hybridfree/eevblog-posts huggingface dataset:
Micro-USB & Audio Connector - BOSE Soundlink - can anyone identify - Page 1
Forum section: electronics / repair

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: September 29, 2018, 02:19:59 am
content: I have a BOSE Soundlink Colour audioplayer with a dodgy micro-USB connector. It won't charge reliably and I've pinned it down to a bad connector - reflowing the solder joints didn't help. Attached photos show the module, which has a regular audio out jack and micro-USB charging input. Both are potted into the connector so not so easy to replace the USB. Only identifying feature is code L1427 on one side. Web search didn 't turn up anything yet. Wondering if anyone has seen such a thing as a non-proprietary item and, if so, where I might get one? Thanks.

author: Rerouter
author_rank: Super Contributor
timestamp: September 29, 2018, 02:23:00 am
content: Would you be able to determine the pinout? You may be able to just bodge one up.

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: September 29, 2018, 08:25:09 am
content: One option is to take the Dremel to the micro-USB and then pot in a replacement. 2nd option would be to bodge in a couple of leads/plugs. Haven't looked into the internal circuit yet but I don't think there's a lot of complexity happening around these connectors. Thought I'd try for a direct replacement of the whole thing first up. Long shot but...

author: coromonadalix
author_rank: Super Contributor
timestamp: September 29, 2018, 04:59:58 pm
content: maybe ordering the part at bose

author: wraper
author_rank: Unknown
timestamp: September 29, 2018, 05:36:14 pm
content: This assembly is proprietary thing, connector inside it should be off the shelf part, though.

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: September 30, 2018, 12:42:05 am
content: Thanks all for the useful feedback - I suspected it was likely a proprietary part. I'll try Bose as suggested but I find many suppliers these days are not helpful on spare parts and at best will offer whole replacement board or repair in-house - not worth it in this case. I'll source a suitable connector and see how I go potting it in.
HP8590L replace orgiginal YIG with a slightly different type and make it work - Page 1
Forum section: electronics / repair

author: Bjoern
author_rank: Contributor
timestamp: September 29, 2018, 03:29:03 am
content: The original YIG (2.0 - 4.0 Ghz) doesn't deliver enough output. I sourced for an alternative YIG that should be a close match (5086-7259 YIG Oscillator: 2.0-4.5 GHz, 15-18 dBm). When I attach my simple RF amp. meter it shows +5db which is still 10db lower then I hoped for but I continued to make the connections.I used external power supplies as the voltages differ from the original one (+20v, -10v). My first question would be if it is save to use the analyzers power rail from -5v to +15v to come up with the required +20v without the risk of running into some ground loops?The required current to control the frequency is different from the original one, I placed a resistor in parallel to the main coil to shift the frequency downwards and it seems to work. I see on the analyzer screen (using int. ref. signal of 300Mhz, -20db) a -29db signal which is out of frequency. I can shift the peak to the right place (e.g.300Mhz) but when I change the centre frequency of the analyzer it is out again and requires again manual interference on the parallel resistor.I see no difference when I connect or disconnect the FM coil (and I am not sure if I choose the right connection), can somebody elaborate how I could best test the function of FM coil ?Another problem is, when I cross from SPAN 10Mhz to below 10Mhz, below I see only a flat line :-(So in summery I conclude that the YIG is oscillating, the frequency is not always in the right place and the PLL seems to be unable to control it. The output level seems 10db too low (not sure if that is a big problem as the calibration might be able to compensate for that ?). The FM coil doesn't work yetAny suggestion from somebody who did conversion work in that manner id highly appreciated !!

author: collett.marcelo@gmail.com
author_rank: Newbie
timestamp: September 30, 2018, 05:42:56 pm
content: hello,I am trying a similar work on my HP 8592B, replacing the YIG for a alternative model.I also could not make it work perfectly yet because in SPANS below 10 MHz the center frequency is very unstable....Regarding your doubts, I discovered the FM coil is used just below the 10Mhz SPANS and this explain why you have no signal from zero to 10 Mhz SPAN.... probably your YIG has no output in the SPAM below 10 Mhz because you did not connected this coil .Let me know your progress !BR,Marcelo
Keithley 2700 weird jump in measurement values - Page 1
Forum section: electronics / repair

author: petemate
author_rank: Regular Contributor
timestamp: September 27, 2018, 09:40:23 pm
content: Hi,As some of you may know, I have successfully repaired a Keithley 2000 DMM. I also had a broken 2700, which I have now also "repaired"(That was a simple question of replacing some of those JFET switches). I thought I wanted to test the two against each other, so I produced these measurements(please note that the 2700 is plotted on the right Y axis):As one can see, the 2000 works fine(I expected this drift due to warm-up time), but the 2700 is making some weird jumps here.Here is a zoomed-in plot of some of the jumps:The Keithley 2700 jumps about 170uV a single reading, then going back to the "base level" again. These jumps becomes more frequent, until it finally settles on the new level. This looks almost like some ADC LSB-shift behavior. But that can't be, since it has much more resolution than this and is able to distinguish the fine changes in the "base level" just fine. Does anybody have an idea about what could cause this behavior?To repair the 2000, I temporarily took parts from the 2700(e.g. the TF-245 resistor array). But I made sure to put those back. And even though it would void the calibration, I don't see why it should cause these jumps..Any ideas?Thank you for your time.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 28, 2018, 09:59:06 am
content: The jumps are rather large. 170 µV corresponds to 17 ppm of 10 V nominal FS or some 12 ppm of of the 14 V reference. So this would be something like 2 µs of the full reference active at 200 ms integration time. This a little to much to attribute this to the slow slope part (that was broken on the K2000). So it could be something like 1 bit (not the LSB, but more like somewhere in the middle) of the result not properly transferred (e.g. aged opto-coupler).I very much doubt it, but it could also be a problem with the reference or an related OP. So does a similar effect also happen in resistance mode ?Another point to check could be a signal slowly changing over a larger range (e.g. a few mV in 10 V range, or a few ohms in 10 K range - something like a PTC slowly heating or cooling), to see of the odd jump pattern repeats.A first point to check would be the supply for the ADC part, especially the 5 V for the CPLD / gate driving logic. Also check the reference voltages, in case there is a bad solder junction / short around the TF245.

author: petemate
author_rank: Regular Contributor
timestamp: September 28, 2018, 05:54:34 pm
content: Hi Kleinstein,I just had another go at it. I got to ~650 readings, then the 2700 locked up and showed the exact same symptoms as the 2000 did back before it was repaired.. Initial sampling, but "lock-up" after some time. I am fearing that I have the same problem with the 2700 as with the 2000. But we will see. Anyway, there is no reason to pursue the 2700 offset/jump issue until I get the unit fixed. I'll post again if I need repair assistanceThanks for your time!
Yamaha RX-V677 HDMI output drops video signal when you physically tap on it - Page 1
Forum section: electronics / repair

author: dannykay
author_rank: Newbie
timestamp: September 28, 2018, 07:28:14 am
content: Hello,My yamaha receiver drops HDMI video output for 1 or 2 seconds when you physically tap on the receiver, move it, jump near it, or there is some movie bass (probably because the cabinet its in vibrates). It's worth noting that this does not happen when the unit is cold (just turned on) but starts after it has been running for a little bit (the more time its been running the more sensitive to the tap it becomes). The unit is very cool to the touch and has a PC fan running on top of it.I have no yamaha service center where I live now and looking for some pointers that can help a buddy who repairs electronics.One thing to mention is that I believe this whole problem is due to the unit running for 2 years in a poorly ventilated location causing it to probably run hot at the time.thanks for any help.

author: mzacharias
author_rank: Frequent Contributor
timestamp: September 28, 2018, 09:54:38 am
content: Bad connections at the HDMI jack itself - or poor solder connections where it attaches to the board itself. In addition to possible heat issues, the weight ofthe cables themselves can contribute to this, especially if using "high-end" cables.Most HDMI jacks are surface-mount soldered anymore. A very steady hand might be able to re-flow the solder. In my experience trying to add more solderto connections this close together is asking for trouble.

author: Silveruser
author_rank: Regular Contributor
timestamp: September 28, 2018, 05:30:18 pm
content: Always suspect the cable. I went thru a similar problem with my TV, kept changing positions. Finally replaced the cable no trouble since. Tiny wires don't last forever in a stress situation.
Agilent 2k series LED partially light up with no display - Page 1
Forum section: electronics / repair

author: rizal5478
author_rank: Contributor
timestamp: September 26, 2018, 02:37:54 pm
content: Hello Folks, My Agilent 2k didn't boot-up properly (no display and LED partially light up then hang). From my previous understanding it seem cause by NAND IC. Anyone experience before and able to solve?

author: HighVoltage
author_rank: Super Contributor
timestamp: September 27, 2018, 11:13:36 am
content: I just had a NAND experience for the first time on my DSO-X-3024A and it showed all LED correctly and the screen also turned ON correctly and bright. Just the bootup did not finish and stayed in boot loop.So, I think in your case it is a different problem, but I am not 100% sure.

author: Samogon
author_rank: Frequent Contributor
timestamp: September 27, 2018, 01:41:59 pm
content: TheSteve fixed many scopes with this issue.

author: rizal5478
author_rank: Contributor
timestamp: September 27, 2018, 02:31:12 pm
content: Ya, seem it different with my case. For your case, did you re-program the NAND IC?

author: rizal5478
author_rank: Contributor
timestamp: September 27, 2018, 02:35:00 pm
content: Hope TheSteve will provide step to diagnose in identifing the actual failure

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 27, 2018, 02:39:18 pm
content: I told you how to proceed in a reply to the PM you sent me:Quote

author: rizal5478
author_rank: Contributor
timestamp: September 27, 2018, 02:49:51 pm
content: Quote from: PA0PBZ on September 27, 2018, 02:39:18 pmYes, PAOPBZ, thanks again.. I saw picture from the thread to tap with serial-USB on the board but I don't have idea how to communicate with the PC. Seem not explain in the thread.

author: TheSteve
author_rank: Unknown
timestamp: September 27, 2018, 05:05:18 pm
content: Quote from: rizal5478 on September 27, 2018, 02:35:00 pmI also said in PM you need to connect to the internal serial port for us to help you.

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 27, 2018, 06:29:35 pm
content: Quote from: rizal5478 on September 27, 2018, 02:49:51 pmIt was not explained in the thread because it is considered basic knowledge, you need one of those USB to serial TTL converters and a terminal program, most of us use PuTTY.Please do some googling and reading, we can help you but not from starting point zero.

author: rizal5478
author_rank: Contributor
timestamp: September 28, 2018, 02:41:48 am
content: Quote from: PA0PBZ on September 27, 2018, 06:29:35 pmok noted and thanks.. i did use hyperterminal for other device before just doubt if u guys using any special GUI. Just heard abg putty and i will explore further. I had ordered USB-TTL 3V converter for this and will let you guys know the outcome later.
HP8901B Modulation Analyzer Repair Part 1 - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: September 28, 2018, 02:21:22 am
content: Hi All,I just thought I would post this here, although it's a pretty simple repair it still has some interesting aspects for diagnosis.Part 2 (where I finish the repair) will be published next Friday.
Metrel OmegaPAT MI 2140 repair help - Page 1
Forum section: electronics / repair

author: Finklestein
author_rank: Newbie
timestamp: September 28, 2018, 01:29:24 am
content: Hi,I'm looking for a schematic for the Metrel MI 2140 or maybe someone has one & can provide information about the  ceramic capacitor which seems to have "gone nuclear"... all I have is that it was blue & the number 14.Any help would be greatly appreciated
YIHUA 938BD+ Is the mainboard OK? - Page 1
Forum section: electronics / repair

author: TBS
author_rank: Contributor
timestamp: August 25, 2018, 08:00:11 pm
content: Hello everyone,not sure if this is the right subforum or "Other Equipment & Products" would be better – feel free to move it.A couple days ago, I’ve got an "YIHUA 938BD+" soldering station (picture below). The package came a without any duct tape and practically accessible to anybody. I check the accessories and just to be sure opened even the machine, since there was no sealing sticker present.There is a mainboard marked "YH-NZLT2-V1.0" (picture below). Beside the terrible job of soldering and other things, I found a resistor place R18 to bebridged with solder(without any resistor) (marked on picture) andscratches on the boardthat obviously cuts a couple of lines on the board (marked on picture). These things made me worried and stopped me from powering it up.I need help from someone who have this "YIHUA 938BD+" soldering station and canconfirm to me that those things are okand should be there. Otherwise I will return this station back to the seller immediately. Unfortunately, I didn’t find any service manual on the internet.Thanks anyone for help

author: PKTKS
author_rank: Super Contributor
timestamp: August 27, 2018, 12:33:02 pm
content: 2 cents.. I have seen some youtubers posting reviews of this tweezerssome older versions and stuff...Some of them can not even tolerate the heat and break apart upon usingFirst time i am seeing a 100% crappy board like this.Considering the operational current and heat of the tool....That thing deserves to be delivered back to originNot suitable for use. Don't even bother wasting time on it.100% garbage.I would take it apart and try to use what is possible as dummy parts....just to avoid ditching toilette flush ragedPaul

author: abraxa
author_rank: Frequent Contributor
timestamp: August 27, 2018, 03:37:01 pm
content: Looks like factory rework to me, I wouldn't find it concerning personally. Not done professionally, sure, but this *is* a budget unit.

author: Rasz
author_rank: Super Contributor
timestamp: August 27, 2018, 09:23:10 pm
content: $100 chabuduo

author: TBS
author_rank: Contributor
timestamp: September 27, 2018, 07:37:27 pm
content: So, to close this topic - I put the thing together again and yes, it WORKS.Sure, the soldering inside is wacky - its all by hand and the board is scratched here and there. I tested the memory buttons and heating and everything seems to be OK.So, the answer for anyone who would seek the same answer is: The board should look bad, scratched and bridged with solder, it will work just fine.Thanks everyone for suggestions.
TV turns on, lights up but blank screen & no audio - Page 1
Forum section: electronics / repair

author: AndyMacSteve
author_rank: Newbie
timestamp: September 22, 2018, 12:03:20 am
content: I picked up my old TV from my basement which I havent used for a year, powered it on, the screen lights up but it is blank with no audio or video output.The model is a Panasonic TC-L47E50 LCD.I haven't done too much testing or diagnosis, because I think the problem is not the internal power supply but potentially a problem on the T-CON board or the secondary board(s).One of the caps measured 300V 10 minutes after unplugging and showed no signs of discharging and some diodes seemed to be shorted (diodes normally allow 1 way power flow only, but this ones seems broke)Could it be a power supply problem, or a much more complicated T-CON board or other board problems?

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 22, 2018, 01:00:54 am
content: Can you access the menus?

author: Seekonk
author_rank: Super Contributor
timestamp: September 22, 2018, 03:17:02 am
content: I had that same problem a couple weeks ago. It was called lightning, hit 30 feet and blew a hole in the ground. My solution was a DTV converter box fed into AUX. I just wish it hadn't taken out the amplified antenna.

author: james_s
author_rank: Super Contributor
timestamp: September 27, 2018, 12:55:00 am
content: Did it work last time you used it? Do any of the controls do anything? Does it get moist in the basement where it was stored? How are you testing the diodes? Beware that testing parts in-circuit can give misleading results. I would start by checking the outputs of the power supply, often they are printed right on the board.

author: AndyMacSteve
author_rank: Newbie
timestamp: September 27, 2018, 01:06:41 pm
content: Im just putting the probes across the two diode terminals, and they give the same resistance in both ways.And no the controls are doing nothing. Not even the menus.And I also dont remember any lightning or weather causing problems on my TV

author: james_s
author_rank: Super Contributor
timestamp: September 27, 2018, 03:46:09 pm
content: A resistance check won't tell you anything, in many cases a modern meter will not pass enough voltage to bias the diode. Does your meter have a diode test function? Most do. It's unlikely the diodes are bad though, if they were shorted the tv would probably shut off, blow the fuse or smoke.
Replacing faulty thermistors - Page 1
Forum section: electronics / repair

author: XaviPacheco
author_rank: Regular Contributor
timestamp: September 27, 2018, 02:19:10 am
content: I have a three phase motor controller which has two thermistors SL22 1R020, located at the positive and negative leg of a bridge rectifier respectively. Then, it feeds a bank of capacitors. I can try uploading an schematic if needed for this. One of the thermistors is burnt. I don't have the same replacement. However, I have this one SL32 2R025. Do you think it works? I haven't made a deep analysis on why the designer selected that thermistor value.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 27, 2018, 09:46:52 am
content: the first : SL22 1R020 is 1 ohms at 20 ampsthe second : SL32 2R025 is 2 ohms at 25 ampsIf the thermistor has blown, it must have or had a reason ? Sure you can do an substitution with the second part number.But maybe the motor may have begun to show problems symptomsDo they need some maintenance ?? bearing check, rotor check, lubrification check, dust clean up ??We had failed bearings in one of our at my job, it began to trigger current protection ??
Fluke 87 V high voltage repair - Page 1
Forum section: electronics / repair

author: curtgibson
author_rank: Newbie
timestamp: September 25, 2018, 03:53:42 pm
content: I hope replacing the parts will repair my fairly new 87V. Can anyone help me identify the part numbers, or type of part and values, and maybe a source for the parts?

author: curtgibson
author_rank: Newbie
timestamp: September 25, 2018, 11:37:47 pm
content: From other posts, I believe this is a :‎Digikey part# 235-1493-ND‎‎YS4020‎PTC RESET FUSE 1.0KV RADIALThe Fuse was also found as an Ohmite‎OY102KE-ND‎‎OY102KE‎RES 1K OHM 2W 10% AXIAL

author: retiredcaps
author_rank: Super Contributor
timestamp: September 26, 2018, 06:40:20 am
content: Quote from: curtgibson on September 25, 2018, 03:53:42 pmBefore replacing anything, what is exactly wrong with your meter? Please post clear focused pictures of your pcb so we can see what yours looks like.If your 87V is "fairly new" and you are the original owner and bought this from an authorized dealer, have you contact Fluke directly for potential free warranty service?

author: bd139
author_rank: Super Contributor
timestamp: September 26, 2018, 07:21:54 am
content: If it's protection that has blown up, short out the PTCs and fuses with clip leads, make sure all spark gaps are clear and test it on low current limited voltage first. Make sure the meter at least roughly works before you bother repairing it and that there is no physical carbonised traces or bits of board. If any of that is bad then discard it - it won't take that a second time so you'll be putting yourself at risk. If it looks ok, make sure when you've done it you clean the board afterwards with isopropyl alcohol to stop any creepage paths appearing.But agree, check warranty first!

author: curtgibson
author_rank: Newbie
timestamp: September 26, 2018, 10:58:23 pm
content: I installed 1K resistors temporarily to replace the thyristor and fusible resistor. Then I tested resistance for a 100 Ohm resistor, but it read 45 Ohms. So it is not working at that point.So the parts that I purchased do not seem correct, since they have 1K resistance for each. Or the meter is damaged deeper than the protection circuits.

author: floobydust
author_rank: Super Contributor
timestamp: September 27, 2018, 09:08:07 pm
content: With nothing connected to the DMM, put it in ohms and then diode test and it should read OL.If it doesn't, then there are still shorted protection components.After the PTC, MOV, HV resistor, there are some transistor clamps that can get taken out, if you lent your multimeter to Nikola Tesla.The current-shunt clamp diodes/bridge fail if it was grossly overloaded measuring current with the wrong fuse installed.
Help with my P4 motherboard - Page 1
Forum section: electronics / repair

author: alah
author_rank: Contributor
timestamp: September 24, 2018, 06:46:57 pm
content: Hi ALL; my P5P800-VM mother board doesn’t even run BIOS.Should it? even if the processor is bad or missing?

author: David Hess
author_rank: Super Contributor
timestamp: September 24, 2018, 10:53:05 pm
content: No, the BIOS will not start if the processor is bad or missing.

author: Nerull
author_rank: Frequent Contributor
timestamp: September 25, 2018, 04:10:52 am
content: The BIOS is just a rom full of code and data, that code has to execute on something. You need a processor.

author: alah
author_rank: Contributor
timestamp: September 25, 2018, 05:11:04 pm
content: Thanks, I¨ll change it.

author: Rasz
author_rank: Super Contributor
timestamp: September 25, 2018, 08:46:12 pm
content: this is the bad capacitors vintage, I would start there ()and power supply)
Damage power supply board  - Page 1
Forum section: electronics / repair

author: Mixergr
author_rank: Newbie
timestamp: September 25, 2018, 08:57:35 am
content: Dear All, I need your help to identify the exposed part of the power supply board.Item damage is the D501.TV3206-ZC02-01(A) KB-5150 Universal Power Supply Board E59670 P/N 303C3206063 is the power supply board.Is from Grundig tv G32LCD.Thanks.

author: bob225
author_rank: Frequent Contributor
timestamp: September 25, 2018, 10:38:18 am
content: you picture is a bit small, but from other pics on goggle there are a pair of resistors and a mov by the looks of it D prefix makes it a diodeWhat is the issue with the board ? these a well known for bad caps

author: Mixergr
author_rank: Newbie
timestamp: September 25, 2018, 01:33:17 pm
content: the tv receives the orders to open and close (can see the led red-blue) but no sound and no picture. That part D501 blow up the front part gone and we cant to know the specification on it. All the other parts, capacitor, resistance, diode, transistors remove most of them checked and is ok. looks only this part damage .....

author: rmacintosh
author_rank: Regular Contributor
timestamp: September 25, 2018, 02:14:12 pm
content: Shop Jimmy sells a repair kit for this power supply board.It doesn't indicate what parts are included in the kit but there appears to be a TO-220 diode included.Is that the only TO-220 diode on this board?If so, that would be the blown diode on your power supply.Otherwise shooting them an email to get the parts list for this kit will get you the part number, and outright ask if the included diode is the D501 replacement.https://www.shopjimmy.com/catalogsearch/result/index/?q=PS1103159AC+Repair+Kit

author: bob225
author_rank: Frequent Contributor
timestamp: September 25, 2018, 02:16:15 pm
content: is it just the 24v line that's gone down ?

author: bob225
author_rank: Frequent Contributor
timestamp: September 25, 2018, 02:27:06 pm
content: A bit more diggingDual diode rectifier MBR20200CT ( alternative part SBR20200 or SF20LC30 )Edit. just come across the schematichttps://www.electronica-pt.com/esquema/lcd/tv3206-zc02-01-100w-lcd-tv-power-supply-sch-67482/
Samsung LED Monitor Flicker/Interlaced Problem Repair - Page 1
Forum section: electronics / repair

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 24, 2018, 10:45:08 am
content: i bought Samsung S27E310 LED Monitor just few months ago (recent 1-2 years ago) and now it starts to show some defect. 1stly its not so serious, just brighter portion of screen at the 10% of the bottom part, but now it gets worst with about 40% of the bottom part is flickering/whitish/interlacing effect. you can see the effect in the attached pictures and videos. is this a simple capacitor damage replacement fix? or something else more serious? i'm going to open up my monitor i will unable to forum from my PC, so i will probably be viewing your repair advice from my handphone. Samsung is going to get a big thumb down from me. waiting your reply thanks.youtube=P5H4r9lG82Myoutube=_8aVD4TGhj0

author: Rasz
author_rank: Super Contributor
timestamp: September 24, 2018, 05:53:31 pm
content: Did it go away when whacking monitor on the side?This looks like glass-flex bond/chiponflex issue, usually not fixable unless you are a Russian level of hackery wizard.
GW Instek GOS-620 schematic needed - Page 1
Forum section: electronics / repair

author: Sylvi
author_rank: Regular Contributor
timestamp: September 23, 2018, 11:37:56 pm
content: HiI have a GW Instek GOS-620 20MHz analogue oscilloscope that is six months out of warranty and I would like to get the schematic for it. Does anyone have one or know where to find one?Instek has discontinued this unit from what I understand, replacing it with its bigger brother which has a built in multimeter and component tester or other stuff.My scope has a problem in the vertical positioning for both channels. If there is a small sine wave (2-divisions peak-to-peak) in the lower half of the display and I sweep it upward using the vertical position control, the wave gets smaller until it is a flat line about three-quarters of the way up. If the sine wave is a bit larger, it will be okay at the bottom of the screen but as it is swept upward the top half distorts then clips.I suspect the problem will come down to a bad solder connection in the vertical offset circuit.I ordered a new DSO which might be here in a week or two, after which I can open up the Instek and work on it with impunity.

author: tautech
author_rank: Super Contributor
timestamp: September 24, 2018, 02:54:29 am
content: http://www.produktinfo.conrad.com/datenblaetter/125000-149999/129640-sp-02-en-30_MHz_Oszilloskop_630.pdf

author: Sylvi
author_rank: Regular Contributor
timestamp: September 24, 2018, 04:02:36 pm
content: THANK YOU !!!!
DS1102D Rigol Oscilloscope Rotary Encoder Problems - Page 1
Forum section: electronics / repair

author: Omar Mekkawy
author_rank: Contributor
timestamp: July 08, 2018, 12:23:33 am
content: Hi Friends,I got a DS1102D Rigol Oscilloscope and I don't know what is going on with its rotary encoder. ( Its LJV Brand )it looks like my problem like this problems in this video :It happened once more than one year ago and I have opened the oscilloscope and disassembled the rotary encoder and cleaned it and it worked fine. This also happened again now and I have a little dusty lab. Is this due to dust ? or what ?Also I have upgraded the firmware to the latest version from two years a go. could this the cause of the problem ?if there any replacement for this rotary encoder, does anyone tried them for a long time ?Thank You for your help.

author: cs.dk
author_rank: Unknown
timestamp: July 08, 2018, 06:44:13 am
content: I don't know for sure it'll work, but there is a forum post here about encoders in the DS1000Z series scopes;https://www.eevblog.com/forum/testgear/rigol-ds1054z-rotary-encoder-mod/

author: Omar Mekkawy
author_rank: Contributor
timestamp: September 24, 2018, 06:12:27 am
content: I sent an Email to the Technical support of Rigol and told them the problem and if they can send me a replacement for the user interface board because I can't afford sending the oscilloscope back for servicing, they took the serial number and checked my problem as solved without even helping me solving it!!!

author: LapTop006
author_rank: Unknown
timestamp: September 24, 2018, 06:50:46 am
content: This happened to mine when I went to use it recently after a long period (years). In my case it's time for a new scope anyway (hopefully finally being delivered this week).Being unreliable like that is almost more annoying than being completely broken.

author: Omar Mekkawy
author_rank: Contributor
timestamp: September 24, 2018, 01:07:37 pm
content: Yes, if I knew that problem earlier I will not even try Rigol again. Their servicing and technical support sucks.

author: Omar Mekkawy
author_rank: Contributor
timestamp: September 24, 2018, 01:08:36 pm
content: Quote from: LapTop006 on September 24, 2018, 06:50:46 amWhat is the model number of scope you bought ?

author: LapTop006
author_rank: Unknown
timestamp: September 24, 2018, 01:39:02 pm
content: I wanted something with a big (for a scope) screen, and combined with a few other things ended up buying a (refurb) Keysight 6000-X.Not anywhere near the same price class as the Rigol. We also just picked up a 1074Z for the office lab, so I'll get to see how nice they are soon.
Some people shouldn't own variacs - Page 1
Forum section: electronics / repair

author: GregDunn
author_rank: Frequent Contributor
timestamp: September 27, 2018, 12:26:45 am
content: OK, not really repair, more like "made safe again". When I picked up my HP6920B at the hamfest this weekend, I was walking past a table from an estate sale and this huge variac called out to me. I only have a very cheap, low current unit in the lab, and frankly I was afraid it was going to blow its fuse sooner or later - or worse. This thing was beefy enough to handle anything I was likely to throw at it. The people handling the sale said they had powered it up and it worked, but had no idea what a variac should cost, so I Googled variacs and showed them "see - anywhere from $20 to $1000, depending on who made it or how much power." They said "OK, $20." Sold!I knew it was going to take a little cleanup - the first thing (you can see) is that the previous owner decided it needed a handle, so he bent up a piece of aluminum pipe and screwed it to the case. Yes, through the case, who-knows-how-close to the windings.The next thing (take my word for it) is that he apparently used it with equipment having grounded plugs, so to make them fit he drilled a hole under the plug.I disassembled it and undid all the safety hazards. It's not badly made and even has a cheap voltmeter to indicate the voltage. Weighs about 20 pounds at least.I'm just hoping that this wasn't an estate sale for someone who electrocuted himself...

author: sokoloff
author_rank: Super Contributor
timestamp: September 27, 2018, 12:29:24 am
content: Quote from: GregDunn on September 27, 2018, 12:26:45 amThat's a particularly odd combination of lazy and industrious... (Isn't an extension cord or a cheater plug easier than getting the drill out and having a go at it?)

author: coppercone2
author_rank: Super Contributor
timestamp: September 27, 2018, 12:55:45 am
content: this is because ham shacks deter women which allows for beer use during complex tasks

author: GregDunn
author_rank: Frequent Contributor
timestamp: September 27, 2018, 02:19:42 am
content: Quote from: sokoloff on September 27, 2018, 12:29:24 amI have been known to use a cheater plug when working with audio gear, as long as I know where the ground is and how my test equipment is connected. This guy probably had some high power RF gear in his shack, and that's not to be fooled around with lightly... I hope that at least he looked inside before applying the drill; the ground pin would have been in close proximity to the hot input lead, and the little grommet holding the power cord was already loose and easy to rotate in its slot.
Service Manual / Schematics for Rohde & Schwarz AFG (377.2100.02)? - Page 1
Forum section: electronics / repair

author: rachaelp
author_rank: Unknown
timestamp: March 09, 2017, 06:46:58 pm
content: Hello,I picked up a Rohde and Schwarz AFG from eBay a week or so back which I got cheap as it needs a repair. Before I pull it apart to try and work out what might be wrong I was wondering if anybody could help with schematics or a service manual for this unit? I've done a lot of Googling but haven't come up with anything yet, I know it's a really old unit but hopefully they are available from somewhere still?Many thanks,Rachael

author: Marflow5
author_rank: Newbie
timestamp: September 23, 2018, 10:25:01 am
content: Hi Rachael,I am just reading your post hoping that you can help me because I also got a Rohde and Schwarz AFG which needs repair and I have no service manual fpor it. In case you have found a manual in between and you would like to shar it with me I would really be happy.Many thanks,Marflow

author: rachaelp
author_rank: Unknown
timestamp: September 24, 2018, 09:18:03 am
content: Hi Marflow,Unfortunately I wasn't able to find a service manual for this. I contacted lots of people trying to locate this and even those who sell a vast array of R&S service manuals weren't able to help, one even saying he'd buy it from me if I were able to locate one. As a result this unit has sat on my shelf unused as I haven't had the time to try and reverse engineer it just from the boards themselves in order to repair it and is likely to just go back on eBay at some pointGood luck with your unit, I hope you manage to get it repaired. If you do happen to find the manual anywhere please let me know!Best Regards,Rachael
Request assistance with Tektronix 2465A repair - Page 1
Forum section: electronics / repair

author: spint3
author_rank: Newbie
timestamp: September 23, 2018, 03:22:03 pm
content: Hello, new member here, I was wondering if I could get some assistance in repairing my Tektronix 2465A scope. I'm afraid this is a bit out of my knowledge base.I was using the scope one night, and after about 30 minutes of runtime I heard some crackling and saw all the magic smoke escape. Opening it up I found some crusty caps in the power supply and a burnt resistor. I'm in the process of ordering the visually damaged and suspect components, but is there any other service type work I should also do? I've seen a post or two about shotgun re-capping the whole thing, I wasn't sure if that was really necessary. Any recommendations would be greatly appreciated, this is my first time working on test equipment.

author: andy2000
author_rank: Frequent Contributor
timestamp: September 23, 2018, 03:50:17 pm
content: Those line bypass caps are notorious for shorting and smoking. Replace ALL of that type now to avoid problems. Be sure to use the correct X/Y safety rated parts as originally used.You should check the eletrolytics for leaks, and ESR. I did a total recap on mine, but it had many leaking caps. They used different brands over the years, and some were better than others.

author: tggzzz
author_rank: Super Contributor
timestamp: September 23, 2018, 03:54:15 pm
content: Ah yes, the Rifa delayed action smoke generators. These are mentioned many times on this forum; use the search facility!There's a good file from condoraudio.com

author: med6753
author_rank: Super Contributor
timestamp: September 23, 2018, 04:30:13 pm
content: Since you have the Inverter/Regulator boards out now go ahead and do a total re-cap. You can find all kinds of info plus the list of required capacitors here:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/

author: spint3
author_rank: Newbie
timestamp: September 23, 2018, 04:38:28 pm
content: ^wow, that's a whole lot to digest, thanks a ton!
Fit Hakko (or other) Nozzles to Pace Thermoflow TF-200? - Page 1
Forum section: electronics / repair

author: mikkkejickles
author_rank: Contributor
timestamp: September 19, 2018, 04:33:46 pm
content: Hey Folks,Do non-Pace Nozzles (like Hakko) fit on a Pace Thermoflow (or if there is an adapter)?https://www.eevblog.com/forum/buysellwanted/fs-pace-tf-200-thermoflow-rework-system/This is an old unit from 2000.Thanks- MJ

author: mikkkejickles
author_rank: Contributor
timestamp: September 22, 2018, 07:07:55 am
content: Bump!

author: Shock
author_rank: Super Contributor
timestamp: September 22, 2018, 12:49:01 pm
content: Looking at the images (i.e. in google images searching for "hakko hot air") I would say no, not directly.Is it possible that there is an adapter or you could make one? Entirely.If you head to their website and look in product manuals you can probably find the dimensions you need.

author: mikkkejickles
author_rank: Contributor
timestamp: September 22, 2018, 10:14:10 pm
content: Thanks for replying Shock, appreciate it.After a lot of google image searching.....The Hakko (or Hakko compatible) nozzles have aninternal shaft diameter of 22mmNow I just need to measure the shaft diameter of my TF-200 handpiece!One last question - say I *did* create a makeshift adapter (to adjust the Pace Handpiece to work with Hakko nozzles), would it really make a difference do you think to how the device operates?For instance, when its blowing Hot Air into a shaft of say 24mm and then i have an adapter which slims it to 22mm, do you think there is a risk that I'd break the blower unit because i'm reducing the airflow (over time).It's just something I was thinking about, I know these Pace devices can be kind of precise. I just picked this one up at a yard sale, but the nozzles are like... $150, so just trying to use it somehow.Quote from: Shock on September 22, 2018, 12:49:01 pm

author: mikkkejickles
author_rank: Contributor
timestamp: September 22, 2018, 11:35:09 pm
content: FYI - I can confirm - the Pace TF-200 Handpiece Shaft has a diameter of 21.97mm (Tested with digital calipers)Nozzles such as the Aouyue1128ought to fit perfectly.Quote from: mikkkejickles on September 22, 2018, 10:14:10 pm

author: Shock
author_rank: Super Contributor
timestamp: September 23, 2018, 12:57:17 am
content: I would think a similar sized nozzle barrel length and tip width is going to produce similar results. As for any damage or performance differences no idea. I'd follow any guidelines in the manual as well as measure the temp of the output air.
LeCroy LW420 I/O PCB - Page 1
Forum section: electronics / repair

author: Halide
author_rank: Contributor
timestamp: September 22, 2018, 10:17:57 pm
content: HiI have the LeCroy LW420 generator, but without the I/O board. I found a information that this generator don't turn on without it. That's is true? I think it's may hard to buy it, maybe some of you have that one?
LQFP48 - 48-pin, 7 x 7 mm trace repair - Page 1
Forum section: electronics / repair

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 22, 2018, 09:44:00 am
content: On a DSO138 9V pocket scope, I made a real mess trying to solder on/off the MCU. Not a good way to learn how to solder this stuff. I have the latest chip on there, pretty much lined up and soldered down with a lot better technique this time.So now it has about 8-9 broken traces. So there are 1-3mm gaps I need to bridge. 2 I just added a few cm of wire back to the via's the traces started from.I tried bridging the the 1-3mm gaps with a piece of lead from 1/8W resistors, and-some are side by side so it's super hard not to end up with a solder bridge between them-it's such a small piece of lead, it's always sticking more to the iron than the trace/pin, and so it always going out of alinementSo I gave up again. Now I have a Andonstar 301 microscope. And that's like shaving in the mirror, I'm not used to that at all yet.So I could try adding more pieces of longer wire, tacking it on 1 end then back a few cm, I know I can do that, thats still hard tho, there's so little solder holding it on the chip.I have a hot airgun too now, I never back when I 1st messed it all up. It have now idea if it's safe to use the microscope even at max distance with it, and so I really better not, I'm not risking that.I don't have solder paste yet, it's on the way from China.If I use solder wick on a 1-3mm piece of lead, I'm sure that will never workAny advice is welcome.

author: Rasz
author_rank: Super Contributor
timestamp: September 22, 2018, 03:42:18 pm
content: Quote from: lordvader88 on September 22, 2018, 09:44:00 amyes, solder almost always goes in the direction of heatuse flux, put solder on the traces and wires first, try to heat the trace and then slide the wire in place
Elektro Automatik Power Supply PS3032-20B - Page 1
Forum section: electronics / repair

author: powertomi
author_rank: Newbie
timestamp: August 19, 2018, 09:20:01 am
content: Hi everybody!Please help me!I need schematic or service manual this PSU.Not powered on...Thaks for help!

author: coromonadalix
author_rank: Super Contributor
timestamp: August 19, 2018, 12:55:21 pm
content: could you show us inside photos, maybe its an rebranded model

author: mk_
author_rank: Regular Contributor
timestamp: August 19, 2018, 01:15:02 pm
content: Ask EA directly.Usualy their technical support is very helpful - even for parts no longer in production...

author: mahi
author_rank: Regular Contributor
timestamp: August 19, 2018, 03:53:54 pm
content: I agree with mk_. When my old EA Elektro-Automatik PS2316-050 lost a channel (long out of warranty) I mailed them for service documentation. While they did not have a real service manual available they promptly sent me the complete schematics which were very helpful in repairing the fault. I'm not sure they'll do that for devices that are still being manufactured/sold but it's worth a try.PS: You did check the fuse on the back, right?

author: powertomi
author_rank: Newbie
timestamp: August 20, 2018, 09:15:03 am
content: Thanks a lot!I try to ask for help from their technical support...

author: powertomi
author_rank: Newbie
timestamp: August 30, 2018, 08:15:06 pm
content: This is the aux power supply.When power on, the input power inceases 70 between 100 VAC first the aux power supply started, the Volt/Amper display lighting up.If the input voltage continue increases to 150 VAC the main supply wake up.Between the main output ( Red-Black ) jack I measured cca. 20 Ohm.Maybe this is a short circuit?Now the aux supply can't start- try per second...The support it has helped me so far...( sen to me the aux ps picture)It stopped a few days ago.I waiting...

author: coromonadalix
author_rank: Super Contributor
timestamp: August 31, 2018, 08:31:43 am
content: this section gives +15v, -12v and an unknown voltage at X17 pins , maybe guess 24vdc at leastand an control line going to the v35 diode.I see there is mention of an powerfail sense line tooIf you say you have an 20 ohms impedance at the psu main output, it is definitely an problem, maybe you have some diode protection shorted outTakes many photos of your boards and show us ... we could find something ?

author: powertomi
author_rank: Newbie
timestamp: August 31, 2018, 08:27:35 pm
content: Thank You for answer!Next week I send photos,In weekend I worked as sound technician ( lot music-not enough sleep )...

author: powertomi
author_rank: Newbie
timestamp: September 23, 2018, 07:20:03 pm
content: Here the pictures..

author: cvanc
author_rank: Frequent Contributor
timestamp: September 24, 2018, 01:50:28 pm
content: Looks like a nice supply, good luck with your fix.This is a little bit of a worry, could it be evidence of overheating/burning? Might want to remove & evaluate that inductor...
R&S SME03 boot up with "Unknown Interrupt" - Page 1
Forum section: electronics / repair

author: mrf245
author_rank: Regular Contributor
timestamp: September 22, 2018, 01:23:08 am
content: Hello,I have a SME03 with failed CPU board battery. After replaced battery, when boot in to system, it noticed that need do self-calibration. OK, so I made it.But after finished calibration, when cycle-power, it stopped with "Unknown Interrupt (Vector 0) at 08049C34h". if cycle-power again, it can boot successfully, but seems SME03 has no save calibration data...What should I need to to next?Thanks!
3-pin Molex power header? (board mount) - Page 1
Forum section: electronics / repair

author: Skidlz
author_rank: Newbie
timestamp: September 22, 2018, 12:49:42 am
content: Hey guys,I'm building an old DIY computer from some design PDFs and it calls for a power header that I can't find. It's a 3 pin, .2" spaced Molex connector (common enough), but it's board mount.I can't find any mention of this header outside of the image I've attached. Can it still be found, or should I give up and use something more conventional?Thanks
Hantek DSO5072P oscilloscope channel 1 drift - Page 1
Forum section: electronics / repair

author: matt6ft9
author_rank: Contributor
timestamp: September 20, 2018, 04:03:47 pm
content: A week old DSO5000P Series (from Hantek) oscilloscope seems to have a channel 1 offset based on the heating inside the oscilloscope. (The scope is in a climate-controlled office)The drift occurs if no probes are attached, if a grounded probe is attached, etc. The drift occurs only on the 5V and 10V per division setting. (A relay inside the scope can be heard clicking when going from 2V/division to the 5V/division setting) When powered on, the offset is mean value of -1.8V, by the time it heats up, the offset is then zero. (the offset has been as low as -2.2V)The firmware is “3.40.0(180120.0)”, which seems to be the latest on the web site. The self calibration under “utility” -> “self calibration” has been run many times.Channel 2 seems to work great, no offset/heat issues. The fan in the scope is operationalHas anyone else had this problem with a self-heating offset on this scope?If there is a simple fix, I would like to try it. (or if it is a user error issue) Otherwise, I will send the scope back and see if the next one has the same issue.Matt Meerian

author: matt6ft9
author_rank: Contributor
timestamp: September 21, 2018, 08:59:39 pm
content: Update:The channel 1 schematic/iinfo was found here:https://www.eevblog.com/forum/repair/hantek-dso4072c-oscilloscope-both-channels-bad/By releasing small amounts of freeze spray, it looks like the AD8370 (750MHz op-amp) is source of the problem. In single quantities, the opamp is a $10.74 part on Digikey. During normal operation, both the AD8370’s on channel 1 and channel 2 operate at about 56C. (a thermocouple was used to find the temp)‘time to send it back.Matt