hybridfree/eevblog-posts huggingface dataset:
Repair a Samsung Syncmaster 213T. Two AO4600 Mosfets and one fuse dead. - Page 1
Forum section: electronics / repair

author: The Real Phoenix
author_rank: Newbie
timestamp: December 10, 2015, 06:58:56 pm
content: Hi everyone!I'm not sure if I should post this in the newbie section or here. Sorry if I'm I'm wrong.I'm currently trying to repair a Samsung Syncmaster 213T.I've successfully changed all the caps and it's somehow working again: the inverter board doesn't powered correctly the top fluorescent tubes (so top-half of the screen is darker).After some research it seems I have one dead SMD fuse and 2 dead Mosfets.Here's my two questions:- the AO4600 is obsolete. I can find some on Ebay from China but I would like to get them quickly and be 100% they are working (I'll order on Digikey eventually).I read some people used some AO4619 but again, it seems obsolete.AO4616, ZXMC 3A16/3A17 and DMC3021LSD seem compatible but I want to be sure which one I should use.- I want to replace a fuse (and not put a jumper) on the inverter board, but it couldn't find anything on service manual about it.The only reference on the service is manual is a global reference to the inverter board:BN44-00088A --- INVERTER ---- PC213T,K02I058.00,250Hz,14V,2.5mA,6.0mA,535Hz,174.3*80*11.5,6 Lamp,50KHz,1200Vrmso I have no idea what I have to put. I took a picture, and there's only a logo which looks a "4" on it.Here's the pic:I know it's impossible to know what value the fuse is without the service manual, but is there any way to guess it?The board seems to be feed by two 14v (pin 1 and 2 from CN1), then it goes to the two fuse F51 and F101. After that it feeds the 220uF 25v capacitors (C54/C55, and C104/C105).I've probed the amps on the valid fuse (So I supposed its like shorting it) and I go 0.05A (50mA?) and the fuse seems to be a 1206 (3216 metrics) SMD package from its size.Could it be a resettable fuse?I was think of replacing the mosfets, swap the fuses to check with the valid one if the new mosfets are correct, then buy a bunch of fuses with different amps.What could be the best solution for replacing this fuse?Thanks!PS: sorry for my bad english, I'm french. ^^
How do I find live tube amp help via Skype or in person in Miami Florida - Page 1
Forum section: electronics / repair

author: Planobilly
author_rank: Regular Contributor
timestamp: December 06, 2015, 02:51:15 pm
content: Hi guys,I really think I need someone to show me how to go about doing some testing using the equipment that I own. I think for example that I do things in a safe manner but lacking experience I would like some feedback from someone who really understands tube amps.Best case, someone here in south Florida. Second best case, someone over skype. I don't have a lot of money but I can pay what ever is reasonable. I need some real time guidance.Any recommendations??Thanks,Billy

author: picandmix
author_rank: Frequent Contributor
timestamp: December 07, 2015, 10:16:50 am
content: In case there is no single person around to offer you the one to one help you are seeking,why not put some basic questions to this forum along with some details/ pics of what test equipment and amps you have and the problems; surely a much wider knowledge base, the whole point of the forum ?

author: Planobilly
author_rank: Regular Contributor
timestamp: December 09, 2015, 04:27:06 am
content: Thanks,I have been working hard to try to fix a 30W tube amp. I finally got to the cause of the problem which was a bad jumper wire between to PCB's. I spent a ton of time finding the issue and I am sure there was a better way to go about it. I have a couple of other amps that I need to repair so in a few days I will post something.I also actually ran into someone who is coming over next week to give me a bit of help.Thanks,Billy

author: highlux
author_rank: Contributor
timestamp: December 10, 2015, 06:25:51 pm
content: Signal injection and tracing are the key to amp repair after you have used your eyes, ears, nose, and brain to inspect it.Many want to fix amps. Few do.
What is this connector - like Molex, but isn't. - Page 1
Forum section: electronics / repair

author: ajrabassa
author_rank: Contributor
timestamp: December 13, 2015, 02:42:51 am
content: Here's head on, top and bottom pictures:http://imgur.com/a/t5wwRI've done a few days of research and cannot figure out what this connector is. Came out of a LeCroy 9324. Writing on the connector says "400 V" and "AL 6 2.5" followed by a square.It's about 20% longer inter-pin spacing than Molex. The male pins are on the board, and the female pins are in this connector. They appear to be just slightly smaller than Molex, as a male Molex pin will start to make contact, but quickly stop.Other suggestions to connect are welcome. I would also be fine using alligator clips, but I can't get alligator clips to make good contact on either end, and this is a power connector.Edit:I should clarify, what I mean by "is not a molex" is that the pin size is not .093".

author: Brumby
author_rank: Unknown
timestamp: December 13, 2015, 03:45:48 am
content: Don't know if I'm in the right ballpark - but I found this style from Silverstone...

author: Brumby
author_rank: Unknown
timestamp: December 13, 2015, 03:47:10 am
content: Hmmm... On closer inspection, probably not.

author: klunkerbus
author_rank: Unknown
timestamp: December 13, 2015, 05:48:52 am
content: Looks like AMP/Tyco Mate-N-Lok series to me.

author: Brumby
author_rank: Unknown
timestamp: December 13, 2015, 06:29:07 am
content: I think you could be right!

author: Brumby
author_rank: Unknown
timestamp: December 13, 2015, 06:40:44 am
content: If it might help, here's a link to a Farnell data sheet:http://www.farnell.com/datasheets/550024.pdf

author: ajrabassa
author_rank: Contributor
timestamp: December 13, 2015, 07:16:29 am
content: Hot damn, thanks! Looks like that's it.Based on this I'm not sure why my .093" pins didn't go in; I tried a bunch more and one eventually did fit.
Now that's what I call a repair! - Page 1
Forum section: electronics / repair

author: nfmax
author_rank: Super Contributor
timestamp: December 08, 2015, 09:22:10 am
content: http://www.theregister.co.uk/2015/12/07/akatsuki_spacecraft_in_venus_orbit/Max

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 08, 2015, 05:36:28 pm
content: QuoteHey! I've had repair projects last longer than that!

author: 6581
author_rank: Unknown
timestamp: December 08, 2015, 06:29:10 pm
content: It's not exactly rocket sci... Oh. It is. Impressive recovery. Makes my day job look like child's play.

author: MagicSmoker
author_rank: Super Contributor
timestamp: December 09, 2015, 12:16:22 pm
content: Yeah, thanks for posting this - I love "fix it at any cost" stories. Much more interesting than the mundane economic reality I live in...

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 09, 2015, 05:53:34 pm
content: Wouldn't it be fun to see that show up in Mailbag!
Tektronix 2230 repair hint - Page 1
Forum section: electronics / repair

author: Urs42
author_rank: Unknown
timestamp: December 09, 2015, 01:06:16 pm
content: One small hint that can save you a lot of time, if the screen looks likecheck if the X and Y plate connectors did fall of and are shorting to ground. It's not easy to get an good picture of the connectors, i hope you can see it in the attached picture.

author: tautech
author_rank: Super Contributor
timestamp: December 09, 2015, 08:23:11 pm
content: Have you checked all the LV PSU rails are to spec for voltage AND ripple?Unusual trace behaviour like yours PSU is where I'd check first.This may be of assistance:http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf

author: MarkL
author_rank: Unknown
timestamp: December 09, 2015, 08:43:06 pm
content: I think the OP is saying the scope is fixed. The post is a demonstration of what it looks like when a plate connection falls off.

author: tautech
author_rank: Super Contributor
timestamp: December 09, 2015, 08:50:21 pm
content: Quote from: MarkL on December 09, 2015, 08:43:06 pmMaybe, I'm not sure I read that from the vid.Anyway hopefully he'll come back and confirm.

author: Urs42
author_rank: Unknown
timestamp: December 10, 2015, 07:49:35 am
content: Yes, the scope does work now.
Do real repair shops still exist in Oz and if so, where can I find one? - Page 1
Forum section: electronics / repair

author: jonwil
author_rank: Contributor
timestamp: December 01, 2015, 12:30:42 pm
content: I have a Nokia N900 mobile phone (a phone that, for all sorts of reasons I wont go into here, I have zero plans to replace with an iPhone or Android device anytime soon) with a USB connector that is failing. Its a known fault with the phone and there are repair instructions online. Only problem is, I dont have either the tools (soldering iron, special screwdrivers, multi-meter etc) or the skills/know-how to try a repair myself so I am wondering if anyone knows of any repair shops in Brisbane (or SEQ more generally) that can still do board level work rather than just replacing broken screens and stuff like most shops seem to do these days...Google isn't showing any useful links so I am hoping someone out there knows of a way I can get my precious phone fixed so I dont have to buy a brand new expensive phone that wont be anywhere near as good as my trusty old N900.

author: AlfBaz
author_rank: Super Contributor
timestamp: December 01, 2015, 12:40:09 pm
content: Assuming there are monthly computer fairs/markets up there, go to one and ask around. They may even repair it while you wait

author: jonwil
author_rank: Contributor
timestamp: December 01, 2015, 12:48:16 pm
content: I am not aware of any such markets in Brisbane and Google isn't helping me out with that either.

author: nowlan
author_rank: Frequent Contributor
timestamp: December 01, 2015, 01:29:15 pm
content: There are heaps of mobile phone repair stores. Im sure they can solder a new connector for you.

author: briselec
author_rank: Regular Contributor
timestamp: December 01, 2015, 09:05:21 pm
content: Maybe someone at hackerspace will help you fix it.http://www.meetup.com/hackbne/

author: jonwil
author_rank: Contributor
timestamp: December 01, 2015, 10:09:14 pm
content: Quote from: nowlan on December 01, 2015, 01:29:15 pmThe chops I have tried so far dont seem to do solder work, they just replace bits (e.g. broken screen or whatever)

author: jonwil
author_rank: Contributor
timestamp: December 02, 2015, 11:21:37 am
content: Whoever suggested hackbne, thank you for that, I have posted on their "bazaar" forum asking if anyone can help me out (since that seems to be the most appropriate forum to post such things on)

author: jonwil
author_rank: Contributor
timestamp: December 08, 2015, 03:00:38 pm
content: Went to the HSBNE open evening and I dont know exactly what they did to my phone but it seems to be working now. YAY
ft-901dm ham radio repair. - Page 1
Forum section: electronics / repair

author: drforbin
author_rank: Regular Contributor
timestamp: December 08, 2015, 03:02:40 am
content: Hi guys. I don't know if this is the proper place to ask for help related to ham radio repair, but I thought I'd try anyway.I am currently trying to repair a ft-901dm ham radio.I'm having problems if transmitter power output.When turned up on 160, 80,20 I'm getting close to full power on 20m I'm getting only 10 watts.I tracked it down to ALC circuit (this circuit is pretty simple. If anyone wants schematics I can provide them) It seems that on some bands, 20m in particular the ALC is preventing the PA from reaching full power. I tested all the caps and traced the circuit, even going as far as changing most of the caps associated with the ALC. NO good. I really cannot figure out whats going on. I really need some help or suggests to put me on a new path.Ok thank you all for reading.any suggestions will be welcome.Drforbin.PS. I have neutralized the tubes.
not the same yam reciever issue - Page 1
Forum section: electronics / repair

author: jwfirebird
author_rank: Newbie
timestamp: December 08, 2015, 12:40:48 am
content: have a rx-v667, also have the manual but haven't been able to figure this out. it shuts down like the video, has PS PRT: 1L on the diagnostic screen. it has the 2 +5v's to the digital one card, they read 5.55. has the 3.3 to the button area. i have looked at the ones on youtube and that and i dont have the cap those PS's have. closest thing i have is c3709, and 19 i believe that look like that and they are stuck together with heat sink compound. trouble is the units you put up look nothing like the one i have. also i checked the output transistors, they are not reading shorted.? in protect disable the relay that brings in the big Tx clicks on and off at random every couple minutes.anyone know what i should check or more info on whats wrong?·
Auditec Power Amplifier Module - Page 1
Forum section: electronics / repair

author: Raff
author_rank: Regular Contributor
timestamp: December 06, 2015, 07:01:19 am
content: Hi everyone.I'm trying to repair a 1970s home made guitar amplifier.Inside it has 2 Auditec 001 MK2 modules.They have 2 2N3055 as output devices, and the diode rectifier bridge is on board, but the filter caps are off board.I've found a few faults such as a shorted 2N3005 and its driver a BD140, but when I power it up carefully using a variac and dim bulb tester, I get over 5 volts DC across my 8 ohm dummy load on the speaker terminals.I suspect something else is faulty although all the semis check ok on my meter.Anyone have a circuit diagram for these?From memory I think Delsound in Brisbane at least used to sell these in the 1970s.Thanks,Raff

author: SeanB
author_rank: Super Contributor
timestamp: December 06, 2015, 10:42:21 am
content: Check the low value resistors on the power transistors, if the one dies as a short then the resistor would have either changed value or gone open circuit. The other transistors could test as fine, but could still be leaky at full operating voltage.Pics of course will help.

author: Raff
author_rank: Regular Contributor
timestamp: December 06, 2015, 10:53:31 am
content: Thanks for the info.I'll grab some pictures tomorrow and post them up as well as checking the resistors.Thanks,Raff

author: DrGeoff
author_rank: Frequent Contributor
timestamp: December 06, 2015, 11:27:55 am
content: Auditec, that was Cyril Murray's company. I remember them from back in the 1970's.If you have replaced the 2N3055 transistors, did you check the bias circuit?There is probably a transistor in there (eg BC549) use to tempco the driver bias.

author: Raff
author_rank: Regular Contributor
timestamp: December 07, 2015, 04:50:41 am
content: Here are a couple of pictures of the modules.One has had the driver transistors changed to BD139 and BD140 but is otherwise identical to the other.I've had more of a muck about and it seems that maybe the power amp modules are actually working fine, as when I move the volume control, that's when I get a DC output on the speaker terminals.Its not just when I move it but the DC stays there after as well.I've put it on the back burner for now as the pre amp module is pretty rough looking and Id hazard a guess that the electros I see on it are probably causing the DC out problem.Raff

author: picandmix
author_rank: Frequent Contributor
timestamp: December 07, 2015, 10:09:02 am
content: If you are looking to keep using those amps then I would spend an hour or so drawing out the circiut diagram for future use.When repairing such old boards, it often cheaper and simpler to replace all the transistors / diodes and electros, as replacing just one part often leads to a daisy chain effect of failures.On some old boards I find it easier just to strip everything off and use all new parts, most are just cheap resistors and caps.If the pre amp is rough, you can probably find a suitable circuit here, some designs also have a ready made pcb; have bought them before and they are good quality.http://sound.westhost.com/projects.htm
OBD II wifi module - Page 1
Forum section: electronics / repair

author: ktulu
author_rank: Regular Contributor
timestamp: December 05, 2015, 05:19:40 pm
content: I have an ELM327 WIFI OBD II module:http://www.dhgate.com/product/good-quality-elm327-wifi-obd-ii-car-diagnostic/161047564.htmlI made the mistake? to change it from Ad-Hoc to Infrastructure on it's web page.The module is no longer visible no matter what i do.Before it showed up in my wifi list as WiFiOBD.Any help is wecome to make it work again.Thanks.(There are 2 PCB's inside, one of them is the wifi module which has a red status LED.After powerup the LED blinks a couple of times and then remains lit. (did the same when it was visible)I noticed that if I change my router's SSID to the same WiFiOBD, and than power up the module, the LED after it blinks goes out. So the module can detect someone else using the same name nearby, and shuts itself off. So it's doing something)

author: Fraser
author_rank: Super Contributor
timestamp: December 05, 2015, 05:42:30 pm
content: With my RS232 to wireless modem links If you effectively lock out Wireless by a configuration error, you have to go into the configuration directly through the RS232 port rather than 'over the air' configuration. There may be an RS232 port available but you may need a configuration client to reset the module to defaults.Fraser

author: ktulu
author_rank: Regular Contributor
timestamp: December 05, 2015, 06:07:40 pm
content: The module is equipped with an STM32F103 ARM micro, and the USART2 Rx and Tx are routed out to 2 vias.Other than that, it also has the Rx Tx lines to the ELM board. (these might be RS232 lines, probably this is just an RS232 to wifi adapter PCB) But what next?

author: ktulu
author_rank: Regular Contributor
timestamp: December 05, 2015, 06:35:17 pm
content: OK, with the router set to the same SSID, I finally am able to reach the module on 192.168.0.10 (thanks to some help from the hobbielektronika.hu forum)In infrastructure mode the module is trying to connect to the same SSID network, rather than creating one.

author: Fraser
author_rank: Super Contributor
timestamp: December 05, 2015, 07:28:41 pm
content: Good news.Well doneFraser

author: ktulu
author_rank: Regular Contributor
timestamp: December 05, 2015, 08:14:18 pm
content: Thank you.
These circuit boards have bugs... - Page 1
Forum section: electronics / repair

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 05, 2015, 04:20:32 am
content: Tracking down the problems.

author: Rerouter
author_rank: Super Contributor
timestamp: December 05, 2015, 04:25:12 am
content: That is nothing... cockroaches love warm electronics in buses, now imagine opening up the casing, and not finding a single mm not occupied by dead cockroach... the entire board dissolving in bug piss and excrement, and your in the middle of nowhere with no spares
Found 360 Heatsink Mount Solution - Page 1
Forum section: electronics / repair

author: DirkyDirk
author_rank: Newbie
timestamp: December 04, 2015, 05:54:20 pm
content: Hello, I found this solution for cutting up the metal casing of the 360 to mount the 360's heatsinks in a different way.http://therealundamned.blogspot.com/2009/06/preventing-xbox-360-rrod.htmlSince this is an unknown source well before the Team Xecuter bolting your board drama and it has very little proof, I assume this person means well, but of course good intentions aren't enough when it comes to fixing bad hardware. Is this fix reliable or is it just another farce that won't do anything else than mutilate your consoles. Also what about this?http://www.se7ensins.com/forums/threads/air-fan-shroud-modification.462856/I assume that fix is 99.99% effective since it allows air to pass through the fins instead of the fins just being there as a passive cooling solution since very little air is moving through the fins without that simple modification.I hope asking this isn't too much trouble and thank you to those who answer or at the very least read this. I just want Phat 360 owners to get the best out of their system being one myself and I'm bad at airflow management.

author: DirkyDirk
author_rank: Newbie
timestamp: December 07, 2015, 08:03:19 am
content: I hope it's okay to bump this, but I'm just curious if these solutions are good or not. It would help out plenty of 360 users and save them quite a bit of money if so. Sorry for the bump.
Can anyone identify this part? - Page 1
Forum section: electronics / repair

author: switch998
author_rank: Contributor
timestamp: December 06, 2015, 07:58:07 pm
content: Hi guys,I'm having a bit of trouble finding the manufacturer of this part, it's a cable card card slot from a set top box and I need another for a second box that I'm working on. I don't recognize the logo and my searches have come up with nothing.Does anyone recognize the logo on this?

author: SeanB
author_rank: Super Contributor
timestamp: December 06, 2015, 08:03:01 pm
content: Google for PCMCIA socket, which is what that is. Most should fit there and mate with the board.

author: switch998
author_rank: Contributor
timestamp: December 06, 2015, 08:18:24 pm
content: Yes, I know that, but I need the original part. Reason being, I wouldn't be able to mount a generic PCMCIA slot into the STB since I can't find any that are secured from the side rails like this one is, also, on the board end, most PCMCIA slots have a different style connector than this.

author: miguelvp
author_rank: Super Contributor
timestamp: December 06, 2015, 08:48:47 pm
content: Brand and model of your set top box might help on the search.

author: switch998
author_rank: Contributor
timestamp: December 06, 2015, 08:52:11 pm
content: Quote from: miguelvp on December 06, 2015, 08:48:47 pmIt's a TiVo Roamio

author: miguelvp
author_rank: Super Contributor
timestamp: December 06, 2015, 10:57:53 pm
content: No luck and probably a custom job for Tivo.Maybe put a watch on ebay for a broken unit for parts only.
So.  This famous 'brown glue' on circuit boards.  How to remove it? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: December 02, 2015, 04:09:27 am
content: This is the stuff that can cause trouble over time by going conductive, or even corrosive. Is there any effective method to deal with it? Can it be somehow removed, or is it pretty much a nightmare trying to get rid of it?Is this just a consumer electronics thing, or does professional / industrial gear have it too? Thanks.

author: SeanB
author_rank: Super Contributor
timestamp: December 02, 2015, 04:34:12 am
content: Freezer spray then scrape it off while still frozen works best. Solvents that can attack it tend also to be bad for components, so scraping generally is best. Does not have to all be off, just mostly so it will not track between parts and pins. A dental pick is best to get it out from pins. Finally yes it appears all over, though the better manufacturers will not use it, but will use an acetoxy free silicone instead, or a polyurethane epoxy that sets like rock.

author: tautech
author_rank: Super Contributor
timestamp: December 02, 2015, 04:58:44 am
content: Cut a small piece from it and if it seems porus like foam remove it, it will be hygroscopic and absorb moisture especially when powered down for a time or put into storage. Then if you power it on.....boom.Seen it in proprietary slimline HP PC PSU's.

author: wraper
author_rank: Unknown
timestamp: December 02, 2015, 02:00:37 pm
content: I'd say if there is not sign of corrosion, then don't bother. It would be really stupid to destroy the device while trying to prevent "possible" malfunction in the future. Also, there might be multiple types of the glue which look similar but aren't the same. At least I didn't notice that the presence of such glue = 100% corrosion in the future. Also if this glue isn't over the tracks but just holding the parts to copper free area of the PCB (like large capacitors), I wouldn't bother at all.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 02, 2015, 03:06:16 pm
content: Picture of the "brown glue area" speaks volumes.

author: free_electron
author_rank: Super Contributor
timestamp: December 02, 2015, 03:59:04 pm
content: you meanhardened flux ?flux remover or some isopropyl alcohol will do fine.

author: Len
author_rank: Frequent Contributor
timestamp: December 02, 2015, 04:28:13 pm
content: Quote from: free_electron on December 02, 2015, 03:59:04 pmNo, he means this:https://youtu.be/yy8NS2zejhQ

author: wblock
author_rank: Regular Contributor
timestamp: December 02, 2015, 05:10:35 pm
content: An interesting video, unfortunately marred by the #1 rule of instructional videos: "Light is the enemy."Here are some quick examples pulled from my junk pile.
Disconnecting small connectors - Page 1
Forum section: electronics / repair

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 29, 2015, 09:58:12 am
content: Hello,Could anyone tell me how to release the flex printed cable from the two connectors in the pics below. I am familiar with the other connectors on this PCB that have a 'lift-up bar', but am unclear with these two. Before I start pulling and tugging I thought I would ask !The flex cables are from the lens unit in a Fuji F770EXR. It appears to have grit in the telescoping lens system and the lens protective shutter does not open all the way- but the owner sprayed WD40 down the lens to try to rectify the fault.No-one told me that retirement would be like this !Regards, BT

author: rch
author_rank: Regular Contributor
timestamp: November 29, 2015, 02:58:01 pm
content: I'm fairly sure the horizontal one in the middle picture works by disengaging the "ears" at each end of the grey bit outward from the pegs on the white bit, and sliding the grey bit a few millimeters horizontally away from the white bit along the flex connector. Not sufficiently sure about the other picture to comment.

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 30, 2015, 01:50:18 am
content: Thanks for that, RCH. I did try to gently pry the latching tabs and push the grey bit away from the white part but it was reluctant to move.The white connector is a bit of a mystery.I will delay in case any one else has any experience of these types.I suspect that the lens unit is beyond economical recovery actually, but did say that I would 'have a look'.BT

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 30, 2015, 11:52:11 am
content: OK, the white connector- the end of the flex is more rigid and it just pulls out with the aid of long-nosed pliers.I am still struggling with the other connector.BT

author: rch
author_rank: Regular Contributor
timestamp: November 30, 2015, 11:31:18 pm
content: You'll have to see if anyone else recognises the other connector, or if there is any similar bit wedging the flex that can be pulled out.

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: December 01, 2015, 03:29:33 am
content: Woo Hoo!I am the Enlightened One-The black and white connector is released by lifting the WHITE part of the assembly. This is the part furthest from the flex ribbon.I have not seen this type before, as I have only experienced a similar looking type where the part nearest to the ribbon lifts up to release the ribbon.Strange really, as two other connectors on the same small PCB are black and white but operate in the opposite way.These things are sent to try us...Regards, BT

author: rch
author_rank: Regular Contributor
timestamp: December 01, 2015, 07:53:03 pm
content: Well done. Good luck with the lens - doesn't sound too good.
Help to repair an Icom R72 receiver - Page 1
Forum section: electronics / repair

author: mehdi
author_rank: Regular Contributor
timestamp: December 01, 2015, 12:28:55 pm
content: HiIt is my first serious attempt at repairing a receiver and I need help.I've got an Icom R72 communications receiver.It's deaf on frequencies between 11.000 MHZ and 14.999 MHZ, but working on other frequencies (I've tested local AM stations and 7, 18 and 21 MHZ )The service manual states that there are 6 bandpass filters and one of them is for 11-15MHZWhen I connect the output of my signal generator to its antenna input (for example with a 14MHZ signal), I can hear a tone which changes when I change the modulation on signal generator.I'm not sure whether the oscillator is not working or the bandpass filter is faulty.Can someone help me on my next step to find the faulty part?Here's the service manual:www.radiomanual.info/schemi/IC-R72_serv.pdfTools that I have: Oscilloscope, DMM, signal generator (with AM/FM modulation), frequency meter.Thanks

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 01, 2015, 12:44:00 pm
content: Check the diodes that switch the BPF, I think it is D31 and D32 for 11-15MHz.Also check that the output of IC3 correctly powers the diodes for each band.
How to find the right transducer without having the part number? - Page 1
Forum section: electronics / repair

author: theBigK
author_rank: Contributor
timestamp: November 19, 2015, 04:32:25 pm
content: Hello everyone,I am repairing one of our tools, and the replacement is expensive. Unfortunately, I was impatient in waiting for my desoldering gun. (That I decided to pick up after seeing Dave use one often) I used a hot air gun to desolder it.Well well well... The back of it melted, I can make out 3 characters, and the rest is toast.I was wondering what one does in this situation? Do I attempt to order one, solder it on and cross my fingers? Is there a way I can test what I have?I did not NECESSARILY damage them, the back is melted, but I assume it might still be holding a vacuum and be working...not sure how to test one?This site had a few of them.http://www.mmselectronics.co.uk/smtspd.htmBesides testing it, I figured I could read the machine specifications and operating pressures and make an educated guess on what the sensor ranges SHOULD be?My last hope was finding a broken one of these, buying the board, and desoldering the sensor (properly) and then reading the back of it.All and any information is appreciated in this case.

author: theBigK
author_rank: Contributor
timestamp: November 25, 2015, 06:22:14 am
content: I will bump this up one more time, I can't get my hands on a used one so I am going to just try to replace this one with a guess and cross my fingers.

author: theBigK
author_rank: Contributor
timestamp: November 30, 2015, 05:08:11 pm
content: Added some photos

author: theBigK
author_rank: Contributor
timestamp: December 01, 2015, 02:44:05 am
content: So I found it.How can I test my current sensor to try to determine which one I have?Absolute or gauge pressure, and the psi range?
IPC 7711/21B Reworking guidelines any good? - Page 1
Forum section: electronics / repair

author: fubar.gr
author_rank: Unknown
timestamp: November 30, 2015, 02:38:09 pm
content: Somebody mentioned the IPC 7711/21B reworking guidelines on the Rossmann thread.The document can be bought from here:https://portal.ipc.org/Purchase/ProductDetail.aspx?Product_code=C4D14F3D-48CD-DC11-AFC9-001422202D38Almost $300 is a lot of money. I have no problem paying that amount, as long as the material is good and worth it.But somehow I feel that 98% of that will be stuff I already know.So, is this only good for certification purposes (which I don't need), or am I going to learn something useful?

author: FireFlower
author_rank: Regular Contributor
timestamp: November 30, 2015, 04:58:40 pm
content: It is pretty much the holy bible how to rework stuff so you could sell fixed stuff also to customers. For hobbyist I think it is not necessary even though it is well written guidelines how to fix anything PCB related. It is meant mainly for professionals who need standards for their work.Basically it covers reballing BGA's, foil fixes, jump wires, how to take stuff off, acceptable results for repairs etc etc etc. I can't remember everything that is there but I think it has about 300-500 pages. Perhaps you should ask Dave about it, I would think he has it somewhere around his lab.
RIGOL DG1022: overload protection - no output on channel 1 - Page 1
Forum section: electronics / repair

author: hb9bnk
author_rank: Newbie
timestamp: August 11, 2014, 03:17:49 pm
content: I managed to produce a short circuit in my workshop and after repowering-up, the DG1022 works now only on Channel 2. ->Utility->Test reports 'overload protect' when channel 1 is selected.My local supplier has no spare parts any more.Does somebody know, what I would have to replace ? Is there a schema/diagram ?Thanks very muchWerner

author: hugos31
author_rank: Regular Contributor
timestamp: November 30, 2015, 12:56:19 am
content: https://www.eevblog.com/forum/testgear/rigol-dg1022-problem/msg451006/#msg451006
Suggestions Request: Wireless Data Logger for Equipment Troubleshooting - Page 1
Forum section: electronics / repair

author: Denton.Hess
author_rank: Newbie
timestamp: December 03, 2015, 04:34:34 am
content: Hi Everybody:I am new to the group. I am an equipment maintenance tech in the semiconductor industry, and here is my issue:Every once in a while I would like to hook up to Analog and Digital data logging test points, in different places all over a piece of equipment, to isolate an intermittent fault.I rarely have access to any ladder logic diagrams, and never have access to software code flow charts, so, as I am sure some of you can sympathize, I make do the best I can. Usually that means isolating candidate test points through available schematics.My dream would be to have wireless transmitters that I could hook across ground and the signal testpoint I want to monitor, verify transmission, and walk away. But I am concerned about RFI issues generated by a wireless solution, and I have no idea what is currently available for this applicationAdditionally, the data capture software, would ideally be, inexpensive.Your thoughts?Thanks, I appreciate your time to respond.

author: petieken
author_rank: Contributor
timestamp: December 03, 2015, 07:39:17 am
content: I don't know how far apart your test points are, but maybe something like this can be helpful. I'm currently in the process of trying to get a Raspberry Pi running with some ADC's connected to it to do some logging. I have almost no programming experience but I'm slowly getting some results. I will be using wired ethernet but you can plug in a wifi dongle if you want wireless.

author: Circuitous
author_rank: Unknown
timestamp: December 03, 2015, 02:19:43 pm
content: Quote from: petieken on December 03, 2015, 07:39:17 am@petieken. That sounds interesting, I hope you can share your project with us as it progresses.Sent from my SPH-L720 using Tapatalk

author: Denton.Hess
author_rank: Newbie
timestamp: December 03, 2015, 02:37:02 pm
content: Quote from: petieken on December 03, 2015, 07:39:17 amHere is a similar project I saw that you might request to join: hackaday.io/project/7601-open-source-data-logger-rpi
Fluke PM-6304 Programmable Automatic RCL Meter - bad display - Page 1
Forum section: electronics / repair

author: Rutger
author_rank: Regular Contributor
timestamp: November 26, 2015, 03:51:15 pm
content: The display on my Fluke PM-6304 isn't working, any tips on how to fix this?

author: HighVoltage
author_rank: Super Contributor
timestamp: November 26, 2015, 05:39:13 pm
content: Did the display just stopped working?Can you be more specific?I only have the PM6303A and the PM6306May be you can open the unit and take some picturesHere is a picture of the inside of the PM6306May be you are lucky and it is a loose connection of the ribbon cable to the display, as I had it once on a PM6303A

author: Shock
author_rank: Super Contributor
timestamp: November 26, 2015, 11:45:24 pm
content: Are you experienced in repairing? Have a multimeter and a oscilloscope?I'd start by removing power from it then reseating the cables.https://doc.xdevs.com/doc/PHILIPS/PM6304/PM6304_Service_manual.pdf
IET VI-700 Voltage And Current Source - Page 1
Forum section: electronics / repair

author: Rutger
author_rank: Regular Contributor
timestamp: November 26, 2015, 03:49:25 pm
content: Looking for service manual and/or schematic. Trying to repair unit, 5V regulator is getting way to hot and the big resister near by as well. Without schematic and need help.Thanks.Rutger
chipped inductor still functional? - Page 1
Forum section: electronics / repair

author: WhiteFireDragon
author_rank: Regular Contributor
timestamp: November 22, 2015, 08:13:48 pm
content: I have a audio DAC that has one of the top pieces cracked, however all the coils are still intact and tightly wound. Should I get it replaced, or will this not affect the functionality of it? Picture of the crack below:

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2015, 09:51:01 pm
content: If U101 gets hot in operation (or other things act funny?), it should probably be replaced, yeah.If the central stem of ferrite is cracked and loose, it should probably be replaced.You can try supergluing the bits back on. Ferrite and superglue work nicely together.Tim

author: WhiteFireDragon
author_rank: Regular Contributor
timestamp: November 22, 2015, 09:57:55 pm
content: So just to confirm, that part that chipped off does not provide any electrical or thermal functionality? The central stem and copper coils seem to be all good.And can someone help me source a replacement for this damaged inductor? The only indication on the it is "102", and that's not enough info for me to find the same part number.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2015, 10:15:50 pm
content: The black ceramic provides a path for magnetic fields. By having somewhat less material, the inductance value will be lower.It's probably not far out of tolerance (-20%, maybe?), which I would guess is still close enough for the nearby components. But it might not be, hence my warning."102" is most likely 1mH. The current rating will be determined by the wire size... which is determined by how big the thing is to begin with. What diameter and height is it?You could also check DC resistance, but it's probably under an ohm, so you'd need a special meter to be sure.The package is a standard format from e.g. Bourns, etc. and probably costs under $1 (you'll spend more on shipping and handling).Tim

author: lukaq
author_rank: Regular Contributor
timestamp: November 23, 2015, 10:41:32 am
content: you could super glue them back on, far better than not having them

author: JoeB83
author_rank: Regular Contributor
timestamp: November 24, 2015, 08:49:36 am
content: Is that an ODAC? If so, the same happened with me, still works well.
Dead APC Back-UPS RS 1000 - Page 1
Forum section: electronics / repair

author: berkutta
author_rank: Newbie
timestamp: November 23, 2015, 03:38:57 pm
content: HiHave here a USV which died through a dead computer PSU (short circuit). Now it only response with the "overload" sign on startup. I think there's something wrong with the mosfet stage or something like that due the short circuit. There are no burned parts or anything else obvious. A Battery Change doesn't changed anything on it. APC doesn't want to give out any repair manuals or schematics or anything else.Are there here any persons who has knowledge on such things? What do you think about that? What would you do first on it?Benjamin

author: berkutta
author_rank: Newbie
timestamp: November 24, 2015, 07:43:30 am
content: got it working again, dismounted the two mosfet stages on the top left and from 6 mosfets are 2 dead. Replaced them and it works fine again
Help fix LED flicker - Page 1
Forum section: electronics / repair

author: cryptlabs
author_rank: Contributor
timestamp: November 22, 2015, 07:43:47 pm
content: Hello,I have an led strip 12v DC connected to a switching power supply which also runs my cnc machine. When the machine is on load the led flickers but not when the cnc is idle. How can i make the led stable?Regards

author: max666
author_rank: Frequent Contributor
timestamp: November 23, 2015, 12:31:40 am
content: Put in a diode and an electrolytic capacitor before the LED strip.

author: cryptlabs
author_rank: Contributor
timestamp: November 23, 2015, 01:43:04 am
content: Quote from: max666 on November 23, 2015, 12:31:40 amThanks for the reply What size and kind for the components?

author: cryptlabs
author_rank: Contributor
timestamp: November 23, 2015, 01:52:37 am
content: I tried a 1n4001 diode with a 450 microfarad capacitor but its not working.

author: TheSteve
author_rank: Unknown
timestamp: November 23, 2015, 04:44:17 am
content: The power supply is dropping voltage because of the load of the CNC - the proper solution is to get a second power supply just for the LED lights or get a power supply capable of more wattage to power both.

author: max666
author_rank: Frequent Contributor
timestamp: November 23, 2015, 11:28:14 am
content: Quote from: cryptlabs on November 23, 2015, 01:52:37 amWell, without knowing any more detail about your LED strip, I would have gone with at least 10 times that capacity, if I had to guess.If I do some very crude napkin math, and assume you have a 5 W @ 12 V LED strip. Then the current would be 0.4 A, so the load resistance the LED strip provides would be 29 Ohm. A 4500 µF cap and a 29 Ohm resistance have a time constant of 0.1 s (after that time the cap would be dischared to 37% assuming an ohmic load), so if we go for maybe a third of that we would be able to bridge a drop for about 0.04 s. I feel like that would be barely enough, so I guess you need at least 4500 µF for a 5 W @ 12 V LED strip. But then again I don't know how long your voltage dips out or how much power your LED strip has.Or use a separate power supply like Steve suggested.I hope you're not powering any logic from that 12 V power supply as well.

author: djQUAN
author_rank: Frequent Contributor
timestamp: November 23, 2015, 12:14:53 pm
content: As we are working with little info here. Could be the wire going to the supply is dropping the voltage? How about running separate wires from the CNC and the LED strips going back to the supply?

author: cryptlabs
author_rank: Contributor
timestamp: November 24, 2015, 04:21:50 am
content: This is my led and power supply. The led needs 12v 105ma.The power supply is rated at 12v 10A.
Tektronix 465b repair - Page 1
Forum section: electronics / repair

author: Aerobyrd93
author_rank: Contributor
timestamp: November 22, 2015, 02:01:21 am
content: Hi there,It's hard to describe accurately exactly what the problem we are experiencing is in words, so here is a video.https://drive.google.com/file/d/0B4Q9AmjTBNNqSVhiN09pNmloUTA1cmVvNURwNWx1Z204X0RR/view?usp=sharingNo input given with probes yield no change. Any help would be greatly appreciated.

author: Cubdriver
author_rank: Unknown
timestamp: November 22, 2015, 06:14:45 am
content: I'd start with checking all power supply rails for proper voltages and ripple levels. Bad filter caps can cause all sorts of off-the-wall looking problems.-Pat

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 22, 2015, 06:20:37 am
content: Don't forget some helpful troubleshooting guides from this thread:https://www.eevblog.com/forum/repair/repair-documents-and-links-sticky-me-please-mods/

author: tautech
author_rank: Super Contributor
timestamp: November 22, 2015, 06:51:50 am
content: Link to Service manual:http://elektrotanya.com/tektronix_465b_oscilloscope_full_sm.pdf/download.html47 MB
FLUKE 5500a Calibrator  repair   help with IFC07703 fet parts & data sheet - Page 1
Forum section: electronics / repair

author: rickells
author_rank: Regular Contributor
timestamp: November 25, 2015, 06:40:46 pm
content: Fluke 5500a Calibrator repair, help with Fet or transistor IFC07703 ?Trying to solve some issues with a Fluke 5500a Multi Calibrator.Error codes on the A5 Impedance Synthesizer board:1049 & 1051Trying to find Fet part # IFC 07703 !! { listed as Q3 & Q4 in Fluke 5500a manual... no schematics either !! }in a TO-92 plastic package, also can't find data sheets for this Fet or transistor !thanks
Display repair - picture displayed with two edges - Page 1
Forum section: electronics / repair

author: ulix
author_rank: Regular Contributor
timestamp: November 21, 2015, 06:42:20 pm
content: Hi,I have here a Lenovo Thinkstation 2240 display. It's not displaying the picture correct. The edges are displayed two times. At first I tought that the vga connector is faulty but it doesn't change the picture when wiggeling on the connector.The first picture shows some color missmatch which was there but I can't reproduce. The last two pictures show the edge offset. How does this happen?I checked all connectors inside but this doesn't change anything.Does someone know how to fix this? Is the panel faulty?

author: ulix
author_rank: Regular Contributor
timestamp: November 21, 2015, 08:20:18 pm
content: 2nd set

author: nctnico
author_rank: Super Contributor
timestamp: November 21, 2015, 08:30:00 pm
content: If you get shadows then your VGA cable is of poor quality and needs to be replaced.
Can anybody tell me how this transistor opens? - Page 1
Forum section: electronics / repair

author: JGAN
author_rank: Contributor
timestamp: November 21, 2015, 03:53:37 am
content: I'm trying to fix a dead computer board. It is missing this "ALL_SYS_PWRGD" signal, which comes out of this transistor Q8150. I can't find the datasheet for the transistor, but what is confusing me are all the S0 state rails that go into Q8150. The computer should be in the S5 state if it is off, but then how is "ALL_SYS_PWRGD" created? Are all these "Q2" "Q3" "Q4" transistors within not necessary for current to flow through to the output of Q8150?Basically, is this some sort of transistor where only one source is necessary for the gate to open?

author: rs20
author_rank: Super Contributor
timestamp: November 21, 2015, 04:11:33 am
content: Q1 is a N-type MOSFET. Q2, Q3, Q4 are NPN transistors. Google for the proper terminology for the three legs for a MOSFET (gate, drain, source) and NPN/PNP transistors (collecter, base, emitter), "output" is vague.If Q2, Q3, Q4 areallturned on, by bringing their bases high enough, the gate of Q1 (same net as the collector of Q2) is pulled down to ground, Q1 is turned off, and ALL_SYS_PWRGD is open-circuit, presumably pulled high by a pull-up resistor not shown in the schematic.If any of Q2, Q3, or Q4 are off, its gate of Q1 goes high (pulled up by R8156), Q1 is turned on and ALL_SYS_PWRGD is pulled to ground (0 V).To answer your question, current flowing into the drain of Q1 flows out the source. Q2, Q3 or Q4 beingoff, combined with PP3V3_S5 being high, enables this current to flow.Keep in mind that signals are sometimes active-low, i.e. a net labelled "S5" might be low if the S5 state is active, high otherwise. This is sometimes denoted by a line over the name, or a "#" or "!". This is certainly true of the PS_ON# signal of ATX PSUs, which you must pull down to ground if you want the PSU to turn on.

author: JGAN
author_rank: Contributor
timestamp: November 21, 2015, 04:33:33 am
content: Perfect! Answered my question completely and also made me learn BJT transistors. Thanks!!