hybridfree/eevblog-posts huggingface dataset:
HP8648A Repairing flex PCB, ideas? - Page 1
Forum section: electronics / repair

author: Mr Simpleton
author_rank: Unknown
timestamp: September 05, 2013, 12:08:51 am
content: OK, so I got a nice lil' signal generator... and at first all looked fine, but realized some of the front panel buttons were not responding. It is rubber buttons that comes in contact with a conductive pattern on a clear flexible plastic carrier. After some digging I found that one of the conducting traces leading to some of the rubber buttons had a very very thin crack. Not even visible with 3x loupe, but verified with tracer. What would be the best way to repair? Conductive silver paint?? It's not the actual pattern behind the button but the trace towards the button. Soldering may be a bit risky, wouldn't the plastic sheet melt?

author: free_electron
author_rank: Super Contributor
timestamp: September 05, 2013, 01:13:39 am
content: conductive silver paint.if you touch it with a soldering iron it will go 'poof' and then it is game over.

author: edpalmer42
author_rank: Super Contributor
timestamp: September 05, 2013, 01:21:19 am
content: You could use the paint that's used to repair the rear window defrosting grid in a car. It's basically copper rather than silver and it's produced in greater quantities so it'll be cheaper than the silver paint.Ed

author: Mr Simpleton
author_rank: Unknown
timestamp: September 05, 2013, 08:09:17 am
content: Silver paint it isGood feeling now that I did not bring out the soldering iron despite 2 am and brain in hibernateOnly need a ml or so...
Samsung Laser Printer HVPS (High Voltae Power Supply) board repair - Page 1
Forum section: electronics / repair

author: Shivram10
author_rank: Contributor
timestamp: September 03, 2013, 08:16:13 am
content: Hi friends,One of my friend is having a Samsung ML-2851ND laser printer, which was working fine suddenly the printer software (Smart panel) on the computer started showing "Door Open" Error, he tried reopening and closing the front door & rear door it didn't work, then tried different cartridge, connected to different computer, it still did not work, then he showed the printer to some Computer repair shops, they said the Printer HVPS (High Voltae Power Supply) board is faulty and the company has discontinued the product and the spares are costly.He was about to scrap the printer away so I bought the printer from him.I checked the printer by connecting it to my computer, it was giving me the same problem. I opened the printer's HVPS board to check if it was burnt, it was clean. Here is the photo of the HVPS boardThere is no model number or anything on the board, only mentiones it as "PLOVER HVPS Rev 1.1"I checked the continuity of the switches (red circled) as shown in the photo below.I desoldered both the switches and checked the continuity, they were working fine. I also taped both the connectors and reconnected the card on the printer but it was still showing the Door Open error. So I figured it has some faulty components on the board.My question now is, can the HVPS board be repaired as getting a new board is costing half the price of printer.PS - The photos of the HVPS board are from the internet as I didn't have my digital camera with me and the photos from my cell phone were not clear.

author: amyk
author_rank: Super Contributor
timestamp: September 03, 2013, 01:15:01 pm
content: If you trace where the tracks on the switches go I bet they run directly to the connector so it's not related to any other components on the board.Are you sure both switches are getting actuated when the door is closed?

author: Shivram10
author_rank: Contributor
timestamp: September 03, 2013, 02:37:00 pm
content: QuoteI had put tape on both the switches (in red circle) and closed them even then it was showing door open..
Repair Denon Amp, Stuck for Diodes. - Page 1
Forum section: electronics / repair

author: Sirus
author_rank: Contributor
timestamp: August 29, 2013, 12:52:35 am
content: Freind asked me to fix his 80's Denon PMA-535R. He tried to fix it himself by putting a higher rated fuse so it blew more than just the output transitors. I have sourced all the parts needed apart from the diodes.I need2 of MTZJ27A Zeners (Digikey have them but only in bulk, £70 for loads)2 of 1ss252 that no longer exist.Does anyone know what equivalent diodes I can buy in small quantitys?Digikey was the only one that had all the sanken transitors I needed, so I would prefer the diodes came from them to keep delivery charges down.Thanks Muchly

author: c4757p
author_rank: Super Contributor
timestamp: August 29, 2013, 01:03:11 am
content: 1SS252: 4ns recovery, 90V, 130mA.1N4148: 4ns recovery, 100V, 200mA.MTZJ27A: 27V @ 45mA.BZX85B27: 27V @ 41mA.Edit - Looks like DigiKey doesn't have the BZX85B27 at all (Mouser has thousands). 1N4750A is not as close a match, but should work.But did it really blow all these parts...? I'm a bit surprised at these diodes, I don't think they'd be in a part of a circuit that would blow up in this case.

author: Sirus
author_rank: Contributor
timestamp: August 29, 2013, 01:50:29 am
content: Thanks for the help.Yup they have gone tit's up, the other channel is a handy place to check as that side is working fine. That had a repair done on the output transitors at some point as the date codes are '93 opposed to '89 on the blown channel. The diodes are back to back on the output bases. Looking at the circuit diagram, not the best, but was free from hifiengine.com, that should be as far back as the damage goes. I can't test any further back as the circuit needs to operate for some of the voltage tests and I can't see anything on the schematic to get damaged any further back. I'm doing it for £40 plus parts (£15), more of a hobby jobby
TEK 465 repair of DM44 unit  Searching for LD111A  - Page 1
Forum section: electronics / repair

author: CalG
author_rank: Contributor
timestamp: August 27, 2013, 06:31:57 pm
content: Hello,New to this forum and I'm not much good at electronics, but I try ;-)I'm trying to bring a recently failed VFD back to life, and pulled out the TEK 465 to poke around on the control boards. I've replaced a pair of diodes and a small cap, but have yet to discover the failure. Typical....What I did discover is the DM 44 section on the TEK465 is on the blink. It has had problems in the past that have been made right by re-seating the A_D converter IC.A pass through the service pages for the DM44 points to the A-D converter area. The IC is a LD111A . I have not been able to locate 1 piece to replace this suspect device.On line brokers seem to go for higher part qty.Also, It appears that the LD111ACJ is the present day replacement. TRUE? a direct interchange?Suggestions on source or replacement part?TIACal
Calibration and Repair Services - Page 1
Forum section: electronics / repair

author: prestigetest
author_rank: Regular Contributor
timestamp: August 20, 2013, 06:31:39 pm
content: Good Afternoon Everyone,If you are looking for calibration or repair services in the US, I can help you out! Prestige Test Equipment, Inc. offer's free repair evaluations on most test and measurement models. If you have an issue with any of your gear feel free to send it in to us and we will provide a repair estimate. If you are not happy with it, we will ship it back to you. Your only cost is shipping and handling and return shipping.Prestige Test Equipment, Inc. can also provide NIST Traceable calibrations! If you have an item that has been out of calibration for some time, feel free to send me a message with it's model number and any options installed on it. I will respond with pricing for that item as well as a lead time. All of our calibrations are for a 1 year cycle and come with a certificate of calibration as well! Turn-around-times on calibrations are typically 3 days or less!Best Regards,Zach YoungPrestige Test Equipment, Inc.321-972-1010
Flat Flex Cable repair in the field - Page 1
Forum section: electronics / repair

author: sequence
author_rank: Newbie
timestamp: August 16, 2013, 12:00:42 pm
content: Hi,Could someone please point me toward a technique for repairing simple FFCs quickly? My general use case is the repair of 4-8 pin cables in laptops and cell phones, normally after someone else was less than gentle with them. I ran across this problem 5 times last month, and waiting for replacements is a serious pain. I've been using fine sandpaper to expose the traces, then applying conductive epoxy and kapton tape, but is there a product that maybe has pins that stab through both ends of a broken cable to connect them? I give full disclosure about the nature of these hacky fixes and try to replace them with proper FFCs, but a better repair solution would be highly appreciated.Thanks!

author: Psi
author_rank: Super Contributor
timestamp: August 16, 2013, 12:05:14 pm
content: Quote from: sequence on August 16, 2013, 12:00:42 pmI did exactly that to fix an old Logitech computer keyboard. Pushed a pin through the flex on each end, dab of hot glue and then soldered a wire between the pins. Worked perfectly.I dunno how easy it would be on a fine pitched flex though.

author: sequence
author_rank: Newbie
timestamp: August 16, 2013, 12:29:23 pm
content: Hot glue is the missing link, thanks! I'll get some pins and practice a bit, then.

author: robrenz
author_rank: Super Contributor
timestamp: August 16, 2013, 01:17:34 pm
content: Checkthis postand the whole thread

author: Psi
author_rank: Super Contributor
timestamp: August 19, 2013, 09:14:09 am
content: Just remember to check the metal pins your using are solderable.
LeCroy 25MHz HV Differential Probe Teardown / Repair - Page 1
Forum section: electronics / repair

author: andyb
author_rank: Regular Contributor
timestamp: August 16, 2013, 08:01:39 pm
content: Hey guys, I know there's been some talk about differential probes, and I managed to score a busted one off the 'bay. I tore it down and attempted a repair on my websitehttp://bardagjy.com/?p=1664I haven't yet attempted calibration, curious to hear your suggestions.

author: ivaylo
author_rank: Frequent Contributor
timestamp: August 17, 2013, 07:20:31 am
content: This looks exactly like the BK Precision PR-60 and the Agilent N2791A probes. And same 25MHz, 700V spec and everything (it ain't Agilent nor Lecroy, would BK be the OEM?). In case you find service manuals for those or something. I do have the BK precision one, may open and see if they sanded off the chip ids. Looking at yours, almost certain they did though...

author: qno
author_rank: Frequent Contributor
timestamp: August 17, 2013, 09:18:21 am
content: They all come from Sapphire.http://www.sapphire.com.tw/I have one for many years. They used to put the name Sapphire on the PCB.

author: andyb
author_rank: Regular Contributor
timestamp: August 17, 2013, 05:37:01 pm
content: Qno, good find! There's a calibration procedure in their service docs.Funny that they have a flashing notice about how their products have been cloned by Pintech..

author: M. András
author_rank: Super Contributor
timestamp: August 17, 2013, 05:55:49 pm
content: hmm wonder what is their price directly from the oem

author: plesa
author_rank: Frequent Contributor
timestamp: August 17, 2013, 07:29:04 pm
content: Quote from: M. András on August 17, 2013, 05:55:49 pmhttp://www.caltestelectronics.com/ctitem/21-probe-oscilloscope-differential/CT2593-1320USD

author: Dave
author_rank: Super Contributor
timestamp: August 18, 2013, 12:04:41 am
content: Quote from: plesa on August 17, 2013, 07:29:04 pm

author: tinhead
author_rank: Super Contributor
timestamp: August 18, 2013, 12:40:09 am
content: Quote from: andyb on August 17, 2013, 05:37:01 pmright, and Pintech is using as well name Pintek and DKFlex (.com). But the at least very honest - Beyond Innovation, right, copycat is beyod any innovation!
Anritsu 68000 69000 generator series hack/repair - Page 1
Forum section: electronics / repair

author: dir
author_rank: Newbie
timestamp: August 15, 2013, 11:43:13 pm
content: Does anybody here have some schematics of these generators? Or does anybody know where can I get one A17 card for these generators ?I have one generator with the A17 missing. It is the CPU board which also contains the operating system and calibration data. I am thinking that if I cannot get a board I could make a controller to replace it.
Agilent E3614A Repair - Page 1
Forum section: electronics / repair

author: Cigarsnob
author_rank: Regular Contributor
timestamp: June 04, 2013, 09:03:38 pm
content: Hi,I am looking for the schematic for the Agilent E36XXA display circuit. Does anyone know where I can find this? I've done a google search and didn't find much. Went to Agilent's site and picked up the service/operating manual, but they only have the schematic of the power supply.I also called Agilent and spoke with an Applications Engineer and someone else. They couldn't find the schematic on their site nor are they sure a schematic is available.Any ideas?Thanks,Phil

author: wraper
author_rank: Unknown
timestamp: June 04, 2013, 10:06:01 pm
content: Why do you need it at all? There is nothing specific, only two ICL7107. It's basically this schematic plus some other components.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: June 04, 2013, 11:14:35 pm
content: Quote from: wraper on June 04, 2013, 10:06:01 pmThe E36xxA display series did not use the integrated chip like the ICL7107. Instead it's all broken out into their respective chips. But you're right, it's more or less similar to the schematic that you provided. Just a bit more that's all. I was manually tracing the current signal to it's ADC and other traces and I was just hoping to save time by having a schematic to look at instead of drawing it myself.The main reason why I wanted the schematic is because the current display does not display, but the proper current is being provided when connected to an current meter.Thank you for the schematic though

author: wraper
author_rank: Unknown
timestamp: June 04, 2013, 11:46:00 pm
content: I just teared apart my one month old E3611A and there are two ICL7107 from microchip. E3614A seems to have the same display board, or maybe I'm wrong? Maybe on yours they are under HP own part numbers, not original marking...

author: Cigarsnob
author_rank: Regular Contributor
timestamp: June 05, 2013, 12:15:13 am
content: If I'm reading the date codes correctly on some of these ICs, it seems like this power supply was born sometime in 2003ish.My display board has TC14433 from Microchip as the ADC and then all the other supporting circuitry/drivers. It's an Agilent marked display board, so I'm guessing they changed their design sometime after 2003ish.

author: wraper
author_rank: Unknown
timestamp: June 05, 2013, 12:33:54 am
content: Anyway it seems quiet simple. Not much things to go wrong. There are couple of schematics in datasheet with different display drivers. Checking TC14433 should be really easy, and LED driver even easier than that.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: June 05, 2013, 01:12:46 am
content: Thanks Warper

author: free_electron
author_rank: Super Contributor
timestamp: August 11, 2013, 01:48:51 am
content: those boards use the teledyne a/d converter. borged by microchip
HP 6632B  Needs Repair  [UK] - SOLVED - Page 1
Forum section: electronics / repair

author: dans34
author_rank: Newbie
timestamp: August 18, 2013, 10:41:32 am
content: i have this HP 6632B psu that when its turned on (after the self test) it shows 0.0007v 0.0004a on the display ,When you set a volatage and connect the load its fine for around 20~30s but then it switches to CC and the voltage dropsI lack the electronical knowlage to diagnose the issue , does anyone know of a repair place in the UK (preferably in the North Yorkshire Area) that could take alook at my unit ?

author: gerrysweeney
author_rank: Regular Contributor
timestamp: August 18, 2013, 10:52:48 am
content: Are you sure thats the right model number, I tried googling it but could not find it.Gerry

author: KJDS
author_rank: Super Contributor
timestamp: August 18, 2013, 10:56:42 am
content: That's not an a HP part number.

author: dans34
author_rank: Newbie
timestamp: August 18, 2013, 11:14:28 am
content: sorry its 6632b

author: KJDS
author_rank: Super Contributor
timestamp: August 18, 2013, 11:27:50 am
content: The service manual is available here.http://cp.literature.agilent.com/litweb/pdf/5962-8119.pdf

author: dans34
author_rank: Newbie
timestamp: August 18, 2013, 11:44:10 am
content: Quote from: KJDS on August 18, 2013, 11:27:50 amthanks , i just realised it was you i bought it offits been working fine for the last few months then i tried to charge an older 19v tablet pc with it (i stupid idea) since then ive had the issue abovei have followed as much as i could from that service manual , even checking that the output terminals are not shorted but still no dice

author: KJDS
author_rank: Super Contributor
timestamp: August 18, 2013, 11:54:32 am
content: I'm sure you've done this already, but have you set the current limit to 5A?

author: dans34
author_rank: Newbie
timestamp: August 18, 2013, 12:22:14 pm
content: Quote from: KJDS on August 18, 2013, 11:54:32 ami just set that up and now it seams to work fine , looks like it was an id 10 t errorhowever it still shows 0.0007v 0.0004a on the display after the self test (but thats not a problem)

author: AndyC_772
author_rank: Super Contributor
timestamp: August 18, 2013, 12:40:43 pm
content: That's just a very slight calibration offset error, nothing to worry about. I have 3x 6632B's and 1x6634B, and none of them show 0.0000V and 0.0000A when switched off.

author: dexters_lab
author_rank: Unknown
timestamp: August 19, 2013, 08:09:56 pm
content: Same on mine, figured it was a cal issue. Nice to know thats all it is
FS: BGA rework station PCB repair machine - Page 1
Forum section: electronics / repair

author: coalago
author_rank: Contributor
timestamp: July 28, 2013, 10:17:15 am
content: Hello, ladies and gentlemen,Here offer BGA rework stations,different kinds prices available. Directly from factory, 8 years manufacture experience,cost-effective.Welcome to enquire~Here I introduce a kind ( stock 5 units) :1.Intelligent thermal fuse, it doesn‘t work when fan no working.2.Three independent heating zone, suitable for lead free process3.It adapts quality heating material in 1st and 2nd heating zone, which produces hi temperature and breeze, and far IR for 3rd heating zone pre-heat to prevent PCB deformation.4.Upper heating system can be moving fro and back,up and down, and the bottom heating system can go up and down.5.Sound hint function.6.PLC control, 7 inches touch display desk.7.Big flow constant current. Cools PCB for better welding effort after Heating finish , prevent PCB deformation.8.Portable vacuum pen takes out BGA.convenient and durable.9.Special pallet for different main board.10.Various sizes heating nozzles, or custom made.
HP 427A Voltmeter Repair – Q6 FET SU527 Replacement - Page 1
Forum section: electronics / repair

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: July 25, 2013, 02:29:17 pm
content: I purchased an HP 427A voltmeter from eBay but it's not working. Inspection showed that Q6, an SU527 from Siliconix, had one lead connected to the circuit board, one lead floating in air, and the third lead broken off flush with the case. Since this is the impedance converter, I guess it's not too surprising that the meter indicates mid scale no matter what's connected.I can't locate any information on the SU527 – the only web reference is to the HP 427A service manual. Can anyone suggest an alternative part?The attachments show the damaged part and the section of theservice manual schematic.Thanks in advance!

author: david77
author_rank: Frequent Contributor
timestamp: July 25, 2013, 02:36:01 pm
content: I'd just try a generic FET like the 2N7000 or a BF245 or something.

author: fpliuzzi
author_rank: Regular Contributor
timestamp: July 26, 2013, 01:12:46 pm
content: Hello,I noticed in the HP427A servive manual that the HP part number for the SU527 P-channel JFET is 1855-0023. There's a downloadable 143 page HP components cross-reference listed at this link...www.sphere.bc.ca/test/hpparts.html#crossUnfortunately, of all of the thousands of components listed in the pdf, HP part number 1855-0023 is not included there. On page 16 of the 143 page pdf HP states that components that were made exclusively for HP (presumably having certain characteristics such as this JFET maybe having a particulartly low Cgs for example) are not included in this xref.(you may still want to download the pdf file because it may prove helpful in the future)--------------------------------------------------------------------------------------------------------------It would be pretty pricy when you include shipping, but it seems that Tucker Electronics has the HP 1855-0023 in stock at $5 each.www.etestparts.com/Search.aspx?Search=1855-0023---------------------------------------------------------------------------------------------------------------Also, like david77 previously mentioned, you very well may be able to get away with using an appropriate generic p-channel JFET for Q6. The meter may work fairly well with a substitute Q6, but just not quite meet all of its published performance specifications.By the way, I really like HP meters from that era. My HP410c's 700MHz bandwidth really comes in handy sometimes. Good luck with your meter repair.Regards,Frank

author: Grayfox
author_rank: Regular Contributor
timestamp: July 26, 2013, 02:11:38 pm
content: http://www.ctg123.com/rapid-quote-system/request/?p=SU527
How to repair bent rotary switch shaft? - Page 1
Forum section: electronics / repair

author: skipjackrc4
author_rank: Regular Contributor
timestamp: August 26, 2013, 02:40:33 am
content: I recently got one of the EDC MV-100 voltage "standards" on eBay. Unfortunately, the most significant digit's rotary switch has a bent shaft, and refuses to turn more than a couple positions. The knob was also shattered, but I can replace that easily enough.Does anyone have an idea on how to repair this? I have never attempted to straighten a shaft like this out before.I have attached a pic of the switch. I can always buy a replacement 11 position switch, but good ones are expensive and I would rather keep the original one if possible. Thanks in advance for any advice!

author: skipjackrc4
author_rank: Regular Contributor
timestamp: August 26, 2013, 02:50:56 am
content: Now for the pic...

author: WarSim
author_rank: Frequent Contributor
timestamp: August 26, 2013, 03:18:41 am
content: Quote from: skipjackrc4 on August 26, 2013, 02:40:33 amThat switch is built from parts. It can be disassembled and the shaft can be replaced. Some parts snap into seats but can be unseated, but most assembly is via tabs. These days the shafts have gotten more expensive. If too expensive you will have better luck straightening the shaft when removed.

author: lowimpedance
author_rank: Super Contributor
timestamp: August 26, 2013, 03:23:26 am
content: No chance of finding a suitable size switch plate in a surplus junk store (depends on your location i guess) !!. Probably easier than to repair this one.Who is going to see it when the covers are on and if functionality is restored does it matter if the switch plate is not original.If not then remove the bent one and attach to a suitable bar of metal, which can be held in a vice. So the threaded portion is supported then use a small- ish adjustable spanner fitted over the bent bit (end on) and try to carefully bend it back to as straight as your going to get it. Use some emery to polish the shaft. Nothing to loose anyway at having a crack at it, good luck.Btw the shaft has a clip at the end of the thread section to retain it in the mounting plate, unfortunately here your shaft is bent so removing the shaft to work on it only will not be possible.

author: free_electron
author_rank: Super Contributor
timestamp: August 26, 2013, 04:54:31 am
content: digikey still sells that kind of switch. buy one , rip shaft out, replace.

author: G7PSK
author_rank: Super Contributor
timestamp: August 27, 2013, 08:12:40 am
content: That shaft had quite a bash, if you manage to straighten it or find a replacement you will more than likely find that the bushing itself is also deformed also the outer end of the switch would also have exposed to high forces that will have caused distortion.But the correct way to straighten a shaft is not by holding in a vise and then bending it with a piece of tube fitted over the end, you should lay it on a hard flat surface and tap the shaft with a soft face hammer at the high point turning the shaft as required to keep the highest point upwards with frequent sighting along the shaft to check for straightness.
Attempting to repair an insanely cheap LCD display (why the waste? ) - Page 1
Forum section: electronics / repair

author: Razor512
author_rank: Regular Contributor
timestamp: June 05, 2013, 04:23:21 am
content: An 8 inch LCD panel failed on me (Display came with a $200 4 security camera + 500GB networked DVR)I noticed, 2 different ribbon cables (same pin count), Only issue is that the transparent ribbon cable is long enough to reach the connector on the PCB. The LCD is obviously designed to be as cheap as possible, so why add that extra bit of stuff?The extra PCB has no special components on it.I attached 2 images of the seemingly unnecessary part.Overall, why the waste?(click for full size)LCD-1byRazor512, on FlickrLCD-2byRazor512, on Flickr

author: amyk
author_rank: Super Contributor
timestamp: June 05, 2013, 09:12:05 am
content: There might be several other models with a similar BOM, and the extender PCB + connectors might've been cheaper than ordering another custom length of flex.Or maybe it's a debugging facility of some sort...

author: bilko
author_rank: Frequent Contributor
timestamp: June 05, 2013, 09:18:00 am
content: It looks like it might be an extender cable to allow board testing. Should have been removed before assembly

author: ptricks
author_rank: Frequent Contributor
timestamp: June 05, 2013, 10:53:19 am
content: The type of connector that is on the LCD is very fragile and while it might reach , someone assembling it without that board in between could easy damage it.

author: Rufus
author_rank: Super Contributor
timestamp: June 05, 2013, 11:46:17 am
content: Looks like it might be too short for easy assembly without the extension. Otherwise FPC cables and connectors have contact up and contact down styles which the board and cable might be changing.

author: Razor512
author_rank: Regular Contributor
timestamp: June 06, 2013, 07:59:33 pm
content: Seems that I am unable to fix it, all of the passives seem to work so it most be that crappy SOC that reaches around 70C after a minute or 2 or being on and displaying a black screen with no OSD.Guess I will have to look for an old portable TV or something else thats cheap to use as a display when not monitoring from my computer or tablet or smartphone.

author: amyk
author_rank: Super Contributor
timestamp: June 07, 2013, 12:41:04 pm
content: Have you checked the caps? Might be too much ripple?FYI here's datasheet and related documents on the IC...http://cache.ourdev.cn/bbs_upload782111/files_49/ourdev_706832C2JGB9.rar
Keithley 6485 repair - Page 1
Forum section: electronics / repair

author: plesa
author_rank: Frequent Contributor
timestamp: May 28, 2013, 06:48:27 pm
content: Last week during measurement I accidentally applied 2.5 kV to input terminal of this picoammeter. After accident I power on flickering numbers were on display.So I take it apart to see if I can fix it.The input stage contains LMC6061 and LMC662, these two opamps were first things which can be fried.When I tried to create the schematic I also found fried 1k resistor on input (not visible) only the value were totally out of value on package (R110).I power it and found that on power supply +/-5V rails is voltage bellow 1V (measured on testpoints TP1,TP2).So I try to find the lowest possible resistance on supply rails, it was around array of FETs for relays switching.I decided to solder the wires and test which componets consume so much power and bang. It was comparator LM393.After replacing 4 components the meter is fully working!!Do not forget to clean all flux residues with IPA and use gloves during repair. I can recommend the bake at 60°C for an hour.I tested it with my 2636 and it seems to be still in spec.I hope that this will someone help to repair this meter.It is quite useful meter with internal math function in can be in second switched to high input resistance voltmeter (I'm using 250M Caddock or 1TOhm array) or to high resistance measurement.The internal math function can also display the proper units and prefixes ( V, Ohm, etc).
TRIO CS-1650A repair advice request - Page 1
Forum section: electronics / repair

author: wilfred
author_rank: Super Contributor
timestamp: April 20, 2013, 06:58:06 am
content: /.

author: mzacharias
author_rank: Frequent Contributor
timestamp: April 25, 2013, 01:18:37 am
content: For gosh sakes. Clean the controls. Couldn't be more obvious.
Repairing LCD monitor - Page 1
Forum section: electronics / repair

author: sean87
author_rank: Regular Contributor
timestamp: April 14, 2013, 07:56:23 pm
content: Hi guys,There is a Samsung S22A300B monitor that I am trying to diagnose and possibly, repair.The monitor has DVI and VGA inputs. It runs from an external 14V/2.5A DC adapter.When there is no video cable connected (DVI and or VGA), the monitor goes to self test mode as expected...showing that famous screen with title "Check signal cable" and 3 RGB squares. In this mode everything is normal, the backlight is also on and no problem...As soon as I connect either DVI or VGA or both of them (of course on the other end these cables are connected to PC and pc is ON), The backlight goes off, screen becomes black, but the LED for power on, on the monitor remains ON.I've cracked the monitor open and there is only a tiny PCB for the connectors and some circuitry and sockets for backlights. There are some test points like 3.3, +5, SDA, SCL and LED that multimeter shows they are fine.The only thing I could notice, is that one of the chokes is a little bit sticky, and it produces more noisy sound than the other chock.There is also a solid capacitor that I believe is in series with the DC input jack...the multimeter shows 14.5 volts across this cap. It is also has something like what normal electrolit capacitors have on their top...some sort of breathing crack!!!! Maybe the pictures can speak better.Any ideas what can be wrong? What kind of other tests I can do to get closer to the failure reason?I am sure this is not the problem of my PC, I have 2 other (different) monitros that still work fine with my PC....this one just suddenly died or faked death in a beautiful sunday morning

author: sean87
author_rank: Regular Contributor
timestamp: April 14, 2013, 08:27:22 pm
content: I have a feeling that something is going wrong under the metal shield, but it is almost next to impossible to desolder this metal shield...even with my soldering iron at 420 degrees this solder joints are not even melting!

author: sean87
author_rank: Regular Contributor
timestamp: April 15, 2013, 08:26:08 am
content: Nevermind, I found that this is a common problem with SA300 series of monitors...there is only one soloution and it is to update the monitor firmware (YES! using vga cable!) ....I did that also but it didn't help...

author: Alana
author_rank: Frequent Contributor
timestamp: April 15, 2013, 12:02:34 pm
content: I have 2 samsung LCD's from dumpster diving - one had cracked solder in the connectors from connecting and disconnecting cables frequently. Behaviour like in yours. Solution - even if it looks ok resolder each pin with normal leded solder and check for pcb traces that may have gone bad.There should be bunch of input protection diodes [transils?] in SOT23 packages near VGA and DVI - at least this was a case in my LCD.Other - bad solder, propably within firmware chip. Reflowing this chip fixed a problem.Try both solutions, one may work for you.

author: madires
author_rank: Super Contributor
timestamp: April 15, 2013, 01:03:25 pm
content: Quote from: sean87 on April 14, 2013, 07:56:23 pmIt's a fuse ;-)
Tektronix AM503B error 592 - repairable? - Page 1
Forum section: electronics / repair

author: atsthng
author_rank: Contributor
timestamp: April 02, 2013, 08:03:10 am
content: Hi,Have the option of buying a faulty Tek AM503B. Apart from a NVRAM error on power up, the significant issue with it is a burnt smell and overheating when powered up, and error 592 when the Degauss / Autobalance button is pressed.Is there a chance this is repairable? There are no service manuals with schematics for the 503B, only for the predecessor 503A. Are the two close enough that I can use the 503A service manual to have a go at repairing the 503B?Thanks!

author: ddavidebor
author_rank: Super Contributor
timestamp: April 02, 2013, 10:22:55 am
content: Never buy broke stuff without the service manual.

author: atsthng
author_rank: Contributor
timestamp: April 02, 2013, 05:32:42 pm
content: Went ahead to buy the AM503B. Yes, curiousity and optimism that it would be a simple fix trumped good judgement. Didn't need any schematics after all - sniffed around - unfortunately what burnt looks like a custom asic. Oh well, parts :-)I haven't seen this kind of IC interconnect before, so I figured I might as well share some pics.

author: atsthng
author_rank: Contributor
timestamp: April 03, 2013, 05:46:10 pm
content: Thanks, I have the AM503 but it is significantly different from the AM503B which is not working. The fried chip does look like it is part of the output amplification (the output connector is connected to it) but unfortunately the schematics for the B model don't appear to have been released by Tektronix.
(Video) Repair of a Harman/Kardon AVR 130 - Page 1
Forum section: electronics / repair

author: Madsaaby
author_rank: Regular Contributor
timestamp: March 28, 2013, 09:40:46 am
content: Hey guysShot a video of repairing my dads Harman/Kardon AVR 130 Surround Receiver.Professionals may not learn much from this, since I'm not one myself.But you are of cause welcome to watch it anyway..Hope you like ithttp://youtu.be/at7GLypcLro-Mads
Datron 1281 Meter Repair Help - Page 1
Forum section: electronics / repair

author: starjohn
author_rank: Newbie
timestamp: April 29, 2013, 09:11:18 pm
content: I am working on a Datron 1281 meter.DC voltage calibration at 10v functions ok, but the Internal source calibration failed.This Meter has the following errors after Internal source calibration.Error codes:2202 1Kv Range zero magnitude test (P028).2192 100V Range zero magnitude test (P021).2162 10V Range zero magnitude test (P006).Is there anyone that has experience in repairing these instruments?Thanks,John
Flat cable repair - Page 1
Forum section: electronics / repair

author: EB5AGV
author_rank: Contributor
timestamp: March 09, 2013, 10:39:05 am
content: Hi all,I found an apparently joy-stopping problem during a recent repair, but managed to solve itHere you have my ramblings about it. I hope it helps to other people with similar problems:http://www.jvgavila.com/flat_cable_repair.htmBest regards,JOSE

author: David_AVD
author_rank: Super Contributor
timestamp: March 09, 2013, 10:42:31 am
content: Well done! I don't think I would have had the patience and just sourced a new cable myself.

author: SeanB
author_rank: Super Contributor
timestamp: March 09, 2013, 10:52:10 am
content: Well done, I normally look in the box of scrapped flat cables ( I keep them quite often for this reason) for a cable that is either the right number of ways or a few extra that can be cut down to fit and that is as long or longer by not much.

author: flolic
author_rank: Frequent Contributor
timestamp: March 09, 2013, 11:49:00 am
content: Well done!I repair flat cables all the time, but on a much smaller scale

author: EB5AGV
author_rank: Contributor
timestamp: March 09, 2013, 11:55:38 am
content: Hello!Quote from: flolic on March 09, 2013, 11:49:00 amWell, it is a similar repair, but on a different place, in the middle of the cable. I have done also some of these (perhaps not so tiny) but had never done or seen the one I depicted. There is no doubt somebody else has done it before, but I wanted to share it with the worldRegards,JOSE
iPod nano 6g headphone jack repair - Page 1
Forum section: electronics / repair

author: Haze
author_rank: Newbie
timestamp: March 01, 2013, 02:03:56 pm
content: hi,my iPod nano 6g headphone jack broke about 2 months ago.The problem at first only was that when I take the headphone plug out of the jack the music would not stop playing, which would result in an empty battery the next day.I continued using the iPod till several weeks ago the button to turn up the music broke as well.I checked the local store for repair cost which would have been 80 Euros so i got a replacement jack on amazon.The headphone jack is attached to the volume buttons including power button.Now after replacing the jack, the buttons work but the music "quality" if u can call it that:) is terrible well actually not evan there.Where ever i plug my ipod into it sounds like the speakers are blown, where as they work with other devices.Headphones as well sound blown and fuzzy.What do you think could have gone wrong?I already replaced the isolation tape in the iPod.Could I have broken some cables?im addicted to musicso pleaz help me:D
Power Supply Repair Help - Page 1
Forum section: electronics / repair

author: Stephenniall
author_rank: Contributor
timestamp: February 20, 2013, 02:23:32 pm
content: Hi !I'm looking for a little bit of help with a repair. I bought two of these power supplies off E-Bay a while ago for the massive sum of £10, And one of them has developed a fault in the last week.It was working fine one day, Then the next day when i powered it up all the relay started to click erratically, and the voltage kept fluctuating up to around 20 volts. This power supply is a dual supply, so has two power boards inside, One per rail (Is rail the correct word?).The relay wasn't clicking on one rail, so I'm guessing it was just this board that's broken. I've took the board out for a look, The power supply uses four 2N3055 transistors for the main power, I don't know the make of the supply, all i know is it is a model LC-1522, And was sold bu SJ Electronics here in England, It was an ex College power supply so has probably been battered all its life by college students.I'm not too sure on what the relay does, Somebody told me it's to switch the mains transformer taps to different voltages, which seems appropriate...Does anybody have any ideas on how to troubleshoot this, Should i replace the relay, or do you guys think it's something else ?Please excuse my bad pictures, They were took with my phone !This is the front of the unitThis is the Inside.This is how it attaches to the transistors, The two boards are screwed on with solder tabs, and the whole assembly is slid into the power supply (I think its a rather neat design).This is the top of the broken boardAnd the relayAnd finally a picture of the bodge job done on the back, and all the flux residue!Thanks alot for looking, Hopefully i can have the unit working again soon.EDIT: It seems the forum has cut off some of my pictures, to see the full pictures you can click on my photobucket.http://s1081.beta.photobucket.com/user/Stephen-Niall/library/Power%20SupplyMany Thanks,Stephen.

author: Psi
author_rank: Super Contributor
timestamp: February 20, 2013, 09:04:24 pm
content: Quote from: Stephenniall on February 20, 2013, 02:23:32 pmThis could mean that one of the switches on the front panel is bad, or maybe a one of the pots is dirty and intermittent.

author: Stephenniall
author_rank: Contributor
timestamp: February 20, 2013, 09:49:44 pm
content: That's actually something rather simple which I've overlooked, I've just checked the resistance of the potentiometers and they seem fine. I'll give them a clean tomorrow and see if that solves the problem.Thanks,Stephen.
Spectrum Analyzer Repair Trick - Page 1
Forum section: electronics / repair

author: sherlock
author_rank: Contributor
timestamp: January 29, 2013, 09:14:19 pm
content: Hi All.... I recently bought a non-working Advantest 2.6GHz spectrum analyzer on eBay. Turns out the front attenuator diodes were fried along with the first mixer diode. I bought the resistors from Digikey and found a suitable replacement diode again on eBay. Still no signal display. The analyzer uses a mixer with the local oscillator running 2.6 GHzhigherthan the input signal, so the LO runs at 2.6-5.2 GHz. Since that was a possibility of no signal display, the manual says to check the frequency and amplitude. Well, nothing in my basement workshop, or at my work either, will measure anything that high. I thought of trying to make some kind of detector circuit from one of the mixer diodes I bought, just to see if the LO was present. I was guseeing that if its there, its probably correct. Then it suddenly dawned on me... I HAVE a microwave detector already! Went out to the garage and found my old radar detector that I used to use in the car. I fired that up with a 12VDC supply and put the antenna side directly over the mixer coupler. Viola' ! The radar detector sang like a bird! Now again I couldn't measure the frequency, but it was there! I managed to find out the remaining problem and now the analyzer seems to work fine. Just thought I'd pass that on in case anyone else could use it.sherlock

author: saturation
author_rank: Super Contributor
timestamp: January 30, 2013, 05:29:59 pm
content: ... great idea for a quick microwave detector from K and up.
Trade or sharing parts for repair work or just whatever it is needed for - Page 1
Forum section: electronics / repair

author: quarks
author_rank: Frequent Contributor
timestamp: January 28, 2013, 08:31:50 pm
content: Hello all,I wonder if anybody ever thought of trading/sharing parts and/or if this is a good idea or even manageable at all.I right now look for parts which are hard to find, because they are old or even obsolete. But maybe someone of you might have it, but nobody knows it and therfore can not ask.What do you think?byequarks

author: poorchava
author_rank: Super Contributor
timestamp: January 29, 2013, 08:52:17 am
content: I like the idea. I think this could be especially useful for people who find themselves needing to replace some unobtanium in old scopes or spectrum analyzers.Also, I don't know how does it look like in germany, but in many countries vast majority of the parts are not availabe from retailers, and digikey/mouser/rs has prohibitively expensive shipping and handling.I think that topic like "making large order from shop XYZ, who wsanna share s&h costs?" would be useful
Through plating repairs.  - Page 1
Forum section: electronics / repair

author: G7PSK
author_rank: Super Contributor
timestamp: February 27, 2013, 02:02:26 pm
content: Is there any way of replacing through hole plating on a pcb where the hole plating has come away on a 2 layer board. A cap has just blown on a DC to DC boost and the plating has been destroyed in removing the remains. The circuit works with the replacement capacitor but I have to have it sticking out so far to solder both sides that the unit wont go back into the case without the cap, which is slightly longer anyway, hitting the fan. I had wondered about drilling it out and soldering a small copper tube in but the smallest copper tube I can find is 5mm dia.

author: JuKu
author_rank: Frequent Contributor
timestamp: February 27, 2013, 02:04:36 pm
content: Drill a hole nearby, put a piece of wire trough and solder it to tracks on both sides.

author: G7PSK
author_rank: Super Contributor
timestamp: February 27, 2013, 02:24:15 pm
content: That's a good idea, I had not thought of. I Googled repairs and found eyelet kits but they cost many times the cost of the whole board, I know they repair more than one board but I only need to repair one or two like that in a year at the most.

author: smashedProton
author_rank: Frequent Contributor
timestamp: February 27, 2013, 02:41:54 pm
content: If you really want to do it right, you can line the hole with conductive ink, and electroplate it.

author: SeanB
author_rank: Super Contributor
timestamp: February 27, 2013, 03:41:20 pm
content: Drill it out to 3x the lead diameter and clean the top solder resist back then solder a few thin wire strands through the hole, leaving room for the lead of the capacitor. Then place the cap through and solder the bottom in, the solder will wick up the wires and make an eyelet. Otherwise the drill hole next to it and place a jumper is the best bet, if there is place for it. Solder the jumper wire to the capacitor lead after making an eyelet loop in it to hold the lead.

author: grenert
author_rank: Frequent Contributor
timestamp: February 27, 2013, 04:10:36 pm
content: You're going to think this is crazy, but...http://www.beadalon.com/BaseCrimpTubes.asp

author: grumpydoc
author_rank: Super Contributor
timestamp: February 27, 2013, 04:23:05 pm
content: Mike (mikeselectricstuff ) has a page on pcb making in which he references a couple of affordable solutions to creating through hole links.
Fluke 87 Display Repair - Page 1
Forum section: electronics / repair

author: Mikey0725
author_rank: Newbie
timestamp: December 30, 2012, 09:59:27 pm
content: I have a 20+ year old Fluke 87 with the very common problem of faded/missing segments in the display. I've had it apart several times, cleaned up the PCB contacts and the elastomer connector strips and treated them with Stabilant-22. Each time upon re-assembly it looks as if things are now perfect again, but within a very short time it's back to where it was, or worse.I'm guessing that the elastomer strips have simply taken a "set" over the course of two decades and need to be replaced. Does anyone know if these are available from Fluke or an aftermarket source? Thanks for your help!

author: retiredcaps
author_rank: Super Contributor
timestamp: December 30, 2012, 10:07:03 pm
content: I have only "fixed" one using IPA.If you want/need a new one, they are sold on ebay. Search for "fluke 87 fading"

author: Mikey0725
author_rank: Newbie
timestamp: December 30, 2012, 10:49:25 pm
content: Just hit eBay, found two sellers with the kits and ordered one, should have it by Friday so the trusty old 87 should be back in action by the weekend. Thanks for the tip!

author: Spawn
author_rank: Frequent Contributor
timestamp: January 19, 2013, 10:14:42 pm
content: Sorry to bring up 20 days old topic, but how did it work for you?I got a 87 suffering with same problem.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 19, 2013, 11:10:29 pm
content: Quote from: Spawn on January 19, 2013, 10:14:42 pmI assume you have tried cleaning it with IPA, but the problem reoccurs within a few weeks?

author: Spawn
author_rank: Frequent Contributor
timestamp: January 20, 2013, 12:17:25 am
content: Not the 87 but one of my 85's and indeed it is coming back on that one, got the 87 recently.EDIT: Well I thought I give Kontakt 60 a go on 87, it is for bigger contacts like big relays and such but it cleans and make the contact work better if you leave a thin lay on it. It seems to work, let’s see how long.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 23, 2013, 08:04:29 am
content: I haven't tried this myself, but someone mentioned a hot water tip for a Beckman multimeter. I don't know if it applies to a Fluke zebra strip or not?http://www.badcaps.net/forum/showthread.php?t=25737

author: Spawn
author_rank: Frequent Contributor
timestamp: January 23, 2013, 08:11:09 am
content: Nice tip thanks, I will wait to see what Kontakt 60 does, if it comes back I will try that one.It was only 3 days ago so I have to wait couple weeks more but till now it's looking good.