automotive battery. This year, I realized we have 120V outlet at same location and that we could use a 120VAC to 12VDC transformer wall plug. I did so, but found a problem with the relay (spiders). Then I thought maybe the relay was unnecessary.I ran a 30 watt load through the Thermalarm which is rated for a 10 watt maximum load. I ran this load for several seconds. The switch now seems to be stuck closed. Is this likely to be a permanent failure of the reed switch? Or, is it repairable?I have considered mechanically tapping the switch, applying a current of the opposite polarity to the switch, or waving a magnet in the vicinity of the switch. Not sure whether any will work.... Any thoughts most welcome. Thanks.Al

author: edavid
author_rank: Super Contributor
timestamp: April 03, 2017, 04:54:29 am
content: It's not uncommon... you welded the reeds together. Replace it.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 03, 2017, 05:03:51 am
content: Occasionally tapping the relay will break the weld and restore it for a while. Low percentage success. Contacts will be scarred, so future life is uncertain. Replacement is the right option. Unfortunately reed relays aren't as cheap as they once were.

author: edavid
author_rank: Super Contributor
timestamp: April 03, 2017, 05:32:22 am
content: Quote from: CatalinaWOW on April 03, 2017, 05:03:51 amIt's not a relay, it's just a packaged switch, of the type that was commonly used for burglar alarms in the past:http://www.mouser.com/ProductDetail/Hamlin-Littelfuse/59025-030

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: April 03, 2017, 12:44:34 pm
content: Reed switches don't like being tapped; they don't even like having their leads cut with cutters because the G-shock transmitted damages the hermetic seal. Full flush cutters are essential.BT

author: Nusa
author_rank: Super Contributor
timestamp: April 03, 2017, 02:28:50 pm
content: 30 Watts / 12 Volts = 2.5 Amps. That reed switch is rated to switch 0.5 Amps. No surprise it failed quickly. It's toast, so if you want to try tapping it, you got nothing to lose.Even 10 Watts / 12 Volts is too much, but you may get away with that at the expense of switch life.Replace the reed switch and use a relay circuit to drive your loads next time.
Lecroy LC574A battery replacement - Page 1
Forum section: electronics / repair

author: Armadillo
author_rank: Super Contributor
timestamp: April 02, 2017, 10:54:21 am
content: Hi;Any information would be appreciated. Regarding the battery replacement, it is stated in the manual that;"The serial number of the LC574A oscilloscope is loaded in the real time clock memory which is battery backed up. If it becomes necessary to replace the processor board, the serial number must be loaded in the memory of the new board by using LeCroy program" LeCalsoft" under GPIB remote control."Hence, do I need to hook up a temporary battery before I dismantle the old battery so that the serial number is retained in the memory of the RTC?Anyone have done it before with photos would be great.Do you have a copy of LeCalsoft.exe to share.?Thank you all.Edit: I like the Lecroy HMI, somehow the screen presentation looks really pleasing and comfortable than Tektronix. My favourite amongst the scopes.

author: Armadillo
author_rank: Super Contributor
timestamp: April 02, 2017, 02:41:42 pm
content: Thanks for reading, I found the information in lecroy owners group.
Advantest R3273 spectrum analyzer problems with high spans - Page 1
Forum section: electronics / repair

author: lowtension
author_rank: Contributor
timestamp: March 25, 2017, 10:17:29 am
content: Hello,I have a R3273 with a problem displaying signals above the low band mixer 3.5Ghz with high spans over about 10 Ghz.For example, trying to detect a CW signal -10dbm at 12 Ghz on full span , signal is not detected at all on some sweep or has low amplitude on another sweep or has almost correct amplitude on another sweep (signal fluctuate up and down to noise level on different sweeps on the trace) , switching down to 10Ghz or less, signal detected correctly with correct amplitude.Changing sweep time up or down does not help. Also, changing the YTF offset values does not help either, just under about 10Ghz span works fine.Any clues what can tha be ?Thanks

author: eb4fbz
author_rank: Regular Contributor
timestamp: March 25, 2017, 01:04:22 pm
content: Check the YTF and YIG cover screws, they usually get loose over time.

author: Samogon
author_rank: Frequent Contributor
timestamp: March 25, 2017, 02:16:57 pm
content: Did you run calibration? Just in case?

author: lowtension
author_rank: Contributor
timestamp: March 29, 2017, 08:18:08 pm
content: Hello,I checked the YIG and the YTF, screws are 100% tight. Calibration does not help.But I noticed that on higher RBW like 5Mhz at higher span 10ghz- 26.5 Ghz, the problem does not exist!May be it is normal if I need to identify a signal in large spans, I need to change the default RBW from 3 MHz to 5 MHz.Also, YTF is tracking great at all frequencies.Is this normal behaviour ?Thanks

author: Samogon
author_rank: Frequent Contributor
timestamp: March 30, 2017, 04:02:21 am
content: I have R3172, let me reproduce.Pretty stable on mine, but accuracy is degraded and it is normal on such big span imho.

author: lowtension
author_rank: Contributor
timestamp: March 30, 2017, 08:59:35 pm
content: Quote from: Samogon on March 30, 2017, 04:02:21 amMine jumps somtimes down 5-10 dbm on some sweeps, on other sweep can dissappear, stable also in some other sweeps. Very wierd. at 5 MHz RBW looks stable and correct amplitude. It seems that the YTF is missing with 1-3mhz and on RBW 5 MHz this fault is not noticable because of the wide rbw.I will try to look at the output of the amplifier stage of the YTF tune turrminals using a scope.Thanks for showing this.

author: lowtension
author_rank: Contributor
timestamp: April 01, 2017, 11:13:27 am
content: Checked again, I was wrong in the first post, even under 3.5Ghz problem exists in wide spans over about 10Ghz. It is not the YTF.So, what I we have here something to do only with wide spans and not related to the YTF enabled above 3.5Ghz, any ideas? thanks

author: Samogon
author_rank: Frequent Contributor
timestamp: April 02, 2017, 03:06:49 am
content: Stupid question: do you have preamplifier disabled?

author: lowtension
author_rank: Contributor
timestamp: April 02, 2017, 07:38:12 am
content: Quote from: Samogon on April 02, 2017, 03:06:49 amHello,No preamplifier option in this unit.Thanks
Duratool ZD915 Desoldering Station - Page 1
Forum section: electronics / repair

author: Beau
author_rank: Newbie
timestamp: March 20, 2017, 05:04:00 pm
content: HiI have the a problem with my Duratool ZD 915 desoldering station it will not hold the set temperature and continues to rise beyond the set point to it maximum. Has anyone else had this problem is this a known problem with the hardware or software and does anyone have a schematic/ circuit diagram...I have just repaired the SMPS but after test and rebuilding the enclosure I dropped the metal heat sink clamp on the STPS20S100CT and P60NF06 MOSFET, as I had not discharged the capasitor, bit of a crack but the SMPS still works but as above it won't hold the set point. P60NF06 ordered as this appears to control the heater in the gun, SMPS fault was a failed CQ1565RT..Any help or advice would be welcomed...Beau

author: sanman
author_rank: Contributor
timestamp: March 21, 2017, 10:51:26 pm
content: I don't have the same model but I'm working on the exact same problem on a Aoyue 968. Maybe my issue is similar and can help you.There is aTriacthat is fed from aTriac Output Optocoupler. The Triac tested fine. I found the Output Optocoupler to be bad... keeping the Triac constantly on. I replaced the Output Optocoupler and it worked fine.

author: Beau
author_rank: Newbie
timestamp: March 22, 2017, 04:21:44 pm
content: HiThanks for the reply I had the same idea and changed the optocoupler last night but no joy......it still could not hold the set point, Im still waiting for the mosfet to arrive as I think this controls the iron? As I have the SMPS back up and working I'm going to have another look at the voltages and the C- & C+ line from the control board back to the power supply that I believe controls the supply to the iron via the micro controller.As I asked in my previous post a circuit diagram would be very helpful but I suppose with this low end equipment it's hard to obtain?Beau

author: Beau
author_rank: Newbie
timestamp: April 01, 2017, 06:14:31 pm
content: I have managed to repair my desoldering station It was the MOSFET as suspected.Beau

author: stevelup
author_rank: Regular Contributor
timestamp: April 01, 2017, 07:01:49 pm
content: We've had two of these self-destruct in the same way. One of them was left unattended and it caused the whole soldering iron handset to melt...They are in the bin now!
Home built uCurrent trouble shooting. - Page 1
Forum section: electronics / repair

author: ja421
author_rank: Contributor
timestamp: May 14, 2016, 03:59:34 am
content: My uCurrent died (I think from over taxing it) -- I emailed Dave & got some tips on what to look at it, and replaced those parts - it was still dead so I decided to build my own (using his board & parts list) (FWIW: the original unit read 2.5volts on nAmp range -- I replaced a resistor & both max4239's)Testing went well for mAmp & uAmp testing -- however, nAmp; w/o anything attached/connected - it shows a voltage (between 8 and 12 mv); I hooked it up to a cheap oscilloscope & it showed some volts (as expected) but as I put my finger close to (but not touching) the current-input posts, the reading fluctuated, a lot. (I also list the parts I varied from, or had to pick myself)The uCurrent seems to work properly otherwise, but having a reading w/ nothing connected is a little disheartening. If I short the posts, it reads zero as expected. (Shorting with either the switch set to short or using a wire) Unshorting causes the volts to jump back up.The voltage generally is around 10mv and goes up / down from there.Any suggestions/thoughts on what might be wrong?Thanks.

author: JDW
author_rank: Frequent Contributor
timestamp: March 29, 2017, 09:26:29 am
content: It's been 10 months since your post. Did you ever fix the problem?

author: ja421
author_rank: Contributor
timestamp: March 29, 2017, 10:48:02 am
content: Sadly, no. I suspect there are deviations in the parts that need to be accounted for... but what I don't know.

author: guenthert
author_rank: Frequent Contributor
timestamp: March 31, 2017, 04:35:18 pm
content: Quote from: ja421 on May 14, 2016, 03:59:34 amEMI. Put the uCurrent in a shielded enclosure, connect that to ground and repeat the test.

author: ja421
author_rank: Contributor
timestamp: March 31, 2017, 05:28:41 pm
content: Tried that... Went so far as to use only battery powered & went outside away from all A/C power influences and ground the box to earth...
Tektronix 11801C E5322 T1331 Errors - Page 1
Forum section: electronics / repair

author: metalhead777
author_rank: Newbie
timestamp: March 30, 2017, 03:58:13 pm
content: Hello everyone,I'm currently trying to fix a Tektronix 11801C Digital Sampling Oscilloscope.When I tried to boot it, during extended diagnostics the error "E5322" occurred.This translates to an error in (following down the rabbit hole):E: Subsystem - "Executive"5: Block - "Subsystem Comm"3: Area - "Mainframe Comm"2: Routine - "Time Base"2: Failure identity - got no information on this.according to the Error Index Code. I read this from the Scope directly, there are no tables available.The address where the error occurred is "800C00", it expected "FFFE" and got "0001".Through an online search for the error code I found this:https://xellers.wordpress.com/2014/02/26/fixing-a-50ghz-sampling-scope-tektronix-csa803/It suggests to replace U500 and U511 (battery packed NVRAMs) with alternative parts, because the communication with said NVRAMs (Hitachi HM62256B series) has an issue, which may be caused by a dead backup battery. The NVRAMs are mounted on top of a DS1213 Smart Socket, which provides battery backup for the RAM during a WRITE-process, if the supply voltage fails.I measured the battery power and got 2.9 V and 2.7 V, so this doesn't seem to be the source of this error. I still replaced the DS1213 and NVRAMs with the suggested replacement part to see if I got lucky, and the NVRAMs themselves would have been faulty.The error still occurred, as I expected, but after one or two reboots, the error "T1331" in the "Time Base" subsystem occurred. According to the service manual, this points to a static RAM battery failure:QuoteBatteries were okay, so I switched the old DS1213 with NVRAM on top back in, still got the same error.Also from the service manual:QuoteSo I exited the diagnostics, in case I interrupted any NVRAM memory testing. I waited for about a day, and then turned the 11801C back on, and got "E5322", again.So I'm pretty much where I started. And I didn't find any other solution online.This leads to my question:Does anybody have an idea how to fix this or what else to try? My search didn't get me any schematics or extended trouble shooting routines, and Tektronix appareantly doesn't want to give them away.The service manual wasn't helpful, the programmer manual either.Thanks in advance for any help

author: Testtech
author_rank: Regular Contributor
timestamp: March 30, 2017, 10:23:31 pm
content: Go to Ko4bb.com, Manuals, Tektronix, 11801 Factory Diagnosis Manual.This should have enough to get you going on the right path.

author: metalhead777
author_rank: Newbie
timestamp: March 31, 2017, 08:22:04 am
content: Thank you, this looks promisingI'll post again if I got lucky.
Beha Telaris 0100 plus - Page 1
Forum section: electronics / repair

author: ahoyle2
author_rank: Newbie
timestamp: March 30, 2017, 10:59:49 pm
content: Hi AllI have a multi function meter (the type you use to test domestic wiring etc.) Unfortunately it has become unreliable. I would like to have a go at fixing it but all I have is the user manual. Does anyone have a schematic and/or the service manual for it. The details are;Beha Unitest telaris 0100 plusAny help would be appreciated.
Mystery Resistor Marked CR W ED - Who Made It? - Page 1
Forum section: electronics / repair

author: KJ-90
author_rank: Contributor
timestamp: March 30, 2017, 02:28:25 pm
content: I have a Simpson 379 battery tester made in the late 1960s that has what appear to be some precision metal film resistors, but I'm not sure. The resistors are sky blue, and have the following symbol:___ ___CR W EDThe top line connects to the letter W on either side, but I can't draw it here. I could post a picture though.

author: bktemp
author_rank: Super Contributor
timestamp: March 30, 2017, 03:24:10 pm
content: Maybe Welwyn?http://www.ttelectronics.com/welwynTheir current logo looks different, but it probably has changed since 1960 and they print W on most of their resistors.

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 30, 2017, 06:27:54 pm
content: Quote from: bktemp on March 30, 2017, 03:24:10 pmInteresting. Your comment made me search for Welwyn components logo, which eventually brought me to a page with historical information about the company. Seems that they associated with Worcester Royal Porcelain in WWII and eventually became a subsidiary of them. And guess what, one of the logo's of this porcelain company looks a lot like a W with the top lines. I don't think that is a coincidence
Finding Triad TY-83,84, & 85 DC-DC Converter Transformers - Page 1
Forum section: electronics / repair

author: KJ-90
author_rank: Contributor
timestamp: March 30, 2017, 02:24:07 pm
content: I was wondering if anyone knows of a source for the well-known Triad TY-83, 84, and 85, DC-DC converter transformers. They were a sealed "hockey puck" or "cup casing" transformer that produced rather high voltages and currents from 12.6 VDC. The TY-83 had an output of 500 VDC at 250mA, the TY-84 was 600 VDC at 200mA, and the TY-85 was 600 VDC at 350mA. Sometimes these units show up on eBay. Does anyone know of a source?
Looking for Kepco RCW48-15K service manual. - Page 1
Forum section: electronics / repair

author: Lodestar
author_rank: Newbie
timestamp: April 02, 2017, 06:16:48 pm
content: Hello. Does anyone have a Kepco RCW48-15K service manual? I would like to figure out how I can modify the output to be 24v. Thank you.
Modern replacement for a N8280A or SN74176N IC chip - Page 1
Forum section: electronics / repair

author: dlucy67
author_rank: Contributor
timestamp: March 30, 2017, 04:12:27 am
content: I'm diagnosing a Itron (Newport) 650 NIXIE tube based counter and I'm trying to find a modern replacement for the decade counter chips in the Itron. They are labeled N8280A and I can find a replacement chip of SN74176N, that, too, is now obsolete.Anyone know a pin-compatible replacement for the N8280A?

author: edavid
author_rank: Super Contributor
timestamp: March 30, 2017, 04:42:16 am
content: 74196 or 74LS196 will also work. All of these parts are obsolete, but available on eBay.NTE74176 is actually still available from Newark.
TTI EX4210R - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: February 21, 2017, 11:57:02 am
content: Hello everyone! I have my laboratory power down; It is a TTI EX4210R, which turns on but does not generate any voltage and current at output (0V, and 0A on LED displays), the fan turns. Does anyone have the schema, or, would someone have an information about this failure? Thank you for your help!

author: Andy Watson
author_rank: Super Contributor
timestamp: February 21, 2017, 07:49:35 pm
content: It might be worth contacting TTI with regard to obtaining the schematic. They have responded positively for some of their older power supplies.

author: wrayman
author_rank: Newbie
timestamp: March 29, 2017, 06:24:53 pm
content: Also have a TTI EX4210R, wondering if you had any luck obtaining a service manual/schematic?I contacted TTI and was informed they don't supply that information..... Maybe I asked the wrong question.

author: Andy Watson
author_rank: Super Contributor
timestamp: March 29, 2017, 07:05:22 pm
content: Try the schematic for the EX1810R linked in this thread:https://www.eevblog.com/forum/repair/ex1810r-repair/msg742813/#msg742813
Thermometer Soar TX-570 shows 10 degrees too low temperature - Page 1
Forum section: electronics / repair

author: AndersJ
author_rank: Frequent Contributor
timestamp: March 24, 2017, 01:25:24 pm
content: Suddenly it started showing about 10 degrees lower than it should.Drifts a bit upon startup then stabilizes.Any ideas any one?Sorry, I cannot figure out how to rotate the image.

author: mimmus78
author_rank: Unknown
timestamp: March 24, 2017, 01:30:22 pm
content: Check inside. There should be an ntc near the k-type connector. They need to know temperature at the k-type connector to guess the temperature on the other side of the junction.

author: AndersJ
author_rank: Frequent Contributor
timestamp: March 24, 2017, 01:41:41 pm
content: The NTC is there, and reacts to heat, so it is alive.Can't say if it has drifted or is otherwise malfunctioning.

author: mimmus78
author_rank: Unknown
timestamp: March 29, 2017, 06:03:04 am
content: Well, if you have a static offset you should check this part of circuit. Basically temperature shown on display is the sum of the temperature of the ntc + the temperature of the k-type probe. If you short the k-type connector with a single piece of wire, you should read the temperature of the ntc on display, this should be similar to temperature ambient (if meter is not manipulated too much).Inviato dal mio Nexus 6P utilizzando Tapatalk

author: AndersJ
author_rank: Frequent Contributor
timestamp: March 29, 2017, 07:07:24 am
content: Shorting the connector does not affect the reading.In ice it shows zero.In boiling water it shows 50 degrees (C).It seems to be span issue, since it shows about half of the expected reading.At room temperature it displays approximately the expected temperature/2,thus my incorrect and sloppy assumption about a 10 degree static offset.A circuit diagram would help, but I have not been able to find one.

author: jeroen79
author_rank: Frequent Contributor
timestamp: March 29, 2017, 07:22:26 am
content: Are there no trimmers to adjust the reading?If the problem started 'suddenly', did anything happen to the meter?Can you do some measurements around the K-type connector?Is it dirty? Does it have a higher contact resistance?Does it cause a drop in the thermocouple's voltage?

author: mimmus78
author_rank: Unknown
timestamp: March 29, 2017, 12:46:10 pm
content: Can you take a photo of the inside PCB?If there are no trimmers and it doesn't use a standard chip it can be hard to proceed with repair.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: March 29, 2017, 12:50:39 pm
content: I didn't asked, you tried to replace this k-type probe.Inviato dal mio Nexus 6P utilizzando Tapatalk
UCurrent Gold - Page 1
Forum section: electronics / repair

author: elmezie
author_rank: Newbie
timestamp: January 16, 2017, 06:02:45 am
content: Hello,Is it possible to fix a blown resistor on the Ucurrent Gold? I can no longer get accurate values on the 1mv/ua setting?I applied too much current while in that switch position and think I blew the resistor?Thanks in advance for any information.

author: tautech
author_rank: Super Contributor
timestamp: January 19, 2017, 05:37:26 pm
content: Quote from: elmezie on January 16, 2017, 06:02:45 amWelcome to the forum.Try this link and links within for the schematic and other info:https://www.eevblog.com/projects/ucurrent/

author: LA7SJA
author_rank: Regular Contributor
timestamp: January 19, 2017, 11:51:04 pm
content: Take your most accurate ohm meter an measure on the ucurrent input in the mv/uA setting, it should read 10 KOhm (R2) (But if r2 has burn due to high current >0.1W in 10K what was the voltage and what else was destroyed). I have two fast lo capacitance diodes back to back over the input to prevent burning out the shunt resistors when I f... up.Johan-Fredrik

author: JDW
author_rank: Frequent Contributor
timestamp: March 29, 2017, 09:02:46 am
content: Quote from: LA7SJA on January 19, 2017, 11:51:04 pmCan you post a schematic of where your diodes are located and also link the datasheet for us?By the way, if the addition of those 2 diodes prevents shunt burn-outs without adversely affecting precision of the uCurrent Gold, why were they not included in the original design? For truly, it is mentioned that the circuit was not "fused" at all in order to obtain the best precision possible.Thanks.
Agilent / Keysight Technologies DSOX2024A doesn't boot - Page 1
Forum section: electronics / repair

author: Neviolograpy
author_rank: Newbie
timestamp: January 24, 2017, 06:51:31 pm
content: I have an Agilent Technologies DSOX2024A oscilloscope bought in October 2012.I use it as hobby so very infrequently. It is as new and has very few hours of work. A few days ago I tried to turn it on and it freezes at boot. No way, it does not start; it stops at the loading screen and remains there, with light on push-button that turn on and off periodically.I read that the problem is well known so... Does Keysight launched a repair services?How can I fix the problem? I had paid 3500 euro from Farnell. An investment for the future, I thought ...By entering the code on the site I get that the warranty has expired (3 years warranty europe).Help!

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 24, 2017, 07:45:44 pm
content: As far as I know the problem is indeed well known and will be fixed under warranty even if your original warranty has expired. Give Keysight a call.

author: Neviolograpy
author_rank: Newbie
timestamp: January 24, 2017, 08:29:22 pm
content: This is a good news, I now contact Keysight TechThank you very much for your help!

author: Neviolograpy
author_rank: Newbie
timestamp: March 29, 2017, 08:59:15 am
content: After some month, I confirm that HP-Agilent repairs oscilloscopes also not under warranty (my warranty had expired by one year and a few days) free of charge if the problem is due to that famous flash data retention. The only expense I paid is shipping (one-way; they have paid the shipping back)So... a positive judgment for Agilent!Greetings from Italy (Trieste)
Canon PC735 Copier Service - Irvine, CA? - Page 1
Forum section: electronics / repair

author: John_ITIC
author_rank: Frequent Contributor
timestamp: March 26, 2017, 10:34:50 pm
content: As the title states; I have a Canon PC735 copier, which has a broken belt. Does anyone know whether there is a repair shop in the Orange County, CA (Irvine) area that can fix the issue? I 10 years ago had the copier serviced in a small shop in Lake Forest, CA but it appears the place is no longer there.Thanks.

author: pishta
author_rank: Contributor
timestamp: March 27, 2017, 02:26:33 am
content: Is the belt a toothed belt? JK electronics in Westminster as well as MarVac in Costa Mesa sell PBR line of rubber belts. I get all my Cassette deck belts there. ~5$ a piece. I know Canon had a camera repair facility in Irvine, I got a recalled Canon MiniDV repaired there.

author: John_ITIC
author_rank: Frequent Contributor
timestamp: March 29, 2017, 02:15:52 am
content: Quote from: pishta on March 27, 2017, 02:26:33 amI have no idea where it came from and I don't have the time myself to become expert in this copier. I was hoping to find an old-timer shop where I can drop the thing off. I checked the Canon web site but nothing useful. Also, any commercial "copier repair" companies are only servicing large corporate copiers. I can't blame them since hardly any profit in fixing these old things...I'll bump this thread from time to time...
Braun 3709 electric toothbrush noise - Page 1
Forum section: electronics / repair

author: m.m.m
author_rank: Regular Contributor
timestamp: March 25, 2017, 09:10:58 am
content: Hi,I've installed a new battery on my 3709 Braun toothbrush, but I couldn't install the packaging properly and some water leaked into the electrics,and now even that it's dried completely it makes a noise when it's turned off, some sort of ticking, just like a slightly high voltage discharge, and it repeats about 15 times a second.This is what the scope shows at motor terminals at different time domains:what do you think?

author: samnmax
author_rank: Regular Contributor
timestamp: March 27, 2017, 12:25:19 pm
content: I have a similar model and it also makes a ticking sound. Here it says it's normal (search for "ticking"):http://www.service.braun.com/product/search.asp?rg=NA&c=US&l=GB&typ=faq&frmTyp=grp&sgrp=grp&grp=21&s=Quote
Tek Scope Probe Repair - Page 1
Forum section: electronics / repair

author: Rerouter
author_rank: Super Contributor
timestamp: March 27, 2017, 11:13:22 am
content: First and foremost, I'm mainly doing this as a learning exercise, i already have enough working probes to handle my day to dayOne of my older fixed X10 probes has a partial breakage at just past the stress relief, about half the sheilding is still intact, and the probe itself still functionsI am wondering if there is any better way to fix it that putting 4:1 heatshrink over the probe and down the wire?e.g. is there any kind of inline splice crimp for this kind of thing, or a way to reverse out the original crimp and loose 2 inches

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 27, 2017, 11:27:44 am
content: The cable is probably part of the divider network so cutting off a piece is likely not a good idea. What I would try is peeling a bit of the plastic from both ends of the break, get some shielding from another cable to put over the gap, then heat shrink and be done.

author: Rerouter
author_rank: Super Contributor
timestamp: March 28, 2017, 10:06:43 am
content: Thanks for the advise, it actually makes a very sturdy repair.I trimmed 5mm back on either end, then tightly wound copper braid around it and i am just waiting on more stock of 12mm 4:1 heatshrink to seal it over, but so far it maintains most of its original flex, which considering it failed right next to the stress relief is needed,