hybridfree/eevblog-posts huggingface dataset:
Instek FG-8016G Repair - Anyone got Schematics? - Page 1
Forum section: electronics / repair

author: peterrash
author_rank: Contributor
timestamp: September 27, 2014, 06:24:10 am
content: I've been a long-time viewer of the blog over on Youtube, and I've finally gotten around to joining these forums. I'm hoping someone on here can point me to some info:I picked up an Instek FG-8016G Function Generator on eBay for $35, but it needs some repairs. It powers on ok, but I think somebody has had a go at modifying or repairing it, as there are a couple of missing controls below the display, plus a pair of trimmer pots glued together and floating around loose in the case. I haven't had any luck searching for repair manuals or schematics for this thing, and I was hoping that someone might point me in the right direction, as it's not obvious what all the missing stuff was connected to. I realize that this is not a great function gen, but I don't need much, and for 35 bucks I'd like to get this thing working again.Any help is greatly appreciated.Thanks.-Peter

author: mij59
author_rank: Frequent Contributor
timestamp: September 27, 2014, 06:44:31 am
content: Hi,You can download the manual herehttp://elektrotanya.com/gw_gfg-8016g_digital-function-generator.djvu/download.htmland convert it online to pdf.The pdf file is about 11 MB.Please post some pictures.

author: peterrash
author_rank: Contributor
timestamp: September 27, 2014, 02:42:56 pm
content: Thanks for that link, it looks like there is some good info there. I'll have a go at repairing this thing later today, and I'll try to post some pictures too.-Peter

author: peterrash
author_rank: Contributor
timestamp: September 28, 2014, 03:46:43 am
content: I think the linked manual is for a newer revision or something, but the major features seem to be the same - hopefully that's enough.On closer inspection, it seems that someone has modified this function gen so that there are two extra frequency controls besides the main control knob (the two trimmer pots), and then they've got a rotary switch to select between the 3 controls. I assume this was done to allow toggling between a couple of presets for repetitive tests. I'll add a couple pictures of the mod to this post.I think I'll just cut out the mods and put the controls back to the factory setup with a single knob. I've also discovered that the display doesn't work properly, so I guess I'll be spending some time troubleshooting that next.Thanks again for the info.-Peter

author: dramoto
author_rank: Contributor
timestamp: November 01, 2014, 08:32:00 pm
content: sorry.....Peterrash..... had you find more Instek doumentation? any wiring or service manual?I´m now with a GFG-8019G with some functions to fix. And not lucky yet looking for documentation.

author: peterrash
author_rank: Contributor
timestamp: January 08, 2015, 05:37:02 am
content: Whoops, sorry I didn't reply for so long... Unfortunately I never found any decent schematics or service manual for this model. I ended up just poking around until I figured out how to fix it, and it turned out to be an easy fix. Sorry I can't be of much help to you, dramoto.
Toshiba 46ZF355D - Dead - Page 1
Forum section: electronics / repair

author: urbis
author_rank: Unknown
timestamp: January 07, 2015, 10:17:42 am
content: Hello,I bought this TV as faulty, apparently not powering up.I've not yet tried it, but took the back off, nothing seems visibly failed.However, the one thing that amazed me was the sheer build quality of the thing - not only does it weigh around 17 metric tonnes (OK, perhaps slightly less), but seems built to a high standard.Dedicated audio amp board, decent sized speakers, Rubycon main caps.Some (poor) images below:Obviously, the first thing is going to be to clean everything up and start metering, but has anyone seen failures on this PSU before?Cheers!

author: tautech
author_rank: Super Contributor
timestamp: January 07, 2015, 10:48:31 am
content: QuoteThat doesn't give us much to run with.Standby light?Standby PSU running?LCD backlight failed?Any Audio?If your nervous about plugging it in make a dim bulb tester with a bulb watt rating about the same or a bit more than the TV's rated wattage.That'll allow you to power it without it going bang.

author: urbis
author_rank: Unknown
timestamp: January 07, 2015, 10:59:50 am
content: How does the dim bulb tester work?Cheers!

author: VK5RC
author_rank: Unknown
timestamp: January 07, 2015, 11:12:54 am
content: If I am correct, you put an incandescent bulb in series with the mains input, the increasing resistance of the bulb as it takes more current means if the device is a dead short (and the bulb lights up) you won't blow too much stuff up!If the device under test is ok the light bulb goes out.

author: tautech
author_rank: Super Contributor
timestamp: January 07, 2015, 11:18:07 am
content: Quote from: VK5RC on January 07, 2015, 11:12:54 amNearly right.If the DUT is OK the bulb will glow dim.Do some tests on working appliances to get a "feel" for it.Google Dim Bulb Tester.
AWG-2005 function generator output voltage - Page 1
Forum section: electronics / repair

author: Rachie5272
author_rank: Regular Contributor
timestamp: January 12, 2015, 10:59:52 pm
content: I have a Gw Instek AWG-2005 arbitrary function generator with a strange problem. For the most part it works properly, except in the 0.2-0.6 Vpp output range. It will output a signal above and below this range, but drops to zero in between. Interestingly, this range corresponds with a relay click.By probing around with a scope, the signal seems to disappear in the relay which clicks in this range. I can't figure out why though. Testing the relay with a multimeter gives expected continuity readings, and the only nearby components are SMD resistors, capacitors, and the back EMF diodes. Not the sort of parts which typically go bad.The relay in question is RL302, on the right of the group of three relays. TP106 to the right of this seems to be the signal before attenuation. The resistors below the relays seem to be the signal attenuators.Any suggestions on what to try next? Pull off the relay?

author: Rachie5272
author_rank: Regular Contributor
timestamp: January 15, 2015, 11:35:40 pm
content: I think I found the problem, but it creates more questions than answers.I was probing around looking for clues, when I decided to check the resistors. Both R309 and R311 read completely open. I reflowed the joints, and made sure to jab my probes well into the solder bead, but still nothing. All the other resistors read close to their stamped values (accounting for in circuit networks). The resistors in question are labelled "93R1" and "82R5", which should be 93.1 and 82.5 ohms.My theory is someone shorted the function generator output to a voltage rail, which caused a large current to flow through these resistors, burning them out. It's a rather bad design if this is the case. The BK Precision function generator I have at least put a fuse on the main output.Now for the hard part: buying two SMD resistors without paying 1000 times their value in shipping.

author: alex.forencich
author_rank: Frequent Contributor
timestamp: January 17, 2015, 05:55:42 am
content: What about picking up an SMD resistor kit? There are a few on ebay for ~$40 or so IIRC that have a gigantic range of values. Might come in handy for other projects as well. Otherwise, it might be advisable to wait until you have to order a few other things so you can amortize the shipping cost.

author: saturation
author_rank: Super Contributor
timestamp: January 17, 2015, 03:28:27 pm
content: Good job finding the fault. Resistors failed open without signs of failure is odd. Nevertheless failing open is good as you can carefully clip a known working resistor atop the failed part and insure the unit now works as specified.Methinks whatever the cost of these resistors is far less than buy a new AWG 2005.You could add the output fuse yourself and thus prevent a future failure. IMHO many FG I encounter have limited output protection and no fuses, so as rule I assume all FG are similar.http://cp.literature.agilent.com/litweb/pdf/5989-8790EN.pdf
Trying to repair my old Motorola Xoom. - Page 1
Forum section: electronics / repair

author: Asavage9794
author_rank: Contributor
timestamp: January 06, 2015, 05:34:36 am
content: About 3 months ago I noticed the screen on my tablet was completely dead. So i went inside a chip had went up in magic smoke but i have no idea what kind of chip it is, I want to buy a replacement chip to put in it so it can work again. Everything works besides the screen and i can plug it into HDMI.

author: Stonent
author_rank: Super Contributor
timestamp: January 06, 2015, 06:43:14 am
content: Quote from: Asavage9794 on January 06, 2015, 05:34:36 amCan't read it.

author: Asavage9794
author_rank: Contributor
timestamp: January 06, 2015, 07:09:48 am
content: I can read it ether. Thats the issue lol. I was wondering if any of you had a motorola xoom so one of you can read it to me. that chip inside mine was completely burnt and now its long gone cause i removed it unfortunely.

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: January 06, 2015, 01:52:13 pm
content: I see "(triangle)AY" across the front, and "V8" across the side in that picture. Google doesn't get me anywhere though.

author: Stonent
author_rank: Super Contributor
timestamp: January 06, 2015, 03:41:57 pm
content: Quote from: Asavage9794 on January 06, 2015, 07:09:48 amWell you have it in front of you and we have a blurry small picture. Can you get a better picture maybe with macro mode and a bright light overhead?

author: Asavage9794
author_rank: Contributor
timestamp: January 06, 2015, 06:40:25 pm
content: I pulled that picture off google. the one in the real tablet is completely gone lol.

author: Asavage9794
author_rank: Contributor
timestamp: January 06, 2015, 08:48:51 pm
content: I got a idea. Ill edit the photo and see if theres a way to see it better.
[solved] Expert Help needed to find the right package [FS-R9B] - Page 1
Forum section: electronics / repair

author: Dani203
author_rank: Newbie
timestamp: December 31, 2014, 04:30:40 pm
content: Hi EEVBlog Community,Today i recieved my RC-Reciever and accidently connected it directly to the 11,1V Lipo instead of a 5V Power Supply, which burned out a 4 Pin Package on the PCB, i believe it is a Linear Voltage Regulator...i have some experience with soldering and i think i could exchange that component with ease, but i am not entirely shure what kind of package that is and where to get it...I Messured it to be 4.5mm X 2.5mm. Since the reciever is meant for 4.5V - 6.5V i assume it is a 3.3V LDO i destroyed there...Any help with finding the right component would be super appriciated, since i want to (at least try to) reciver that reciever to fly my Quadcopter with it...Thats in advance!

author: helius
author_rank: Super Contributor
timestamp: January 01, 2015, 02:57:34 am
content: SOT-223

author: Dani203
author_rank: Newbie
timestamp: January 02, 2015, 10:12:30 pm
content: Well, a SOT-223 is too big, but thanks to your tip i found out that it was a SOT-89. Tried soldering in another one which did not bring life back into it, but well, atleast i tried, thank you!

author: elerepair
author_rank: Newbie
timestamp: January 05, 2015, 12:50:08 pm
content: You know, that just by matching package, is not going to fix anything? get the number from the package, and google the datasheet. then get the same or analog part.Re: dont know if links are allowed. quick google search -- by receiver model. Then switch to pics.http://www.rcgroups.com/forums/showthread.php?t=1949373

author: Dani203
author_rank: Newbie
timestamp: January 06, 2015, 07:09:08 pm
content: I know that finding the right package is not a garantee, but i could not imagine it being something other than i 3.3v regulator (for given reasons). by now i already have a workling replacement reciever, so there is no real need to repair it...also it looks like i took out the really tiny capacitor right next to the SOT-89 accidently, and i don'r really know its specs, so its kinda lost anyways i think...
Repairing Triumph Triple 900 Gill ECU/Ignitor - Component identification - Page 1
Forum section: electronics / repair

author: lukejjames
author_rank: Newbie
timestamp: January 12, 2015, 08:00:51 am
content: Hi Eevblog Community,Long time reader, first try at a repair. So be kind if I don't use correct termsMake a long story short I have been working on getting a 1998 Triumph 900 running and had no spark on one of the three coils. Determined it was not the coil by switching the leads of the working coil with the one that was not working and it sparked! So I opened the unit and started to probe. The coils are wired to +12 and to the collector on the tip152s; one for each coil. The signal on the base of the of the tip152 (TR11) wired to the non sparking coil was very weak when compaired with the signal on the other two, so I swap the driving transistors TR3 and TR4 with TR8 and TR7. Yay it worked! now the non-working coil was firing! but of course TR9 was failing.. So I need to order a replacements for TR4 and TR3. The problem is I can't seem to identify replacementsIm guessing TR stands for transistorI attached two images one of the whole board and one of the two SOT-23's im trying to identify. But have not had much luck on google. Any assistance would be great.. Im pretty sure they are npn transistors but would like a second opinionSOT-23?MarkingsTR4 - G6B (44?)TR5 - C6I goofed on the pic - shows TR5 and TR6..

author: carpelux
author_rank: Regular Contributor
timestamp: January 12, 2015, 11:53:34 am
content: if You look at theGM4PMK's SMD CodebookG6B = BC817-25 (leaded BC337-25) and C6 =MMBA811C6 (leaded 2N5086)

author: lukejjames
author_rank: Newbie
timestamp: January 13, 2015, 11:02:40 pm
content: Hey Thanks carpexStill having a bit of a hard time finding replacements..Does it have to be a pnp EPITAXAL transistor ("a bipolar junction transistor made using vapor phase deposition")or will any pnp bipolar junction transistor within the same spec work?thanks again

author: wagon
author_rank: Frequent Contributor
timestamp: January 15, 2015, 08:39:39 pm
content: I reckon if the specs are about the same it should work. I myself fixed one of those a while back ; it had a dead channel too, but it had a dead coil driver transistor.
Quick Samsung PSU Capacitor Question... - Page 1
Forum section: electronics / repair

author: urbis
author_rank: Unknown
timestamp: January 01, 2015, 06:36:40 pm
content: Hello,I'm looking at a friend's Samsung TV with bulging caps, however, as seen on the picture below, the two on the right hand side are 820uF, which seems to be awkward to find:Looking at the bottom of the board, they seem to be wired in parallel, therefore, my question is which would be best:1x 1000uF Cap replacing one, and a 680uF cap replacing the other.Or2x 1000uF CapsCheers!

author: tautech
author_rank: Super Contributor
timestamp: January 01, 2015, 06:51:26 pm
content: As they are straight after the rectifier diodes and subject to a good amount of ripple, I would select good quality Low ESR, high ripple 1000 uF replacements.If physical size of diameter looks tight, get taller if you have the clearance.Check there is sufficent voltage headroom also, manufacturers run caps too close to their rated voltage IMO.We do ourselves no favors by skimping on a repair of this type.Get some extras.....you will use them.

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: January 01, 2015, 08:50:08 pm
content: I would go with 2 1000uf caps, they're a common value, so they're easy to stock up on.

author: urbis
author_rank: Unknown
timestamp: January 01, 2015, 08:59:35 pm
content: Had a couple of 1000uF caps lying around, now up and running.Cheers guys.

author: tom66
author_rank: Super Contributor
timestamp: January 01, 2015, 10:11:21 pm
content: Just a note with these Sammy's, replace every single capacitor on the secondary. They are all bound to fail sooner or later.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 02, 2015, 02:56:55 am
content: More is almost always better. The only reason it might not be, is if it screws with the power supply controller's response time (and it breaks into oscillation or something bad like that).For the same reason, high performance, low ESR caps may not be ideal, either -- these sorts of circuits are a triumph not only of engineering to a cost, but to a time as well!Tim

author: Yago
author_rank: Frequent Contributor
timestamp: January 02, 2015, 12:25:37 pm
content: Quote from: T3sl4co1l on January 02, 2015, 02:56:55 amIs that a case of searching for the ESR specs of mystery caps, or is there a rule of thumb?

author: tom66
author_rank: Super Contributor
timestamp: January 02, 2015, 04:10:37 pm
content: I have always used Panasonic FC/FM/FR as they are good midrange caps and never had an issue, probably 20 PSUs recapped now, if not more, all worked first time (when the caps were the fault)
please help!! yamaha htr - 3066 receiver no sound - Page 1
Forum section: electronics / repair

author: Jesse
author_rank: Newbie
timestamp: January 02, 2015, 12:48:05 am
content: Hi all I am new here im really hoping someone can help, in short system was working fine but my brother tried to update the firmware via usb but it was for the wrong model and apparently it didn't finnish the update a button was pressed and the system turned off now I have no speaker channels. If any more info is needed please let me know thanks guys

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: January 02, 2015, 01:44:58 am
content: If it's anything like a phone, couldn't you just flash it again with the right model's firmware? Unless it's bricked, then you're probably going to have to open it and look for a JTAG footprint.

author: miguelvp
author_rank: Super Contributor
timestamp: January 02, 2015, 02:09:50 am
content: Manual:http://download.yamaha.com/api/asset/file/?language=en&site=usa.yamaha.com&asset_id=58782page 66 Updating the firmwareBut you probably will have to ask them for the firmware because it's not on their download site.http://usa.yamaha.com/support/contact/

author: Jesse
author_rank: Newbie
timestamp: January 02, 2015, 09:22:42 am
content: Thanks much appreciated id say you couldn't brick an amp and yes my thoughts are on the same path as you if I can get the original firmware im assuming that will pretty much restore to factory ill contact yamaha for the firmware and keep you posted.
repair - Page 1
Forum section: electronics / repair

author: Akashthakur
author_rank: Newbie
timestamp: December 31, 2014, 06:35:52 pm
content: please answeer

author: tom66
author_rank: Super Contributor
timestamp: December 31, 2014, 06:42:12 pm
content: If solder is melting, hot glue and tape will definitely melt!Or do you mean, the solder does not adhere? Because you can't solder to all surfaces.

author: lewis
author_rank: Frequent Contributor
timestamp: December 31, 2014, 06:44:52 pm
content: Crimps or a ferrule

author: HighVoltage
author_rank: Super Contributor
timestamp: January 01, 2015, 11:17:18 am
content: In the USA I have seen plumbers use something called JB-Weld, an adhesive that works on metal pipes and I was surprised that they could plug a bad pipe ate least temporary.

author: Simon
author_rank: Unknown
timestamp: January 01, 2015, 09:25:11 pm
content: I have locked this topic as it makes no sense whatsoever. My guess would be that it is potentially an attempt at spam or that the original poster has such poor English that he is not formulated a question which makes any sense whatsoever.
ceramic resistor abbreviations - Page 1
Forum section: electronics / repair

author: jbomba
author_rank: Contributor
timestamp: December 30, 2014, 07:51:42 am
content: hi guys bit new to repairing pcbs. anyway ive got a ceramic resistor on a pcb that has spewed its guts on the pcb. Red crap everywhere. the abbreviation on the resistor is 5w22KRK. would i be correct to assume this is just 22k or does the rk afterwards mean something different?

author: Christopher
author_rank: Frequent Contributor
timestamp: December 30, 2014, 08:05:16 am
content: Yes replace it with a 5w rated 22k resistor, you are right. The RK is probably gonna be tolerance information.

author: Derresh
author_rank: Contributor
timestamp: January 01, 2015, 10:22:11 am
content: R is the Multiplier Info, in this case its R means x1, dunno why they put both K for x1000 and R there... but well maybe they wanted to make it clear its a Resistorthe last K is indeed tolerance, stands for 10%
Help with connector ID - Page 1
Forum section: electronics / repair

author: hns0
author_rank: Newbie
timestamp: January 02, 2015, 02:16:07 am
content: Hello,I was wondering if anyone could help me identify the wire-to-board connectors used on this board (attached photo), highlighted in orange. They are approximately 100mil in pitch. If anyone knows the manufacturer/product line, it would be much appreciated.Thanks,Henry

author: andtfoot
author_rank: Unknown
timestamp: January 02, 2015, 08:48:56 am
content: Looks like shrouded Molex SPOX headers to me:http://www.molex.com/molex/products/datasheet.jsp?part=active/0022035025_PCB_HEADERS.xml

author: hns0
author_rank: Newbie
timestamp: January 02, 2015, 06:35:39 pm
content: That looks exactly right - thanks!
agilent U1602B - Page 1
Forum section: electronics / repair

author: p-p-a
author_rank: Newbie
timestamp: December 30, 2014, 10:28:07 am
content: Hello. I bought an oscilloscope Agilent U1602B and attempted to update to 1.1.5 firware update file and wrong bin. The program was interrupted while deleting your bug report. Unbinding the battery does not help only comes on a gray screen on the oscilloscope and the lack of communication with the computer. The program update does not connect to the oscilloscope. Help.

author: lowimpedance
author_rank: Super Contributor
timestamp: December 30, 2014, 11:42:28 pm
content: The U1602b is still current, Talk to Keysight.
Poor program, need to reset MCU daily for solar light to function properly - Page 1
Forum section: electronics / repair

author: notzippy
author_rank: Regular Contributor
timestamp: December 29, 2014, 09:05:20 pm
content: Hi,I have a solar powered light that is supposed to switch off after 4 hours,6 hours, or all night after turning on at night, but the unit only functions properly (using the 4,6hr timers) on the first night, every night after (the first) it turns on and stays on until morning (or the batteries run out). The circuit revolves around an unmarked 8pin IC (I assume it is a programmable IC) three of the pins are inputs to the switch, one detects if the solar panel is collecting power and the last drives a couple of transistors to turn the leds on.What I would like to do is briefly interrupt power to the ic after the unit turns off the leds, this should simulate someone turning the switch off and on. So my thought is to power the ic using an inverted monostable multivibrator arrangement. Does anyone have a good example on how to do this with transistors ? I need the output to be normally high and dropped temporarily to a low (triggered by a high to low transition). Or would a better solution would be to replace the badly programmed ic with my own ? I am not sure what the cheaper solution would be.The solar led's were $40 for each and currently all 9 they have operate with the same issue. The manufacturer claims he will fix the problem in the future but has not offered any solution to fix the current units.ThanksNz

author: notzippy
author_rank: Regular Contributor
timestamp: December 30, 2014, 03:50:13 am
content: 99% sure the controller is a picaxe, if that is the case it will be a simple matter to program it properly.. Waiting for programming cord..nz
Repair of Garmin Nuvi 50 - Battery Charging Issue - Page 1
Forum section: electronics / repair

author: luis.v
author_rank: Newbie
timestamp: December 27, 2014, 04:15:40 am
content: Hi! I tried to repair this nuvi 50 GPS for a friend of mine. At first, I tought it was just a simple battery replacement, but seems to be the battery charging circuit on the main board, because it works with USB power on, it works with another full-charged battery connected to the board but doesn't work with the discharged battery (the original battery was tested and is OK, it was only discharged) until connected to the USB Power which the charging icon appears but doesn´t charge the battery. I need help identifying the two semiconductor components near the battery connector, the transistor like 052R3 and the HDW 2SAA which I think are involved with the battery charging. Voltage Readings without battery are1- 0V2- 0V3- 0V4- 5.25V5 - 4.4VWith Battery ON1- 3.7V2- 3.7V3- 3.7V4- 5.25V5- 4.4VSomething is not switching, anyway, thanks for the replies!!

author: Zepnat
author_rank: Regular Contributor
timestamp: December 27, 2014, 05:00:52 pm
content: If it works with a new battery but not the original surely the battery is simply worn outEdit. Does it charge the new battery?

author: luis.v
author_rank: Newbie
timestamp: December 27, 2014, 05:18:12 pm
content: Hi!, no it doesn't. That's why I suspect the charging circuit is failing. I believe that 4.4V spot over there its the battery charging voltage, but I'm not for sure.

author: tautech
author_rank: Super Contributor
timestamp: December 27, 2014, 06:47:25 pm
content: Take a look at BZX84 series Voltage regulator diodes for the SOT-23.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 28, 2014, 04:17:49 am
content: You can add your own charging circuit. I suggest looking at simple one chip solutions.Another possible cause is the OEM making the charging circuit check for an OEM charger as a way to prevent third party chargers from working.

author: amyk
author_rank: Super Contributor
timestamp: December 28, 2014, 03:57:10 pm
content: HD W is a VishaySiA811ADJ052R3 isprobably a Vishaybut I can't be bothered looking through all their SOT-23s.
Panasonic WV-3030e, Wont display colours correctly. - Page 1
Forum section: electronics / repair

author: Boyfinn
author_rank: Newbie
timestamp: December 30, 2014, 07:22:53 pm
content: Sorry for heavy image size!So, I recently picked up a Panasonic WV-3030e camcorder for a really good price.As far as i know all the features work fine except for the colors.Sometimes when the camera is turned on, the colours show up for a little while, And after about 10-20 seconds the colours fade out and im left with a black-and-white image.Here's a picture with the colours still working:I've already checked the insides and i see no visible damage on any of the boards or components.My firend suggested me that it might be a problem with the capacitors but i cant see any visible damage or bulging on the capacitors.If anyone here has experience on vintage colour cameras i really would appreciate the help. I have multiple detailed pictures of all the boards which i can upload if necessary.Also if anyone has access to the schematics of this thing i would love to see them. And if you have an idea about what this camcorder is worth please let me know. Because if its not that valuable i would like to salvage the viewfinder from it (which is probably the smallest colour CRT i've ever seen).

author: tom66
author_rank: Super Contributor
timestamp: December 30, 2014, 10:08:43 pm
content: Could be a defective colour-burst crystal drifting? Perhaps try heating/cooling/tapping the crystal.
Rewind and Repair of Large Toroidal Transformer - Page 1
Forum section: electronics / repair

author: SgtRock
author_rank: Unknown
timestamp: December 25, 2014, 07:50:21 am
content: Greetings EEVBees:--I just came across this fellow "feedbackloop". In the attached video he unwinds, repairs, and then rewinds the main toroidal transformer, and fixes an Array 3664A bench power supply. Now it did take a bit of work, but nothing difficult. If you happen to have a similar power supply, or even an expensive audio amplifier, with a toroidal main transformer, this technique could save you a ton of money, an allow you to keep a valuable piece of equipment rather than trashing it. I hope this will be of help to someone."I believe that at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted."Alan Turing 1912 - 1954Best RegardsClear Ether

author: SeanB
author_rank: Super Contributor
timestamp: December 25, 2014, 08:16:48 am
content: I have rewound transformers and motors, and it is doable, if somewhat fiddly. Have never done toroids other than making current transformers out of them.At least in the video a secondary side short is easy to get at, though you will need a lot of tape to rewind it if you are going to do so. Myself if it is a secondary short and it has those insulating washers just leaving bare is how it will be.
LCD Repair - Page 1
Forum section: electronics / repair

author: dimitris1989
author_rank: Newbie
timestamp: December 24, 2014, 08:42:19 am
content: Hello all,I have a Samsung T200 LCD monitor, and some time ago it started showing a white screen. At first it would recover after a few power offs and ons but now it's always white.I opened it up, checked for bad capacitors on the power board but everything is fine. Is there anything else I can check or it's beyond repair?Thank you

author: wraper
author_rank: Unknown
timestamp: December 24, 2014, 12:26:44 pm
content: Try to reseat LCD cable connectors, move the cable, press with finger BGA chips and power on while holding.

author: dimitris1989
author_rank: Newbie
timestamp: December 24, 2014, 03:19:42 pm
content: Quote from: wraper on December 24, 2014, 12:26:44 pmThank you for your replyI tried it, but it didn't work

author: AKM
author_rank: Contributor
timestamp: December 24, 2014, 05:53:57 pm
content: TN panels usually work in normally white mode (it forms the picture by blocking unwanted colors from the backlight), so when you have a white screen on a monitor with TN panel, it is the panel which doesn`t work. Try checking the T-Con board for the voltages it needs to work(usually 5V); if there is a SMD fuse on the T-Con board, check it too; if the fuse is blown, check for shorted components before replacing it with an equivalent fuse(take care to notice components in parallel, especially the bypass capacitors).
What can introduce very high latency inside the broken Fast Ethernet controller? - Page 1
Forum section: electronics / repair

author: m4rtin
author_rank: Regular Contributor
timestamp: December 22, 2014, 08:45:30 pm
content: I have a fairly old 10BASE-T/100BASE-TX NIC for PCI bus with RealtekRTL8139Dchip:At first I had very high(up to 2000ms) latency with this NIC even to hosts in my local area network(latency should be <1ms). In addition, packet delay variation was very high fluctuating from 20-30ms to 2000ms. Now if I load the driver:Code:router:~# modprobe -v 8139tooinsmod /lib/modules/3.2.0-4-686-pae/kernel/drivers/net/ethernet/realtek/8139too.korouter:~#..the card does not respond at all:Code:[ 131.363894] 8139too 0000:00:0d.0: Chip not responding, ignoring board[ 131.363992] 8139too: probe of 0000:00:0d.0 failed with error -5Other Network Interface Cards in the very same PCI slot work just fine. Looks like theRTL8139DFast Ethernet controller is faulty. I am curious what happens inside the chip if it is half-broken and introduces such high latency? I understand that this would require exact schematics of the chip(obviously proprietary), but an educated guess from someone who has experience with chip design is also fine

author: wraper
author_rank: Unknown
timestamp: December 22, 2014, 08:50:06 pm
content: Probably crystal oscillator frequency is off or data in 93C46 is corrupted.

author: mazurov
author_rank: Frequent Contributor
timestamp: December 22, 2014, 11:11:44 pm
content: Try to turn off auto-negotiation on both sides of the link.

author: Shock
author_rank: Super Contributor
timestamp: December 23, 2014, 02:49:27 pm
content: Clean the jack and slot pins with alcohol and a cotton bud etc.Use a loop back connector when testing unless you like wasting time.Don't use an OS use something like the vendors floppy diags or if your low on options a generic one.You might be right and it's faulty but if you didn't know the above or things like how ATX power and interrupts work then likely your jumping to the wrong conclusion.

author: janoc
author_rank: Super Contributor
timestamp: December 23, 2014, 02:58:33 pm
content: Just bin it. These Realtek chipsets are known for their bugs and problems - google "8139too" and see for yourself. They are used because they are dirt cheap, but often require some dirty driver hacks working around problems with the silicon itself.

author: rob77
author_rank: Super Contributor
timestamp: December 23, 2014, 03:58:39 pm
content: Quotei would bet on the PCI connector contactsthat log message tells you the probe of PCI device failed. if cleaning the connector doesn't help then desolder the usable parts (crystal, LDO, eeprom, that 1Kv ceramic cap, ferrite beads) and trash the rest
sony str-av900 - Page 1
Forum section: electronics / repair

author: daine22
author_rank: Newbie
timestamp: December 20, 2014, 09:58:17 am
content: hello guys,what diode can i use to replace US1060M on my Sony STR-AV900 FM/AM Stereo Recieverhttp://www.datasheetarchive.com/dlmain/Databooks-5/Document290-10324.pdfTYIA

author: tautech
author_rank: Super Contributor
timestamp: December 20, 2014, 09:52:43 pm
content: Welcome to the forum.By your posted link, one would assume it is in a power path not a signal path.If this is the case, it is likely it's spec's are not critical unless in a SMPS.Go to one of the big component suppliers websites and apply the filters for selection to match your requirements.http://nz.rs-online.com/web/c/semiconductors/discrete-semiconductors/rectifier-schottky-diodes/

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 20, 2014, 10:02:48 pm
content: We can guess from that Japanese spec page, but it would be extraordinarily helpful to see the schematic diagram of where the diode is being used in the circuit.

author: daine22
author_rank: Newbie
timestamp: December 21, 2014, 08:26:30 am
content: thanks guys for the reply! the diode is on control computer IC, can i replace it with 1N4148 diode?TYIA

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 21, 2014, 01:40:14 pm
content: It makes one wonder how it failed open?And how you discovered the problem?And whether the battery needs replacing also.
Looking for FET to replace UTD405L for toy tractor - Page 1
Forum section: electronics / repair

author: xnaron
author_rank: Contributor
timestamp: December 19, 2014, 09:22:25 pm
content: I am helping a friend repair a remote control toy tractor. The motor was burned out and we replaced that. When we tested it was apparent by magic smoke that a FET was blown. The markings on it are :UTCUTD405L57OHCQThis looks to be the devicehttp://pdf1.alldatasheet.com/datasheet-pdf/view/454611/UTC/UTD405L-TN3-R.htmlI have tried to find a replacement for it unsuccessfully. Would anyone here be able to suggest a suitable alternative?I am attaching a picture of it as well.thanks

author: wraper
author_rank: Unknown
timestamp: December 19, 2014, 11:02:36 pm
content: Anything P-channel in TO-252, >30V Drain-Source Voltage , RSDon <40 milliohm, >18A Continuous Drain Current and gate capacitance being lower to slightly obove 1nF (probably won't matter if there is no PWM).For example these would do:http://lv.farnell.com/advanced-power-electronics-corp/ap4435gh-hf-3tr/mosfet-pch-30v-20mohm-to-252/dp/2319617http://lv.farnell.com/fairchild-semiconductor/fdd4685/mosfet-p-ch-40v-32a-to-252/dp/2323171

author: xnaron
author_rank: Contributor
timestamp: December 19, 2014, 11:40:42 pm
content: Thank you very much Wraper. I will give it a try.
Chips on PCB of Bosch pump VP44? - Page 1
Forum section: electronics / repair

author: dds737
author_rank: Contributor
timestamp: December 17, 2014, 12:31:15 pm
content: Can somebody identify these? It's almost impossible to identify producer :-/Thanks!

author: Andreas
author_rank: Super Contributor
timestamp: December 17, 2014, 08:43:52 pm
content: Quote from: dds737 on December 17, 2014, 12:31:15 pmHello,seem to be customer specific produced parts.The maximum you can try is to identify them by function.But this is only possible if one knows the surroundings.The 8 pin could be one of: CAN-driver, current measurement amplifier ...so are they near a shunt resistor (perhaps on the other side), or common mode CAN choke?The 14 pin could be perhaps analog multiplexers, LM290x OPAmps/Comparators, or discrete logic.With best regardsAndreas

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 17, 2014, 09:03:19 pm
content: Unless you can find good documentation for the Bosch VP44 unit, finding any information about OEM house-number components is practically impossible.You did not reveal WHY you want identify these chips. If you are thinking that you can somehow repair or modify that board without good documentation, you may be dreaming.And even if you COULD identify the chips AND you could obtain good documentation, the chips may very well be custom-made, presenting yet another dead-end.

author: dds737
author_rank: Contributor
timestamp: December 17, 2014, 10:43:54 pm
content: Quote from: Richard Crowley on December 17, 2014, 09:03:19 pmWell, originally it was discussion on one Serbian forum about VP 44 board repair last year, and I mentally touched subject again and posted question for help here. I see your point, this is tough nut to crack, if not impossible with limited resources (no docs, probably custom made chips)

author: amyk
author_rank: Super Contributor
timestamp: December 18, 2014, 01:05:41 am
content: Tracing the schematic would help greatly in identifying their function.The font on the first set looks like they're made by Philips/NXP.

author: wagon
author_rank: Frequent Contributor
timestamp: December 19, 2014, 10:33:26 pm
content: Bosch do some weird stuff.... once I reverse-engineered and then replaced (with common parts) a chip in an engine controller for a ride-on lawnmower engine. It has two or three low-side drivers and a 5 volt regulator in it. I don't recall seeing anything like that in other products.
Universal programmer VPP Actual VPP Voltage vs Rated 25v - TOP853 - Page 1
Forum section: electronics / repair

author: weirdaljr
author_rank: Contributor
timestamp: December 19, 2014, 03:43:14 pm
content: Hello,I wanted to see what you thought about this, and see if anyone has one to verify my finds. I have a TOP853 eprom programmer (among others, this is a cheaper one) that is rated for 25v chips, and had 100s of them in its list. For the example I will say a 2716-25v. After noticed my programmer has a lot of problem programming these I probed the programming pin (VPP Pin 21 on the 2716) voltage while programming and found it to be only at ~20.5v while programming. First thinking it was due to it using the USB bus power I tried again with a USB powered hub and it got to 20.7v. Now I know some 25v chips may program at 21v but not all, but I was more concerned with why the programmer was not outputting the correct voltage. Next I opened it up as I was told it had unused connections on the board for a external power supply, and their was. I connected that to my variable supply and started at 5v and tried up to 5.6v (didnt want to go higher not knowing if the circuit could handle it) and that got the programming vpp up to 20.8v trying to program a 25v chip. For a comparison I tried testing it on a 21v chip and the voltage is the same (20.6-20.8v depending on power source).My question is this. Is this programmer defective (it does program most chips >25v) ? Or is this the way it was designed claiming it can program 25v chips, but actually only supplies them a VPP of 20.7v hoping it works?Can anyone else with a top853 verify theirs only outputs ~20.7v for VPP on when trying to program any 21v & 25v chips?

author: amyk
author_rank: Super Contributor
timestamp: December 19, 2014, 04:07:04 pm
content: You could see what type of circuit it uses to generate the programming voltage, and measure the output voltage with no load; its impedance might be too high to supply enough current at 25V. The 2716s require ~5mA continuous on the 25V rail, with pulses up to 30mA when programming, and nearly 100mA on the 5V.
Thurlby Thandar TSX3510 PSU Repair - Page 1
Forum section: electronics / repair

author: TheBay
author_rank: Unknown
timestamp: November 08, 2014, 05:32:55 pm
content: All,My trusty PSU is having issues, it started when I had something powered up on the bench and went out, came back and the PSU was making a bit of a noise, turned out the device I had on soak test contained a SLA battery (I had no idea there was one inside), which I later found out was dead and assume this has damaged my PSU.This is a Hybrid type SMPS/Linear PSU and not that familiar with the workings of it, what happens is when I put any load on it the CV light flickers on and off and the voltage drops up and down with some whine, seems worse after around 11-12v, with no load the output is accurate as soon as it's loaded up the output voltage drops.Before I whip it apart is anyone familiar with the Thurlby Thandar TSX range? I can post it to TTI for repair but it's not that cheap and might have a go at fixing it myself.

author: TheBay
author_rank: Unknown
timestamp: November 08, 2014, 06:03:47 pm
content: Just a quick video:

author: macboy
author_rank: Super Contributor
timestamp: November 09, 2014, 07:37:25 pm
content: Service manual attached.Due to silly board attachment restrictions, it is in two parts. Remove the .txt extension so that you have a .001 and .002 file. Use 7zip to extract the .001 file.

author: TheBay
author_rank: Unknown
timestamp: November 09, 2014, 08:26:20 pm
content: Quote from: macboy on November 09, 2014, 07:37:25 pmThanks for the files, will have a nose

author: TheBay
author_rank: Unknown
timestamp: December 19, 2014, 10:09:49 am
content: Unit is now working, was 2 LARGE 500uf 200v Capacitors.
What lubrication for Variac/Auto Transformer? - Page 1
Forum section: electronics / repair

author: Shock
author_rank: Super Contributor
timestamp: December 16, 2014, 02:09:33 pm
content: Is there any preferred way to clean and lubricate the windings on a Variac?What do the manufacturers put on, anything?The lubricant would have to be non conductive and safe for around 300v.

author: Andy Watson
author_rank: Super Contributor
timestamp: December 16, 2014, 02:27:02 pm
content: Carbon - i.e. the graphite brush, should be a good-enough lubricant on its own. But the carbon dust is conductive - so keep it clean.

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2014, 02:34:13 pm
content: Clean the top track with some cloth and IPA, and then simply wipe the moving contact back and forth 4 or 5 times then use the dry cloth again to polish off the small amount of black dust. That will keep the track bright and clean. If it is dull and oxidised use a pencil eraser ( the white soft one) to rub gently till shiny. Careful though, this does wear the wire there thinner, so only do it as a last resort.

author: Shock
author_rank: Super Contributor
timestamp: December 17, 2014, 01:57:38 am
content: I measured and it was very intermittent on ohms. I thought about using an eraser but noticed while I was probing it was hard even to scrape any of the build up off.I ended up cleaning it well with IPA first and used some 800 wet and dry sand paper (dry). Took a few wipes got most of it off, then used IPA and a clean rag. I also leveled the brush as it was a pitted.When mounting the brush how much pressure should you apply?

author: Chris Jones
author_rank: Regular Contributor
timestamp: December 17, 2014, 05:25:35 am
content: I used Electrolube EML spray, no trouble so far and I hope it will prevent the copper wire from oxidising. It would be very posh if you could get the contact part of the windings hard gold plated!

author: SeanB
author_rank: Super Contributor
timestamp: December 17, 2014, 08:23:33 pm
content: Quote from: Shock on December 17, 2014, 01:57:38 amDepending on the brush material about 5-30g of force to just lift it off the surface. For really big ones ( brushes that you can use on a truck starter or bigger) 100g or so. for those that handle welding levels of current they tend to have a spiral spring to provide the correct pressure.
Xmas Emergency!!  IC question for tv repair (present)  HELP! - Page 1
Forum section: electronics / repair

author: MtnFrost
author_rank: Newbie
timestamp: December 25, 2014, 01:56:43 am
content: Help!I was repairing a television (Toshiba 37XL96) power supply for a surprise TV present for my wife.The parts dealer sent me the wrong IC - I needed a STRW6765. They sent a STRW6735.Now looking at the stats, the difference is this:the 65 - 800 V / 1.8 ?, 52 to 110 W (Universal/230 Vac input)the 35 - 500 V / 0.57 ?, 160 W (120 Vac input)Now I know enough electronics to make simple circuit board repairs. But this is a little beyond me. Could I use the -35 instead of the -65, since it's just a switch for the power relay?I can't get another part Xmas eve, but if I can use this, please let me know asap! A Christmas gift is depending on it!Thanks!

author: Psi
author_rank: Super Contributor
timestamp: December 25, 2014, 07:14:06 am
content: It looks to be just a voltage/power difference, either universal input or 120V only.Are you in a 230 or 110v country?I've only skimmed the datasheet but if your mains is 120V you can probably use either chip.The STRW6735 can handle more power so that's fine, but its limited to 120V

author: wraper
author_rank: Unknown
timestamp: December 25, 2014, 07:48:30 am
content: Quote from: MtnFrost on December 25, 2014, 01:56:43 amWhat do you mean by power relay switch and -35/-65This is not relay switch but SMPS PWM controller with integrated transformer switch. Likely will work if your country have 110-120V mains voltage. Do not use it if you have 220-240V mains voltage. But check if it is powered directly from mains diode bridge, if there is PFC in between, do not use it.

author: MtnFrost
author_rank: Newbie
timestamp: December 25, 2014, 02:15:38 pm
content: -35 = shorthand for the IC 6735-65 = shorthand for the IC 6765I'm in the US, so 120v.THanks!

author: wraper
author_rank: Unknown
timestamp: December 25, 2014, 08:48:12 pm
content: Quote from: MtnFrost on December 25, 2014, 02:15:38 pmThere is no such parameter in the datasheet. Probably you wrote some dealer imagination.

author: MtnFrost
author_rank: Newbie
timestamp: December 25, 2014, 09:33:22 pm
content: strw6765strw6735
Multipole connector - Page 1
Forum section: electronics / repair

author: wiss
author_rank: Frequent Contributor
timestamp: December 17, 2014, 04:13:37 pm
content: I'm trying to repair the cable for a turbo-pump, one, several, wires have broken close to the connector.How can I open it?

author: 8086
author_rank: Super Contributor
timestamp: December 17, 2014, 04:15:40 pm
content: You need to hold the central part that has the holes in it, and the back part will unscrew.

author: wiss
author_rank: Frequent Contributor
timestamp: December 17, 2014, 04:35:40 pm
content: Thanks!

author: SeanB
author_rank: Super Contributor
timestamp: December 17, 2014, 05:31:55 pm
content: You will also need the plastic extraction tool, and new socket inserts. Those are available from RS in the circular military connector side. 19 pin circular locking connector.http://docs-europe.electrocomponents.com/webdocs/009a/0900766b8009a033.pdfRS part 494-521 seems to be the one you want.

author: helius
author_rank: Super Contributor
timestamp: December 17, 2014, 06:29:21 pm
content: You need to look closely at the part number on the connector. PT 06 E 14-19 S is a MIL-C-26482 Series I "Matrix" connector with (non-removable) solder contacts, MS3116. The removable crimp contact version would be labelled "PT 06 SE". So you will need to desolder the wires from the contacts in the connector you have. It would be best to cut the wires first to avoid damaging their insulation.Seehttp://www.amphenol-aerospace.com/pdf/12-070.pdf