hybridfree/eevblog-posts huggingface dataset:
Need help finding replacement flat flex connector - Page 1
Forum section: electronics / repair

author: ThisDoesNotCompute
author_rank: Contributor
timestamp: July 20, 2016, 01:37:01 pm
content: Hey everyone,Long story short, while disassembling my Sony A5100 mirrorless camera I broke the flat flex connector for the LCD screen. (I thought it had a flip-up bail, when it turns out it's just friction fit -- d'oh!) It should be possible to replace the connector, but the trouble is I need some help finding one. I've been digging through Mouser and Digi-Key, but nothing looks quite right. It has 51 pins, and the contacts on the flex cable are staggered. I suspect the pitch is .2mm, but I'm not 100% sure, and it's bottom-contact. I'll try to get some more photos tonight (with an eevblog ruler for scale) of both the broken connector and the flex cable, but here are pictures of the connector, before and after the carnage. Any suggestions would be greatly appreciated!Before:Oops:

author: ThisDoesNotCompute
author_rank: Contributor
timestamp: July 21, 2016, 02:26:05 am
content: Here are additional photos of what I'm dealing with:The damaged connector. The legs that solder to the board run down both sides of the connector:The connector with ruler for scale:The bottom side of the flat flex cable, there's nothing on the other side:A look at the contacts on the flat flex, with ruler for scale:
Fool My A56405 Toyota Radio To Think It Is Playing A Cassette? - Page 1
Forum section: electronics / repair

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: July 19, 2016, 10:29:07 pm
content: Hello again everyone. I took apart my 97 toyota rav 4's original radio to modify it by adding bluetooth and a line in. I got the lines traced for the output of the head amplifier, and if I split those wires, I could inject my own audio into the radio, and it would play.However, this ONLY worked if I had a cassette playing. Once it ran to the end of the tape or the tape was removed, it stopped playing my injected audio.So I took apart the tape assembly and removed all the boards, motors, and switches from it. Then I just placed them on a plastic sheet and played with the switches until it stayed in tape mode. I got it to stay in tape mode by holding down two switches, but the eject motor and spindle motor just pulse on and off. I figured that it would be okay as long as it played audio... but it doesn't.Anyone have any suggestions for me to try to get it working without a tape in the cassette desk? I wanted to completely remove any moving parts, which is why I didnt just use an infinite tape. The mechanics in this thing are about dead anyway, they barely work and make a lot of noise.Below are pictures of the front and underside.Toyota A56405Model 86120-AC010Ref CQ-LS7410ZAny ideas? I can't find a service manual anywhere

author: lowimpedance
author_rank: Super Contributor
timestamp: July 20, 2016, 12:33:54 am
content: Just a thought, what about a car wrecking yard and a later model rav4 with a more suitable radio (cd type) if such a thing exists that could be made to fit.Seems like a lenghty exercise if easier alternatives are available.Is it that costly to just buy an aftermarket player that probably comes with USB too ? (even second hand? )

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: July 20, 2016, 02:11:58 am
content: Quote from: lowimpedance on July 20, 2016, 12:33:54 amTrying to do this without spending anything. My current Sony CDX u8000 has a missing walkman button, disk player doesn't work (who plays disks anyway?) and the LCD is starting to bleed or something.Quote from: evb149 on July 20, 2016, 12:21:44 amI have one of those tapes. It does work with it but the stereo separation is absolutely terrible. Its going to be a huge work trying to get the board and motors back into the assembly

author: SeanB
author_rank: Super Contributor
timestamp: July 20, 2016, 08:00:47 am
content: There wil be either an optosensor or a small magnetic switch that is getting pulses from the tape rotation. You need to find it and just feed in a low frequency pulse ( around 1-5Hz) to fool it into thinking there is a tape in there and it is moving.
iCharger 406DUO is sad - Page 1
Forum section: electronics / repair

author: Strepto
author_rank: Newbie
timestamp: July 20, 2016, 05:41:02 am
content: Hi all,I've got an iCharger 406DUO with a problem. It was left out overnight and got covered in dew, and unfortunately it got powered up before drying out the next day.It started acting up and now it just resets/cycles repeatedly when trying to boot. There's a ticking noise coming from somewhere on the board when it resets. Probably one of the giant inductors.Any ideas where to start - or, can anyone here repair or recommend a repairer for iChargers in Australia. I'm in Brisbane but can post it.Simple stuff I can do myself, but diagnosis of this one is beyond me.There's no sign of any physical component failure or corrosion on the board, and I've cleaned it thoroughly with isopropyl.Cheers!Mark
Netgear FS105 Switch Repair - Page 1
Forum section: electronics / repair

author: Obsidian_ShadowHawk
author_rank: Contributor
timestamp: July 10, 2016, 03:53:21 am
content: Hello! I picked up a Netgear FS105 10/100 switch at a second-hand store. Looks like U1 is blown out. I can only make out "...34063" Top result on the web looks like MC34063. Does anyone have this switch and can confirm? These things are cheap on Amazon, but the chip is cheaper on Digikey, and the soldering experience is great for a noobie like me.Thanks!Pics:https://www.dropbox.com/sc/h2cyy8n4tkfn2tk/AABwqqGC02UuCgYL5GkvpvUUahttps://www.dropbox.com/sc/m2312m7sh29gghv/AAAoRvbZ12nzOFvet3uV-iEta

author: LabSpokane
author_rank: Super Contributor
timestamp: July 10, 2016, 04:40:38 am
content: The 34063 is a switch mode converter buy from disty or you might get surprised.Also, you should check down the line and see if there are any other shorts or bulged caps. The converter blew for a reason. I would also change every electrolytic just because they're usually the crappiest thing that can be had on low end products.Good luck.

author: true
author_rank: Frequent Contributor
timestamp: July 20, 2016, 12:48:44 am
content: Or... pick up a cheap gigabit switch.If you just want to practice repair go for it, but based on your flag, it's probably not economical nor helpful unless you desperately need a 10/100 switch...
Please help me spectrum analyzer aeroflex ifr 2397 YIG Cal : Fail - Page 1
Forum section: electronics / repair

author: phunhi
author_rank: Newbie
timestamp: April 06, 2016, 08:41:01 am
content: I have a spectrum analyzer aeroflex ifr 2397, now it has a problem:- When I power ON, System Alignment Result : Yig Cal : Fail and it crashes..Anyone have the same problem please help me.Thanks very much.

author: nfhiggs
author_rank: Newbie
timestamp: July 19, 2016, 06:18:41 pm
content: The reference YIG oscillator has failed. You will most likely have to send it to IFR for repairs.

author: CJay
author_rank: Super Contributor
timestamp: July 19, 2016, 06:54:28 pm
content: Quote from: nfhiggs on July 19, 2016, 06:18:41 pmThat's it?No possibility of a missing voltage, bad connection, bad driver, PLL or anything else?

author: jkf1000
author_rank: Regular Contributor
timestamp: July 19, 2016, 06:54:49 pm
content: What checks have you done so far, have you checked any power supply rails, do you have any service material/schematics? Karl

author: nfhiggs
author_rank: Newbie
timestamp: July 19, 2016, 06:56:07 pm
content: If you can find a scrap unit with a functional Reference Oscillator you may be able to repair it. These kinds of oscillators are usually temp stabilized, sealed units.
JBL MPX1200 repair due to stupidity. Have a look at this wiring. - Page 1
Forum section: electronics / repair

author: Anks
author_rank: Frequent Contributor
timestamp: July 19, 2016, 03:48:09 pm
content: Just looking at a JBL mpx1200. Well this is how the plug was wired up. Not had a proper think about this yet to think if it would damage the unit or check even if it still works. This is the second plug wired wrong this week. The last one had live connected to the earth pin.

author: WackyGerman
author_rank: Regular Contributor
timestamp: July 19, 2016, 04:28:46 pm
content: If you earth the board on the other side you safe solder . It is called spot welding then

author: SeanB
author_rank: Super Contributor
timestamp: July 19, 2016, 05:58:19 pm
content: Looks like it was wired up by somebody who had as the only tool to do it a single dull edged kitchen knife. Hacked the insulation on both sleeving and the inner cores, and it looks like they chewed on the wiring as well.

author: CJay
author_rank: Super Contributor
timestamp: July 19, 2016, 06:08:52 pm
content: Quote from: Anks on July 19, 2016, 03:48:09 pmUgh, used to get those all the time, first job, always, when something has a rewireable plug was to check the the wiring of it and then fit a new plug if it wasn't shrouded
Rigol 1022U fried output - Page 1
Forum section: electronics / repair

author: oleksiy
author_rank: Newbie
timestamp: July 05, 2016, 03:41:25 pm
content: hi Guys,recently fried my Rigol 1022 by mistakenly applying high voltage on one of its inputs. close board inspection showed one component with sign of smoke and damage. unfortunately it has label sanded off, giving me hard time to find replacement.. can someone help me identify it ?on photo I have I component (choke) unsoldered which was shortened

author: Kleinstein
author_rank: Super Contributor
timestamp: July 05, 2016, 04:56:13 pm
content: From the circuit around the 8 pin chip, this is a single OP in SO8 case. It's driving a 50 Ohms output, so it might need to be a slightly more powerful OP.

author: oleksiy
author_rank: Newbie
timestamp: July 05, 2016, 05:08:28 pm
content: thank you, Kleinsteinon other post here I just found same issue people reported:https://www.eevblog.com/forum/repair/rigol-dg1022-attempted-repair-(and-reverse-engineering)/msg950961/#msg950961it's seems like this is THS3095.. I will go ahead and order it..also if someone knows where/how I may get replacement for unsoldered component , which might be faulty choke. does anyone have any experience with it ?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 05, 2016, 07:56:50 pm
content: The de-soldered ouput filter looks like a current compensated common mode choke, or a kind of 1:1 transformer. AT least this would make sense from the circuit. As the inductance can be rather low (e.g. 1 µH range) this might very much look like two shorts. Its only a problem it all 4 contacts a connected somehow.For a test one could use two wires through one ferrite bead.

author: oleksiy
author_rank: Newbie
timestamp: July 05, 2016, 09:25:13 pm
content: Kleinstein, you absolutely right..I just made picture of cracked unit and counted number of loops.. (12 loops in one row)based on original dimensions it might be ACM4532http://www1.futureelectronics.com/doc/TDK/ACM3225-271-2P-T001.pdfif I go with ACM4532 (800 Ohm OR 600 Ohm impedance) will it make big difference ?(same data found onhttp://www.mikrocontroller.net/topic/203503)

author: oleksiy
author_rank: Newbie
timestamp: July 18, 2016, 10:50:24 pm
content: hi guys,just in case it's interesting to anyone.. I ordered THS3095D and installed it..after I power-up signal generator and set it to any other amplitude above 2v on channel 1 it says "protection overload" and disable channel..however, if amplitude is 1v on low frequency (300mHz)--> if i measure output on channel 1 it swings from 0.57 to -0.61 volts..channel 2 has also little difference between shown amplitude and actual voltage..it seems like THS3095D is not the right opamp for 1022U ?

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: July 18, 2016, 11:13:33 pm
content: Is that a burnt trace to the right of the removed choke?Also, the TL082C looks like it might be damaged but it could also be fallout from nearby burnt parts.Look at the part next to J801, it appears that it could have issues based on the solder joints.
Yet another Fluke 8842A transformer solder fail - Page 1
Forum section: electronics / repair

author: LazyJack
author_rank: Frequent Contributor
timestamp: July 19, 2016, 11:20:07 am
content: Couldn't resist to get a cheap Fluke 8842A from eBay. It was advertised as powering up, without the display. Since it was loaded with the AC and GBIP options and was in a very nice physical condition, I figured, even if it is very dead, I would able to source an other instrument and make one from the two, with all the options.I first looked into it, did not see any visibly obvious, so tried powering up. The relays clicked and they also clicked when changing ranges, so at least for some extent it was working, but no display at all.Components had 1988 datecodes, so it's not exactly young, but at least not older than me.Next step is to check voltages. They all looked ok on the main board, except the VFD filament voltage, which should have been 4.5VAC, but was zero.OK, so the first usual suspect, the transformer. pins 14-16 are the filament, and bingo! As soon as nudging it with the probe, the display flashed.Lets get the soldering iron and resolder all pins. It was really hard to do, once reflowed the solder, on some pins it actually separated from the lead, was not wetting at all. Remove solder, srape pins, it was now possible to properly wet and solder.Turn on, display works, all self tests are passed. Fortunately the VFD is of good brightness (not on the picture, because of the flash), the instrument is pretty clean and tidy inside an outside.I'll need to check the accuracy, but first checks show it is not way off at least.I am satisfied and happy.

author: mzacharias
author_rank: Frequent Contributor
timestamp: July 19, 2016, 12:26:09 pm
content: My 8840A - virtually same story. Often the bad solder connections are hard to tell visually. Common problem, I guess.

author: LazyJack
author_rank: Frequent Contributor
timestamp: July 19, 2016, 06:46:06 pm
content: All right. I tested all functions and ranges and pretty much matches up to the Fluke 87. Of course this should be done the other way around, but I don't have anything more precise than the 8842A. But at least it shows that functions work and they are likely very close (maybe even in) to being in spec.The GPIB also works, so it's now possible for me to set up long time measurements and data acquisition.The ultra high input impedance voltage ranges are also pretty cool. Really nice instrument.I think it was worth the 70 bucks.

author: lowimpedance
author_rank: Super Contributor
timestamp: July 20, 2016, 12:38:08 am
content: Good score for 70 bucks,...... perhaps this thread could have been just an addition to this one.https://www.eevblog.com/forum/repair/what-was-your-easiest-repair-ever/Still always good to see good old gear being saved from landfill..........enjoy.
Repair of Marconi 2305 modulation meter (again) - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 17, 2016, 11:09:13 am
content: My Marconi meter died again, this time it was due to a shorted IC dragging down the 5v supply.Video of the repair is shown here:https://youtu.be/62m3swoPy2Q
How to choose a SCR - restoring BK Precision 1601 and 1602 - Page 1
Forum section: electronics / repair

author: dlucy67
author_rank: Contributor
timestamp: July 27, 2016, 10:43:20 pm
content: I'm restoring two power supplies, one a low voltage DC and the other a high voltage DC unit, and the schematics indicate a SCR but do not provide enough detail to find a suitable replacement. Both units' SCRs are TO-92 packages, they both have "1810" markings, but I have not found any datasheet, specs or crossref online.How should I choose a replacement SCR based on the circuit parameters and the SCR's application?

author: singapol
author_rank: Frequent Contributor
timestamp: July 28, 2016, 05:19:56 am
content: Quote from: dlucy67 on July 27, 2016, 10:43:20 pmIn the abscense of correct/exact scr data I think you have to try by circuit parameters and scr applicaction.Just make sure pin out is identical or legs can be oriented to fit pcb connections.Attached link of suitable to92 package scr:http://www.futurlec.com/DiodesSCR.shtml
Lenovo B570 laptop optical drive problems - Page 1
Forum section: electronics / repair

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 16, 2016, 06:27:32 pm
content: Symptom: Barely ever recognizes disc. Many different discs that play fine in my stand-alone player. Cleaned the discs, cleaned the lens. Same result.OS: Win 7Drive: TSSTCorp CDDVDW TS-L633FFirmware: LE02Player software: VLCTried all the standard "troubleshooting", nothing. There's no malware on the PC, no driver issues. I tried to find new firmware for the drive but by the code it's a Lenovo special, nothing I could find.Is it possible to know what the stupid drive is doing so I know where it fails? Can I find out the optical power the block is putting out with software?I installed Opti Drive Control, but it gives high level info. It just says "insert disc"!when I ask for a test, it seems to want to test the disc, I want to test the drive!So eventually after rebooting the PC and inserting the disc a few dozen times it eventually sees the disc and plays fine. Even when it plays "fine" it trips up on slightly scratched discs.The thing is ancient (2011) so all I could find were pulled spare drives.Yes I still use DVDs, I get to watch tons of stuff from the library! O0 Uh, when it works, that is...

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2016, 06:35:49 pm
content: Just buy a drive. Like.. any drive. They're pretty standard, just pop the faceplate on. Just don't buy any thing from TSST, they're universally junk.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 16, 2016, 06:38:01 pm
content: in a laptop? They're all the same? OK, I'll look around. And yes, I can see that TSST is pretty junky...

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2016, 06:54:08 pm
content: I believe that's a SATA drive, so yes, they're standard. I doubt Lenovo used a special connector (I think I have a B570.. I'll have a look).The only trouble may be with the faceplate, but usually they're fairly compatible.
What's this connector?  - Page 1
Forum section: electronics / repair

author: iXod
author_rank: Frequent Contributor
timestamp: July 16, 2016, 07:29:25 am
content: Anyone recognize this?3-pinspin diam: 0.6 mm / 0.235 inpin spacing: 8.85 mm / 0.15 inI need the matching housing and 3 pins. Photos of the female assembly are from a video, not in my possession.Thanks.

author: iXod
author_rank: Frequent Contributor
timestamp: July 16, 2016, 07:37:15 am
content: Thanks for your reply blue."Dupont cable"? Never heard of that. I presume you mean just a bare 0.1" female soldered/crimped to wire and shrinked? Times 3, of course.Only if I can't come up with a mating connector...Cheers.
Tektronix 5006 DC power - Page 1
Forum section: electronics / repair

author: tonyc
author_rank: Newbie
timestamp: July 14, 2016, 09:29:53 pm
content: My 5006 stopped working a couple of weeks ago. When I turn the power switch on I still hear the beep sound but no DC power come out of the slots. I know the AC power is good because the DMM module uses AC power and still works. Does anybody know what are the usual culprits for such problem?

author: BFX
author_rank: Frequent Contributor
timestamp: July 15, 2016, 07:21:37 pm
content: I think you really need take apart this guy and measure somethingA few photos will be helpful

author: David Hess
author_rank: Super Contributor
timestamp: July 15, 2016, 08:48:56 pm
content: In the TM5006, the DC power is provided by a switching power supply while the AC comes from a line transformer. Obviously there is a problem with the switching power supply; the primary suspect is the aluminum electrolytic capacitors which are probably worn out with age.There is no beeper so I assume the beep is coming from the switching power supply when it tries to start.
Help with finding the correct Value for a Capacitor - Page 1
Forum section: electronics / repair

author: ewoewo
author_rank: Newbie
timestamp: July 15, 2016, 06:07:15 pm
content: Hi,in this transistor vintage guitar amp "novanex 20 automatic" there are lots of these Capacitorsand I am afraid their value isnt 2 pF because of their case size (100V).Can someone help me to find the right value (The IC is on the picture forthe size comparison only)? Id wanted to replace them with similar ones.Thanks, Erwin

author: Andy Watson
author_rank: Super Contributor
timestamp: July 15, 2016, 06:18:53 pm
content: 220nF, 250V, 10%(The red band at the top should be interpreted as two red bands).http://www.electronics-tutorials.ws/capacitor/cap_5.html

author: BFX
author_rank: Frequent Contributor
timestamp: July 15, 2016, 06:22:54 pm
content: or try this explanationhttp://www.electroschematics.com/5713/colour-coded-capacitor/

author: ewoewo
author_rank: Newbie
timestamp: July 15, 2016, 06:25:23 pm
content: Thanks that Info did it!
Tektronix AFG2012 function/arb generator - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: July 14, 2016, 06:12:10 pm
content: Just got this off Ebay. Took a few pictures of the internals.Jay

author: Jwalling
author_rank: Unknown
timestamp: July 14, 2016, 06:13:47 pm
content: Goodness! Is that a PCI connector I see ?I think so...Works great!Jay
equivalent transistor - Page 1
Forum section: electronics / repair

author: mohandes
author_rank: Contributor
timestamp: July 13, 2016, 02:44:43 pm
content: himcr100-6 is burn.can i use c106M???regards

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 13, 2016, 04:39:58 pm
content: Probably good enough.

author: mohandes
author_rank: Contributor
timestamp: July 14, 2016, 12:29:33 pm
content: Quote from: T3sl4co1l on July 13, 2016, 04:39:58 pmok i use it
Toshiba TV backlight troubleshooting - Page 1
Forum section: electronics / repair

author: eugenenine
author_rank: Frequent Contributor
timestamp: July 13, 2016, 10:35:25 pm
content: I am troubleshooting our old TV, a Toshiba 32hlc56 with no backlight. I have replaced laptop backlight tubes before so when I found that I could see a dim image by shining a light on it I figured the same, a burned out bulb. However I opened this and found 8 of them which told me I have a much greater chance of a power supply issue. I did some searching and found a badcaps.net which says some tvs/monitors if one bulb burns out the inverter shuts down and they typically troubleshoot with a spare bulb.I don't have any spare bulbs so I'm wondering if I can troubleshoot in another way.First does anyone have any info on these, what voltage should I see from the power supply to the backlight inverter boardsecond can anyone confirm this is the case with this model (or Toshiba's in general),will one lamp shut them all down?

author: Kilrah
author_rank: Unknown
timestamp: July 13, 2016, 10:48:11 pm
content: Measuring the voltage on a CCFL backlight without an HV probe is not a very good idea, especially if something causes it to run without a load.IMO shorting the tubes one after the other would be a wiser thing to do, hopefully can help you find the broken one.

author: eugenenine
author_rank: Frequent Contributor
timestamp: July 13, 2016, 11:09:06 pm
content: I was going to measure between the power supply and the hv inverter board, wanted to make sure I have low voltage power there first.I didn't think about shorting one tube at a time, good idea, I'll try it.

author: BMack
author_rank: Regular Contributor
timestamp: July 14, 2016, 07:28:23 am
content: Power supply should output 24v to the inverter. If the voltage is not there or is low, disconnect the inverter and try again. If there is no voltage, the power supply is likely bad. If the inverter kills the 24v, it's either the inverter or the panel. If the voltage is low and fluctuating, it's the power supply.You might also need to check back light on(bl_on) coming from the main board, should be 3.3v or 5v.
Help identifying these components - Page 1
Forum section: electronics / repair

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: July 13, 2016, 11:49:26 pm
content: Hi Guys. I have three bad components on a board I am working on. I believe that they are all mosfets because they drive small brushed motors. I tried googling almost every combination but no luck. Please take a look at the picture and if anyone can help me out I surely appreciated it.Thanks for any help.Fluxed

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 14, 2016, 12:25:20 am
content: Maybehttp://www.vishay.com/docs/65701/si2300ds.pdf?They are all probably intended to be the same. Looks like the board has been reworked before.

author: olliisit
author_rank: Newbie
timestamp: July 14, 2016, 08:36:42 pm
content: Without Warranty:AC9T : Si2310 (Tuofeng Semic.)2300: Si2300,GM2301 (Vishay,++)AISHB: Si2301(DS) (different Chinese Companys)
Yamaha DX 7 overheated and no sound - Page 1
Forum section: electronics / repair

author: thomastorm
author_rank: Newbie
timestamp: July 10, 2016, 08:32:27 am
content: Hi everybodyI forgot to switch off my DX 7 for days and i found it overheated and with no sound.What can i do now?Thanx

author: Totalsolutions
author_rank: Contributor
timestamp: July 11, 2016, 08:35:30 am
content: Hi, Mk II .... ? Not much to go on. Have you checked the PSU (power supply unit), if its that old a keyboard and has a external power brick more likely the transformer overheated only, open circuit to the internal thermal fuse.Sent from my GT-N7100 using Tapatalk

author: Totalsolutions
author_rank: Contributor
timestamp: July 11, 2016, 08:39:08 am
content: Check out youtube user "fredturd" Yamaha DX 7 Battery Repair Tips #1Sent from my GT-N7100 using Tapatalk

author: Jr460
author_rank: Regular Contributor
timestamp: July 11, 2016, 11:02:18 pm
content: Is this a DX7 or the DX7IID/DX7IIFD?Years ago I had my 1987 DX7IID go dead. Power supply was the issue. The local repair shop really didn't want to touch it but said most likely the big 5W resistor in PS opened up, it was a common fault. The supply is internal, a separate module from everything else in t he unit. Even the original DX7 didn't use a wall wart/plug pack.Opened it up, measured, and sure it was open. I forget the value of it, something like 2.5 Ohms 5W. I could find that exactly but found to resistors at 5W that paralleled was very close to the value I needed. Whacked it in, and it has been working fine for the past 15 years or more.

author: bitseeker
author_rank: Super Contributor
timestamp: July 12, 2016, 01:59:22 am
content: Correct, internal power supply. That's the best place to start the investigation on most dead devices, keyboards included.
BK Precision 2800 LED DMM from 1976 - replacement for 75491? - Page 1
Forum section: electronics / repair

author: Photon939
author_rank: Regular Contributor
timestamp: July 05, 2016, 09:14:52 pm
content: I picked up a rather sad and dirty looking BK Precision 2800 meter at a local hamfest for $2 on Saturday. After going to the store for some C cell batteries it seems to power up; the main IC seems to be ok but the two rightmost digits do not work.From google images, mine is significantly dirtierData into IC4 (75491) looks good, but there seems to only be a bit of sawtooth shaped ripple on the output pins. Bypassing the output pins with a 1K resistor to ground causes the respective LED display to glow so the displays are OK.There is currently one guy on ebay in the US selling NOS Radioshack Archer branded 75491 chips, everything else is probably counterfeit junk from china. I would rather not pay nearly $10 for an IC if a modern chip is available with the same pinout.I will post images and some waveform shots once I get home.Thanks in advance

author: lowimpedance
author_rank: Super Contributor
timestamp: July 06, 2016, 01:49:47 am
content: A quick look reveals nothing pin for pin compatable with the 75491.The 'closest' internal functionaly speaking is the UL200x series, BUT not pin for pin and also has common emitters (and 6 drivers not 4)www.diodes.com/_files/datasheets/ULN200xA.pdfSo if fixing the meter is something you must do (dont we all like a challenge!) then perhaps you could 'shoe horn' one of the UL types in , although I have not looked at the 2800 circuits to see if its feasible.Ultimately the $10 NOS part may be the easiest and cheapest option.Good luck

author: Photon939
author_rank: Regular Contributor
timestamp: July 08, 2016, 02:40:13 am
content: Thanks, I guess if I cant find any others I'll fork out the bucks for the NOS Archer part.Here's a photo of the guts:

author: Kleinstein
author_rank: Super Contributor
timestamp: July 08, 2016, 11:56:07 am
content: Functionally there is a chance to use just 4 FETs like 2N7000 to replace the function of the chip, if it is just switching to GND. At least one could try with 1 digit.

author: JFJ
author_rank: Regular Contributor
timestamp: July 08, 2016, 12:19:12 pm
content: Quote from: Photon939 on July 05, 2016, 09:14:52 pmAn eBay seller in the UK has a small quantity of SN75491N IC's listed that don't appear to be the unbranded version from China:http://www.ebay.com/itm/SN75491N-/361618441090

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: July 10, 2016, 09:56:14 pm
content: Pretty slick meter. Gotta love LEDs.
Repair-Hint: Subwoofer Canton AS-10 "no sound" - Page 1
Forum section: electronics / repair

author: HummingBird
author_rank: Contributor
timestamp: July 10, 2016, 09:26:24 pm
content: ...if your AS10 is not playing any more (or disturbing the neighbours), pls check if the stereo pot for the frequency control is high-impedance...thats an series error in that sub. Replacement is available on ebay but hard to install, I mounted it upside-down with some wires. Best regards tp your neighbours. Maybe just shortcut it for testing (see pic).Sincerly yours, HB.
Looking for JOBO Autolab ATL-1 Service Manual - Page 1
Forum section: electronics / repair

author: ElektroQuark
author_rank: Unknown
timestamp: July 22, 2016, 09:02:59 am
content: I know this is complicated but I have to try.Anyone has a copy of the JOBO Autolab ATL-1 or AT1 head?

author: ElektroQuark
author_rank: Unknown
timestamp: July 22, 2016, 11:35:45 am
content: All those resources are checked. I emailed involved APUG forum users too.Now trying here, a long shot. Let's see. The Service Manual exists, in paper (it's from 1984), I have only to find someone willing to copy or sell it.The Autolab has some issues, that I have solved, but new ones arise as it steps in its next work functions.

author: Falkra
author_rank: Regular Contributor
timestamp: July 22, 2016, 04:50:43 pm
content: Here are some service manuals for all other models (sorry), in case they share parts with ATL-1 :http://luigipasto.com/pages/resources/hoping this can help although it is not what you are looking for.
trying to find "LT1155" datasheet? - Page 1
Forum section: electronics / repair

author: Eliminateur
author_rank: Regular Contributor
timestamp: July 09, 2016, 07:38:36 pm
content: Hello,i have a problematic glowplug preheater module that i'm trying to reverse-engineer to see the problem it has and i find a Linear tech. 8-pin SMD dual mosfet driver(it is after all driving two mosfets independently) that i can't find ANY info!.chip has the LT logo then 525 and below it "1155I" (or it could be a lowercase L)all i can find is the LT1158 which is a half-bridge driver to load a single load, but in this one each mosfet is driving a separate bank of glowplugs

author: Ian.M
author_rank: Super Contributor
timestamp: July 09, 2016, 07:44:08 pm
content: Could it beLTC1155?

author: Eliminateur
author_rank: Regular Contributor
timestamp: July 09, 2016, 07:56:16 pm
content: Quote from: Ian.M on July 09, 2016, 07:44:08 pmdoh!, i forgot that LT also had LTC in the name, y'know what, it does look like the correct chip eyeballing the PCB, there are some differences as it's not driving the gate directly(it has some sort of network of transistors or diodes in those sot23 unreadable packages) and there are no current sense resistors(it's driving blind, it's only sampling voltage output).gah why couldn't they stick to the reference design!
GT-006 digital amplifier. Shorted 5v rail... - Page 1
Forum section: electronics / repair

author: Rytikar
author_rank: Newbie
timestamp: July 09, 2016, 02:32:33 pm
content: Hi everybody!I read an article about how to build your own bluetooth transportable speaker system. I had a set of speakers and a Dayton DAT-100 amplifier lying around, so I got myself a bluetooth receiver and got to work.To have only one power (24V) input, I thought it a good idea to open the amp, find the 5V rail and use it to supply the bluetooth adapter. That worked well when tested all disassembled, so I built everything into the speaker and......I shorted the 5V rail because I had not enough clearance from my soldering to the aluminium cabinet... Thing is dead, Jim...Power LED still comes on, 24V can be traced trough the system.As far as I can see, 24V is not reaching the power converter though (three pin, but no label on it). Obviously no 5V either.I've not tested the converter yet, as it does not get 24V.Any ideas where to look at (newbie)?Thanks in advance
Yaesu FT 101 pre-repair checkout - Page 1
Forum section: electronics / repair

author: Shock
author_rank: Super Contributor
timestamp: July 09, 2016, 03:35:22 am
content: Good video showing pre-repair checkout of a modular radio.Covers checking out supply rails before powering up, relay cleaning and a few common issues of aging equipment.

author: Towger
author_rank: Super Contributor
timestamp: July 09, 2016, 07:52:59 am
content: I am not sure if I missed a bit, but I take it the origional audio board with the bad caps was replaced with an older version. Looks as if the rig was used as a donor, never a good sign.

author: Len
author_rank: Frequent Contributor
timestamp: July 09, 2016, 02:16:36 pm
content: Radio Tech already started a thread about his video here:https://www.eevblog.com/forum/rf-microwave/59-yaesu-ft-101-series-part-1-preliminary-test/
PS4 blue blinking pulsing light (BLOD) no video - Page 1
Forum section: electronics / repair

author: poot36
author_rank: Frequent Contributor
timestamp: July 08, 2016, 04:11:12 am
content: I just got a broken PS4 that when it is turned on all it does is blink the power light blue and there is no video output. I can confirm that the power supply is good and that the hard drive is working. I also know that if the APU does not get enough cooling the PS4 will beep 3 times and shut down very quickly after trying to power on. So I think the thermal sensor is working correctly as well. I have tried what I call a low temp reflow (200C) to just reflow the joints that connect the die to the PCB carrier not the actual motherboard and that did not work. My heat gun is one of the 700W China SMD rework ones combined with a soldering iron. I don't think that it will be powerful enough to reflow the entire APU. Would it work if I found a way to preheat the board to 150C or so or would I have to preheat the board to a higher temperature? Or is the problem not the APU at all but the HDMI chip or the standby low power processer chip?

author: Rasz
author_rank: Super Contributor
timestamp: July 09, 2016, 12:03:41 am
content: sure, you need to bake it, all of it (case included)set oven to 400'C and leave board for at least 15 minutes

author: poot36
author_rank: Frequent Contributor
timestamp: July 09, 2016, 02:53:35 am
content: I have tried the oven trick on other PCBs and have not had great success. I got the PS4 for almost free so I would kind of like to fix it. I am thinking of getting one of the IR hotplates and placing that under the APU and then using my heat gun on the top with some flux. Does this seem like a good idea?
Creative Nomad Jukebox doesn't turn on - Page 1
Forum section: electronics / repair

author: sony mavica
author_rank: Frequent Contributor
timestamp: July 09, 2016, 01:13:44 am
content: so i decided to sell my my portable cd player boombox the other day as i hardly listen to cds anymorethen as im looking online i see a person selling a like new Creative Nomad Jukebox 10gb for $10 $4 for shippingthey say its working 100% fine they have 1995 good feedback no bad feedback so i beveled them when they said its workingbut when i put 4x AA in it and press the play button on hold it down the device will not turn on even if i plug the power cable in i did try pushing the reset button with no luck and the hold switch is not onis there any other things i can try before i email the seller?

author: Seekonk
author_rank: Super Contributor
timestamp: July 09, 2016, 02:21:15 am
content: Nothing that is easy. I have some things that have not been used in a while and the contact surfaces corrode under the tactile rubber and snap metal switches. Cleaning them brings the units back to life.
DTV60 scope ground level unstable - Page 1
Forum section: electronics / repair

author: mhilton2013
author_rank: Newbie
timestamp: July 02, 2016, 10:58:54 pm
content: Hi, this is my first post on the EEVblog forums. Hopefully my next one will be more useful to others.I recently acquired a Farnell DTV60 scope but it has an issue with the Y axis. The ground level doesn't seem to be stable but moves up and down slightly and sometimes goes off the CRT entirely for a short while. This can be observing when the channels are set to ground, DC or AC. Interestingly it seems to affect channel one more than channel two. Also I now recall that it would make a short sizzling noise on occasion when powered up. I looked inside the scope and I can't see any visible damage apart from a little leakage on the power supply's capacitors. I'm new to repairing test equipment so any pointers as to where the fault could possibly be would be greatly appreciated.

author: tggzzz
author_rank: Super Contributor
timestamp: July 02, 2016, 11:18:15 pm
content: PSU capacitors are a frequent source of problems.Google for the scope's manual, and replace the electrolytics with new equivalents.Rules of thumbfor aluminium electrolytics and tantalum beads are to ensure the rated voltage is double the working voltage, and for aluminium electrolytics that the capacitance is doubled. If it is a switching PSU, get a capacitor rated designed for switching PSUs, e.g. Nichicon PW series.There are many threads on this topic.

author: mhilton2013
author_rank: Newbie
timestamp: July 03, 2016, 11:22:45 am
content: Ok thanks, I'll see if I can get new caps for the PSU. I made another observation today that it seems to work fine without any issues at all for about 5 mins, then it starts bouncing around the place.I'll post back when I have changed the caps, though it may be some time. Thanks

author: mhilton2013
author_rank: Newbie
timestamp: July 08, 2016, 03:50:48 pm
content: I haven't got my soldering iron back yet so I haven't been able to replace the PSU caps but I found the circuit diagrams and probed the power rails and they seem very stable even when the oscilloscope is malfunctioning. I seem to be able to cause the trace to start bouncing around by giving the oscilloscope a sharp knock.It's particularly annoying how this thing is impossible to take apart without desoldering lots of bodge jobs. Could it be something loose thats getting knocked about? CRT kaput?
Separating/removing the ceramic layer from the heatsink on Tektronix hybrids - Page 1
Forum section: electronics / repair

author: mrnuke
author_rank: Regular Contributor
timestamp: June 26, 2016, 10:55:21 pm
content: I'm referring specifically to the hybrids in the 2400 series analog scopes. Has anyone tried this? I'm thinking of replacing the ceramic with a PCB rather than blindly seek undiscovered pockets on Unobtainium.I've tried heating it up with a heatgun, but the ceramic won't budge. I want to do this while preserving both the heatsink and ceramic.

author: mrnuke
author_rank: Regular Contributor
timestamp: July 08, 2016, 12:04:38 am
content: Finally did it! The secret is to prop up the heatsink on some helping hands. Set the heat gun to max heat, max air, no nozzle.Then, with one hand and a set of pliers, hold the heatsink in place, while with the other hand and another set of pliers, wiggle the ceramic until it comes off. The glue is very sticky and gummy.

author: chihaxinh
author_rank: Regular Contributor
timestamp: July 08, 2016, 01:39:11 am
content: Why you need remove ceramic layer ? I have one Tektronix 2440 but running quite hot and fail in high frequency

author: mrnuke
author_rank: Regular Contributor
timestamp: July 08, 2016, 06:45:22 pm
content: Quote from: chihaxinh on July 08, 2016, 01:39:11 amIt will all become clear in a few weeks.
Miele Control Board - Identify Power Supply IC - Page 1
Forum section: electronics / repair

author: Lion_Tamer
author_rank: Contributor
timestamp: February 04, 2016, 10:17:08 pm
content: Hi AllI am trying to mend a control board for a washing machine where the power supply IC has blown but as yet I have not been able to identify it and wondered whether the vast knowledge and wisdom of the community here could help.The details that I can make out of the chip are:Make: Philips SemiconductorPackage: 14 Pin SoicLine 1: ....2TLine 2: ....935Line 3: ....052The board dates from around 2005/2006 era, I don't yet know why the chip failed but it is the only visually blown component, there is also a fusible resistor in the power feed to it that is OC.The circuit layout around the chip appears to be this:Pin 1: Decoupling capacitor to ground? also feeds into a couple of transistor?Pin 2: GroundPin 3: GroundPin 4: GroundPin 5: GroundPin 6: Parallel Resistor and Capacitor to GroundPin 7: Parallel Resistor and Capacitor to Ground, also feeds into a couple of transistors?Pin 8: Resistor to low voltage positivePin 9: GroundPin 10: GroundPin 11: 1 Ohm Sense resistor to groundPin 12: Not ConnectedPin 13: Not connectedPin 14: Transformer WindingThank youJem

author: rich
author_rank: Frequent Contributor
timestamp: February 05, 2016, 01:59:33 am
content: very wild guess:http://www.farnell.com/datasheets/60405.pdf

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 05, 2016, 03:25:39 am
content: Looks very plausible. TEA1522T. Pinout seems to match.

author: RichENZED
author_rank: Newbie
timestamp: July 08, 2016, 01:59:40 am
content: Can I ask how you got on in the end?I tried once in the past.I had an exploded TEA1522t and bought a replacement from eBay.Mine turned on but there was another fault where the water inlet valve operated continuously.Did you have better luck?
Keithley 2110 DMM - Error codes 603 and 607 - Page 1
Forum section: electronics / repair

author: cio74
author_rank: Regular Contributor
timestamp: July 05, 2016, 02:55:28 pm
content: Hello,I have an issue with this Keighley meter, it does not pass self test and also seems not to care if the leads are attached and connected to anything, very little difference to the actual readings.Test Error1. Err 6032. Err 607I have found this manual with codeshttp://instrumentationlab.berkeley.edu/sites/default/files/BSC01/Keithley-DMM_2110.pdfpage 180603 Front-End MCU does not respond The main CPU U1601 attempts to establish serial communications with the front-end processor U2001. Communication must function in both directions for this test to pass.607 Buffer1 offset out of range This procedure is to test the offset of buffer U507. The result is checked against a limit of 0 ± 0.1 mVHere is a video of the unit with no leads attached and a jumpy displayAny idea what could have caused it? It is basically new, just opened although calibration back in 2013 and just shelved since then.Thanks.Cio

author: cio74
author_rank: Regular Contributor
timestamp: July 07, 2016, 07:31:41 am
content: no reply, is it really a lost cause?...

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: July 07, 2016, 08:52:18 am
content: Without an schematic of the unit, I couldn't find any on Google it's difficult to know the path to follow.You could try to buy a service manual for the 2110 with the schematic of the DMM, and follow the path from U1601 to U2001 to see if there is any blow up part, or voltages not present.Since U1601 is trying to establish two way comm with U2001, something must be failing along this path.And the 607 can be appearing because of the 603.Without schematic will be reverse engineering, following the path.

author: cio74
author_rank: Regular Contributor
timestamp: July 07, 2016, 03:33:09 pm
content: I don't know where to buy the service manual from.I had the cover removed in a hope it may be some sort of lose connector or obvious defect but everything looks untouched.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: July 07, 2016, 07:22:32 pm
content: Keithley 2110 (Picotest M3510A) is based on the Keithley 2000 schematics.

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: July 07, 2016, 08:27:14 pm
content: If the 2110 is base on the 2000, the schematic of the 2000 is available on xdevs.com, TiN website, you could check there and try to see if you can follow the path.I see a lot resemblances in there with my 2000.
[Solved]Subwoofer Amplifier Voltage Problem? - Page 1
Forum section: electronics / repair

author: dundee
author_rank: Regular Contributor
timestamp: July 08, 2016, 01:30:48 pm
content: Hi Guys!I'm trying to repair a Active Subwoofer.I found a shorted TL074 on the input Filter board:After replacement of the TL074 the subwoofer worked very well for 30 minutes. Same issue --> TL074 shorted.I measured +-20V on the voltage rails and thought everything is ok.Later i found the schematic for the power supply and amplifier:Specified were +-15VI'm not really sure what's going on. I tested Q501, Q502, Q503 and all resistors around them.Changed Caps C505, C507, C507, C508 and the Z-Diode. I noticed that R501 and R502 get really hot.Would be nice, if someone has a tip for me.

author: uncle_bob
author_rank: Unknown
timestamp: July 08, 2016, 01:40:14 pm
content: HiWhat is the voltage on the zener? It should be about 16V. If it's not then the new diode is blown. If it is, what is the voltage on the pass transistor's emitter (we already know it's 20V). Pass transistor Q501 has 16V on the base and 20V on the emitter ... pass transistor is fried. It may be fried as a short and takes out the zener each time you replace it. Good bet that the speaker got an over voltage event at some point (or just plain got run to hot). I'd replace both pass transistors.Bob

author: MosherIV
author_rank: Super Contributor
timestamp: July 08, 2016, 04:00:36 pm
content: QuoteNothing to be worried about (unless they are glowing !).It looks like they are being used as high side current shunts (current monitor) as part of some kind of transistor/zener diode driven linear regulator circuit.

author: Anks
author_rank: Frequent Contributor
timestamp: July 08, 2016, 10:12:54 pm
content: Power supply is killing the opamp. Its being used in a situation were it is susceptible. Put some resistors inline with the supply. you could also measure the current over them with a scope. if its going into oscillation then its pulling current to produce sound way over the cut off point of the filter.regardless more likely a bad cap.

author: dundee
author_rank: Regular Contributor
timestamp: July 10, 2016, 11:43:27 pm
content: I got it!TIP31 and TIP32 were exchangedMust be a mistake of the manufacturer because i bought it cheap from a B-Stock.Great support, thank you!