hybridfree/eevblog-posts huggingface dataset:
Atten AT-860D Heavy Duty 600W - Page 1
Forum section: electronics / repair

author: trigger-99
author_rank: Newbie
timestamp: October 16, 2016, 08:41:30 am
content: hi dose anyone no if this is any goodhttp://www.ebay.co.uk/itm/Atten-AT-860D-Heavy-Duty-600W-Digital-Hot-Air-Station-SMD-Rework-/121955808034?hash=item1c6521f322:g:e~IAAOSwv~xXD0z-as i'm lucking for a new one that works for bga removal i have the aoyue 968 and it sucks for thermal mass i would buy the HAKKO FR810B but dont have £400 any info on AT-860d station would help
Sony STR-DA3300ES AV receiver repair - Page 1
Forum section: electronics / repair

author: android
author_rank: Regular Contributor
timestamp: October 15, 2016, 11:42:08 am
content: I'm having a go at repairing this AV receiver for a friend. So far I've replaced a pair of blown darlington transistors (Sanken MN2488 & MP1620) on the surround right channel, but have today found a couple of 100resistors are bad too on that channel (one is slightly off spec, and the other is open circuit).Easy...except that theservice manualsays that these resistors should be "nonflammable" for safety reasons - but I can't seem to find any from RS or Element14 etc that are marked "nonflammable".Is there another keyword or attribute that I should be looking for? (Or should I just replace them with 1/2W standard resistors)

author: singapol
author_rank: Frequent Contributor
timestamp: October 15, 2016, 06:40:45 pm
content: QuoteTry fusible resistors.
home theater problem no music! - Page 1
Forum section: electronics / repair

author: christos
author_rank: Regular Contributor
timestamp: October 13, 2016, 03:55:38 pm
content: Hello!!I have a home theater SONY DAV-SB100the problem with this is that it plays music like thishttps://clyp.it/mzsdzoelif you cant open it tell me to re-uploadwhat can cause this problem?i have the schematics and if someone know how this can be fixed,pls tell meThx!!

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: October 13, 2016, 04:20:16 pm
content: Tell us more, please. All sources, or just playing DVDs... for example, how does the Radio sound?Maybe by some RTFM it can help???http://pdf.crse.com/manuals/2048709411.pdf

author: christos
author_rank: Regular Contributor
timestamp: October 13, 2016, 04:28:40 pm
content: its the same in every modesame problem

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: October 13, 2016, 04:47:04 pm
content: OK. That helps some. It sounds common to both L, and R ch. audio signal circuits. I'll assume it (distortion) is on Right, as well as Left channels. Sounds like a possible Power Supply issue, or, if it uses a single Stereo Power Output IC, it could be trashed.Look for the schematic. Sony service manuals are typically easy to locate.Happy hunting...

author: christos
author_rank: Regular Contributor
timestamp: October 13, 2016, 04:54:01 pm
content: well thx,,i had some issues with the power supply,,,1 diode was dead and caused no power anywherethx alot!!

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: October 13, 2016, 05:09:04 pm
content: Hi,will be interesting to know what diode that was...http://archivos.diagramas.mx/audio/HCD-SB100%20200.pdf

author: christos
author_rank: Regular Contributor
timestamp: October 13, 2016, 11:06:24 pm
content: Quote from: SoundTech-LG on October 13, 2016, 05:09:04 pmits D901 and a zener at 22v which is not at the schematicshttp://prnt.sc/a8jmx7

author: christos
author_rank: Regular Contributor
timestamp: October 15, 2016, 12:15:48 pm
content: And one more thing,,sometimes(every day) it powers on but no music at all..have to switch it on and off several times until i get that sound plus i have to increase the volume to max until the music is clear.Does this helps anyone to figure out where the problem is coming from ?
Linx10 Broken - Page 1
Forum section: electronics / repair

author: eyesociety
author_rank: Newbie
timestamp: October 11, 2016, 06:51:25 pm
content: Hello.My friend has asked me to have a look and try and repair this Tablet. It has a problem of intermittent power up's.Does any one know were I could get or find a schematic diagram.I have attached a image of the device.Thanks.

author: jkf1000
author_rank: Regular Contributor
timestamp: October 13, 2016, 08:54:17 am
content: In my experience with the windows based tablets the main manufacturer is Viglen which then gets rebadged by the end supplier, I have tried in vain to get any sort of information, especially when it is still in or just out of production. The throwaway society/mentality drives me nuts. I am assuming that you have checked the obvious around the soft start circuits, dry joints, caps etc.. Karl

author: eyesociety
author_rank: Newbie
timestamp: October 15, 2016, 11:49:45 am
content: Thanks for the reply jkf1000I have checked the soft start components seem to be fine.Have brought a board off Ebay to use as a donor board.
Fluke 8060A JFET - Page 1
Forum section: electronics / repair

author: jdownj
author_rank: Newbie
timestamp: October 09, 2016, 10:45:18 pm
content: I am working on a few old Fluke 8060A meters. I have already re-capped a few, and I have a few bad JFETs (Q1). This is used as a series-pass regulator, driven by the MAC chip(U3).The part number from the manual, Fluke 604678, replaced by 721936 only brings up one credible search result(Talon Electronics, 1 in stock but no price). I need at least 2. On the meters I have, the actual parts are marked with a clear Siliconix logo and "J2464" and "J2660." I'm striking out completely to find a source, a datasheet, or a modern replacement. Any help would be appreciated.J

author: dacman
author_rank: Frequent Contributor
timestamp: October 10, 2016, 02:41:55 am
content: I would assume that SEL in the part description means that it is selected. If I had to cross those, I would measure the Vg-cutoff voltage and also the saturated forward Ohms (D to S) with an ohmmeter and convert the value to transconductance. I would then look for an N-channel TO-92 JFET with parameters that are in range (and hopefully get enough to select one that is a close match). A J201 is the same type, but may not be a match.

author: jdownj
author_rank: Newbie
timestamp: October 10, 2016, 02:49:59 am
content: I did see the "Sel" notation with the 721936 part number in the new manual(From the Fluke site). The older manual that matches my serial(I sourced from Artek) calls it 604678 with no mention of selected, even lists it as a manufacturer P/N of "J2464". I think it really is a standard part... but your point is taken, measurement and guesswork may be the only way to obtain enough data to replace.

author: vindoline
author_rank: Unknown
timestamp: October 10, 2016, 11:54:47 am
content: Don't believe that this is a critical part. I've replaced a blown Q1 with a jfet that I had on hand and the power rail came up fine. Sorry, I don't remember the specific jfet I used.

author: retiredcaps
author_rank: Super Contributor
timestamp: October 10, 2016, 03:38:01 pm
content: drtaylor, who was part of the original 8060A team and a member here, but visits infrequently, could probably tell you. Seehttps://www.eevblog.com/forum/testgear/old-fluke-multimeters/

author: retiredcaps
author_rank: Super Contributor
timestamp: October 15, 2016, 04:09:55 am
content: Answered here by Dave Taylor.https://www.eevblog.com/forum/testgear/old-fluke-multimeters/msg1048360/#msg1048360
Repairing a Xerox Alto - Page 1
Forum section: electronics / repair

author: nfmax
author_rank: Super Contributor
timestamp: September 07, 2016, 02:32:11 pm
content: Ken Shirriff is blogging the repair/renovation of a Xerox Alto vintage PC from 1973 (donated by Alan Kay no less) at YCombinator. Episode 5 has just been posted athttp://www.righto.com/2016/09/xerox-alto-restoration-day-5-smoke-and.html, describing a heart-stopping smoke moment while using a vintage (naturally) HP 1670G logic analyser to trace microcode operation.The Alto was the first GUI based personal computer, and introduced Ethernet to the world for the first time (the actual machine beig worked on is a slightly later version).This project would make a great topic for an EEVBlog video interview with Dave, if it could be managed!

author: DaJMasta
author_rank: Super Contributor
timestamp: September 08, 2016, 02:38:07 am
content: I didn't read the full posts, but I got a bit and watched through the videos for each one - very cool stuff! Interesting little tidbits of the very early architecture and already a couple of strange problems you wouldn't see fixing newer gear, and the wire wrap backplane is truly a sight to behold.Having a single main clock for everything.... even the display refresh rate...... wow!

author: nfmax
author_rank: Super Contributor
timestamp: October 13, 2016, 09:42:44 am
content: The saga continues! It now boots, but programs are crashing when they load custom microcode and try to jump to it -. Investigating this sort of issue is what the classic logic state analyser was designed for. All those probes!

author: KK
author_rank: Regular Contributor
timestamp: October 14, 2016, 10:51:45 pm
content: Very cool!
Rohde & Schwarz CMU200 CMU-U99/B99 RF1 level range identical to RF2 option  - Page 1
Forum section: electronics / repair

author: hafrse
author_rank: Regular Contributor
timestamp: October 11, 2016, 07:55:26 pm
content: Hello,I have the"CMU-U99/B99 RF1 level range identical to RF2 option"in my CMU200 but no 2:nd generator (Option CMU-B95/96).Does the CMU-U99 option reduces the RF1 input to 2 Watts ? normally the RF1 accepts up to 50 Watt cont.What I know is that the only Option CMU-B95/96 (2.nd genrator option) reduces the RF1 to 2 Watts which I do not have in my CMU200, could not found anything about that in the spec sheet (attached)Thanks

author: richnormand
author_rank: Unknown
timestamp: October 13, 2016, 01:38:49 am
content: I do have the TxAux on mine and there is an applied sticker with Max 2W on the RF1 connector.I will check again the options when I get access back to my bench (dismantled to make a path to the new furnace before winter).
Anritsu MS2651B SMD component identification - Page 1
Forum section: electronics / repair

author: jkf1000
author_rank: Regular Contributor
timestamp: October 12, 2016, 08:50:44 am
content: I am working through the repairs of my MS2651B spectrum analyzer, I have now got the display working 100% and fitted a new front end mixer which now displays signals on the screen but I am showing several fails during self calibration. In log mode (default) the signal line is sat at just under the top line of the screen which indicates a failed level test. In linear mode (not ideal) the noise floor drops to near the bottom of the screen and signals are displayed correctly and the analyzer is usable.One of the many self cal fails is the 10db IF amp and many of the other fails follow on from the IF stage so my best guess is that the IF amp is affecting the expected levels further down the chain including the LOG detector. My problem is that many of the components seem to be marked with in house codes and many hours of searching have not turned up any usable part numbers. From what I can work out from the component layouts and matching it to the block diagram, the suspect component is marked as RF62, but I just cannot identify what the actual part number is. I have included a few pictures of the board to try and help with the identification.Any help or suggestions greatly appreciated.. Karl

author: BFX
author_rank: Frequent Contributor
timestamp: October 12, 2016, 01:42:48 pm
content: May be 2SC3357 NPN HF transistor.

author: jkf1000
author_rank: Regular Contributor
timestamp: October 12, 2016, 06:44:08 pm
content: Thankyou for your suggestion, I Just looked at the datasheets for the 2sc3357 you suggest and its certainly seem a likely replacement. If anything it appears to be rather over specified having an FT of 6.5Ghz and a dissipation of 1.2watt. The IF stage is only 10.7Mhz but still within the operational range of your suggested device.. Karl
BMM80 MEGGER FAULT - Page 1
Forum section: electronics / repair

author: challie2
author_rank: Contributor
timestamp: October 13, 2016, 11:18:25 am
content: IT WORKS ITS ALIVE!! ITS ALIVE!!!,I had a scan over the entire board which comes in 2 pieces, a control board and a switching and analogue board, turned out to be nothing more than a piece of solder dropping from somewhere, causing a short between 2 pins, i think what it was doing was providing a high signal to that pin which in turn feeds to another pin on another IC that when hi controls another function, so it was switching modes between the 500V &1kV its still a little bit glitched but works without fault so happy. turns out as will that the drawings used by Avo to make the Megger is on the exact same CAD platform and design style as railway signalling drawings which is called BentleyThanks Everyone for your support!
In search of this Sanken STR-F6555. Help - Page 1
Forum section: electronics / repair

author: HunterG
author_rank: Newbie
timestamp: October 08, 2016, 10:13:29 pm
content: Sanken STR-F6555 I can not find any data on this. It's out of a JVC DVHS HM-DH30000U power supply. I think it's bad but with out data sheet I'm kinda lost.I found a 6553 on ebay but again with out data no clue if it's a suitable replacement.Funny part of this, it's been storage for wrapped in cling wrap for a couple of years, I've had people bring me stuff saying it worked when we put it away, or was just setting un-powered. First time for me having something go bad just sitting.

author: amyk
author_rank: Super Contributor
timestamp: October 09, 2016, 12:10:10 am
content: Probably one of this family:http://www.datasheetarchive.jp/STR-F6-datasheet.html
Trying to identify connector pin/crimp type - Page 1
Forum section: electronics / repair

author: tiff_lee
author_rank: Newbie
timestamp: October 08, 2016, 03:09:54 pm
content: Hi all,i'm trying to redo the wiring on a connector from a headunit of mine and was wondering if anyone could identify this pin/crimp type it has a single latching part on the top, all i've found so far online has a latch either side.thanks, Lee

author: Neilm
author_rank: Super Contributor
timestamp: October 08, 2016, 04:41:46 pm
content: Could you post a picture of the housing it came from? It reminds me of a JST or Molex crimp, but it is not quite the one I am thinking.If you are trying to replace it, then you may have a problem as this will require a special crimp tool to crimp correctly. some people claim that pliers can be used but you will never get a good crimp with those. Soldering can be done, but the crimp then has to be cut down so it fits into the housing

author: tiff_lee
author_rank: Newbie
timestamp: October 08, 2016, 05:18:40 pm
content: I figured the housing itself was probably bespoke for the headunit but hoped the connector pins wouldn't be. Soldering would be fine and i'll just trim carefully.
Assistance please: LaCroy Wave Runner 20 xi removing hard drive - Page 1
Forum section: electronics / repair

author: cjobe
author_rank: Newbie
timestamp: October 06, 2016, 06:29:57 pm
content: Hello,Has anyone had experience removing a hard drive from the LaCroy Wave runner 20 xi? Please let me know how you did it and if you hav epictures even better.Thank youCj
Another R&S CMU200 repair thread.  - Page 1
Forum section: electronics / repair

author: CJay
author_rank: Super Contributor
timestamp: October 04, 2016, 10:47:06 am
content: So, my bargain R&S CMU200 is working for the most part but is doing some odd things.On the face of it it seems to work OK, I can see signals where I expect them to be on the spectrum display (power level I'm not sure about yet, I'm still getting used to driving it but see below), the B41 audio analyser would appear to be working as well which is nice.But!The RF signal generator does not work as I expect it to, there is no carrier if I don't turn on modulation, and none in AM, SSB or DSB modes regardless of modulation, even with FM modulation enabled and 1KHz tone/1KHz deviation (or any combination) I get a silent carrier on a separate receiver.Setting FM modulation and coupling the output to any input on the CMU I can measure the carrier generated to within 1.5dB in the power meter mode, I am happy to accept that error is in my cables/adapters so I suspect the Front end and RXTX boards are OK which is quite a relief.Running the self tests gives me numerous failures with the internal RF path and RXTX board, relating to no measured carrier.I have a gut feeling this is due to the no carrier issue in anything other than FM modulation mode as it seems logical to test using an unmodulated carrier.FM modulation test of course also fails.From reading the service manual I think the plug in TXDSP1/AUC1 modules within the Digital board (DIG?) are possibly to blame, does this sound correct?Also, does anyone have a good picture of the RF front end board as seen from the bottom of the instrument? There are four solder pads on the exposed PCB which look to have had a component or connector knocked off of them, next to a small aluminium electrolytic capacitor.

author: CJay
author_rank: Super Contributor
timestamp: October 04, 2016, 06:11:56 pm
content: OK, so, fixed.it now passes FM cal, Internal RF Loop Path 1 and al the other tests I can throw at it without having the calibration fixtures.I've got carrier in all modulation modes now and with modulation off.I had to clean the contacts and reseat the TXDSP and AUC boards in the Dig module, once I'd done that it requested FM calibration and away it went, fully working, I just need to lay my hands on some decent cables to run the remaining self tests as some are falling outside tolerance but count me one happy user.
Repair of a Hypex PSC2.400d plate amp with USB communication issue (solved) - Page 1
Forum section: electronics / repair

author: _Wim_
author_rank: Super Contributor
timestamp: October 24, 2016, 02:21:01 pm
content: Hi, just wanted to post about a simple repair I did last weekend so it might be helpful for others. From a friend I received a Hypex PSC2.400d plate amp, which would not communicate over USB any longer (USB communication is necessary for configuring the DSP). It did power up, but also no sound (probably because no filter was loaded, amp did work correctly when a signal was fed in directly using a siggen)I first started to check the basics (voltages, bad usb connection, visually damaged components) but did not find any problem. The USB communication on this amp was handled by a PIC18LF2455. Next to the pic was a 5-pin header for programming. Tracing out the pins of the header gave the following results:Pin 1(square on solder mask): MCLRPin 2: VddPin 3: VssPin 4: PGDPin 5: PGCThis is the same pin-out of the pickit 3, only missing pin 6 for low voltage programming. The pickit 3 does however not fit directly, because some other components are in the way, so I needed to make an extension cable. On the Hypex website, you can downloaded the software for configuring the dsp (http://www.hypex.nl/downloads/product-downloads.html). As this software also allows you to update the firmware, it contains a folder with the HEX-firmware files. Using MPLab IPE and a pickit 3, I was able to successfully load the latest firmware (remark: amp needs to be powered on to do this, pickit 3 configured not to supply Vdd itself). After loading the firmware, the amp worked perfectly again.
PCB re-plating/ vias repair/ re-routing Companies (services) - Page 1
Forum section: electronics / repair

author: dritech
author_rank: Contributor
timestamp: October 04, 2016, 04:59:54 am
content: Hi all,At my place of work we use PCBs for testing purposes. These are expensive PCBs which tend to get damaged by time and use. Are there any professional PCB repair companies which can offer repair on broken tracks/ damages vias/ damages pads?The requirements are:Ideally have to adhere to IPC standardsThe repaired tracks have to be gold platedAdhesion to PCB has to be goodTolerant to low and high temperaturesAble to repair 0.3mm by 0.76mm padsAny help/suggestions would be greatly appreciated.
Paco S-55 Oscilloscope (Smelly Failure) - Page 1
Forum section: electronics / repair

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 01, 2016, 10:29:28 pm
content: I was tracing down a fault in a stereo when I noticed a funny smell. At first I though the faulty component in the amp was about to blow. Then I noticed the oscilloscope screen was all fogged up. I dismissed it as humidity for a second then I realized...*sniff-sniff*FOG=MAGIC SMOKE!so I unplugged it. But noxious fumes were realesed! (Ewwww!) Capacitor?I'll assess the damage once it airs out a bit. Hopefully it's not to bad like a fire, but there might be a nasty electrolyte spill.

author: oldway
author_rank: Super Contributor
timestamp: October 02, 2016, 06:41:46 am
content: Paco S-55 oscilloscope = tube oscilloscope from....1955Nothing surprising, it may be time to replace some capacitors.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 02, 2016, 12:25:46 pm
content: Someone before me has already replaced some of them, there are orange film caps inside (unless these are original). Not sure about the filters, can't tell if they are restuffed.Oddly enough, couldn't find which one vented if it was. There was no sign of any damage, except the transformer was still warm nearly an hour later. Something must have caused an overload, I'll check the filters for leakage, even though I'd expect them to vent before the transformer overheated.I think the tranny is fine though, it was still working even when smoking.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 03, 2016, 08:07:36 am
content: Some old Oscilloscopes use Selenium rectifiers in the EHT circuit.When those things die,they don't always show any external signs,but they smell bloody awful!!( Like the worst fart you can imagine)

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 03, 2016, 10:50:31 pm
content: Quote from: vk6zgo on October 03, 2016, 08:07:36 amNope, this one uses an HV rectifier tube similar to ones in televisions. Didn't smell like sewer, smelled like a horrible accident in a chemistry lab. Like someone mixed shoe polish with fertilizer and heated it.The HV capacitors are white tubes though, meaning likely paper. Except finding .1uF 1600V capacitors is proving hard, all that comes up are used ones (eeewww). What's the next voltage up? (In modern standards)
LG 32LH20R No sound and screen - Page 1
Forum section: electronics / repair

author: gardenal
author_rank: Newbie
timestamp: October 02, 2016, 05:37:55 pm
content: I am new on fix eleronics. My LG 32LH20R just died after a few second from turn on. It looks like I have replace the mainboard but I just want to be sure. The powersuply board looks ok and the mainboard is receiving the right voltages. The LED and background light works.Any one can help how to confirm if the problem is on mainboard.

author: chavotronic
author_rank: Contributor
timestamp: October 03, 2016, 08:30:16 pm
content: Quote from: gardenal on October 02, 2016, 05:37:55 pmWhat make you think that the supply is ok? What and how did you check it?

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: October 03, 2016, 09:33:17 pm
content: OP I think you will find most LG TVs and monitors suffer from what is known as the"Bad caps plague".. Also looks to have an issue with some zeners on the PSU board.If your search the net you should find diagramshereorhere.SO measure the PSU and post back on the results.Replacement supplies are available just search fleabay or such like.Brendan
Trotec IC060 thermal cam repair - Page 1
Forum section: electronics / repair

author: BFX
author_rank: Frequent Contributor
timestamp: March 30, 2016, 11:17:12 pm
content: Welcome in the hellI bought this camera on ebay because of symptoms (is possible to turn on after enough tries)It's look like power source problem (obviously capacitor).ButIt's no so easy as seems to beThere is no service manual, nothing.I started from beginning .. power supplyEverything is rear-lacquered:( When I can measure something I need to scrape the contactsNext straight forward step check all capacitors ... hmm tantalAll seems to be OK and next step was connect additional boards to check if power consumption will increase.But nothing.When I put together all boards camera looks good started but on display si only one vertical line and after that nothing.Some photos:There is lot of potential problems like RAM, CF card, display, CPU or FPGA.Suggestion's are welcome.To be continue ...

author: BFX
author_rank: Frequent Contributor
timestamp: September 25, 2016, 08:05:02 pm
content: Back to repair and little late update.I did some measurements and testing and finally CF card is broken.I think CF card contains standard FAT partition for pictures, but also some non-standard segment which contain firmware.Question:Know somebody about any tool to repair complete data from CF card? Something like ghost for standard HDD?

author: BFX
author_rank: Frequent Contributor
timestamp: October 02, 2016, 09:56:11 pm
content: Good newsCF card is still bad, but after format on PC camera working fine.Sometimes is problem to bootup sometimes save of image failed but working.Definitely I should buy new CF card.
Portable Dvd Player - Page 1
Forum section: electronics / repair

author: sonicwang
author_rank: Contributor
timestamp: September 26, 2016, 09:00:06 am
content: thanks for taking the time to look at my postso here the problem i am having it was about 6 months ago that i bought a brand new portable dvd player on clearance as i could not pass it up for only $29 as these thing still seem to sell at most places i go to for $70+. i just got around to using it today and having a strange problem when i playback a dvd there is no sound yet if i play a movie from a usb flash drive use the av in the sound works finethis is a strange problem anybody know if there is a fix as the shop i bought it from only lets you return items within 14days

author: sonicwang
author_rank: Contributor
timestamp: October 02, 2016, 11:02:24 am
content: bump

author: Zermalmer
author_rank: Regular Contributor
timestamp: October 02, 2016, 06:49:02 pm
content: Hi,is it possible, that the DVD have Dolby Digital 5.1 and the Player want to 'throw' the sound to a optical/coaxial output?Check handbook and settings on which output the player want to play the sound.Not all players automatically remix the sound for stereo/dolby surround output. sometimes you have to choose the sound in the dvd menu (stereo/dolbysurround 2.1)and sometimes you have to 'motivate' the player to do it.Post model of the device, maybe someone can help with setup.
Tuner repair advice - Page 1
Forum section: electronics / repair

author: Jane
author_rank: Frequent Contributor
timestamp: October 10, 2016, 07:32:54 pm
content: I have a satellite tuner ( made by Eardatek but it seems very similar to ALPS tuner).It does not work.Can anyone suggest a way how to try to repair it?Thanks

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 10, 2016, 07:52:37 pm
content: http://www.dhgate.com/product/alps-rev-m-tuner-bsbe2-801a-with-install/175018391.html
Instek LCR-915 help - Page 1
Forum section: electronics / repair

author: Merlot1970
author_rank: Contributor
timestamp: September 30, 2016, 10:54:55 pm
content: Hello,Does anyone have this meter or the schematic? I need to know the values of 4 resistors on the input.R50, R51, R52 and R53Any help would be appreciated
HP Agilent 54832B Power Supply - Page 1
Forum section: electronics / repair

author: edumopedu
author_rank: Newbie
timestamp: September 29, 2016, 06:47:58 pm
content: First of all I would like to say hi to you all!I am quite a beginner into electronics and that makes my situation even worse. I have purchased a scope from eBay, an HP Agilent 54832B. Unfortunately on its trip the PSU got damaged somehow. To be more precise the +/-5V lines do not output the correct values (instead of 5V I get 05mv). Does any one has any idea if there is a replacement for this PSU (Agilent 0950-4462 Celestica 5100 Series Modular Power Supply,100-240V ,400W)? Or where I could find the schematics of it?

author: edumopedu
author_rank: Newbie
timestamp: September 30, 2016, 06:13:38 am
content: Does any one knows from where I could get a schematic of the PSU? Or if some one could give me a hint about the purpose of the AUX Channel...it would be much appreciated.

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: September 30, 2016, 07:56:17 am
content: There looks to be a service manual at exodus.poly.edu/manuals/HP Agilent. It has some schematics + power supply diagnostics. That might help you.
Heathkit IO-12 - Page 1
Forum section: electronics / repair

author: silverlego3
author_rank: Contributor
timestamp: September 29, 2016, 10:45:14 pm
content: Well, I'm a sucker for old gear, especially when it comes with its own heater. I saw this sad looking box sitting on the side of the road at a yard sale.I couldn't bear to see a piece of equipment with such potential sitting there.So I stopped and picked it up for a few bucks. It has a HUGE bandwidth of 5Mhz.I don't know if it work because the plug is all messed up and it needs new caps, so nothing new for this kind of gear.,But I'll keep you guys updated because I know a few of you have a slightobsessionaffection for things with tubes in them. Once I get pictures of the inside I'll post those too.And for those playing along at home I'll included the schematic.

author: Ian.M
author_rank: Super Contributor
timestamp: September 29, 2016, 11:19:06 pm
content: Sad. That in a yard sale means someone's Grandpa either died or had to go into sheltered housing. If you'd built that would you let it go in your lifetime to anyone except a young enthusiast?

author: tautech
author_rank: Super Contributor
timestamp: October 01, 2016, 09:22:17 pm
content: Is this thread about the same model:https://www.eevblog.com/forum/testgear/heathkit-model-o-12-restoration/IO-12, O-12

author: Len
author_rank: Frequent Contributor
timestamp: October 02, 2016, 01:43:12 am
content: Quote from: tautech on October 01, 2016, 09:22:17 pmNo. But they're similar.http://www.radiomuseum.org/r/heath_laboratory_oscilloscope_o_2.htmlhttp://www.radiomuseum.org/r/heath_laboratory_oscilloscope_i.html
Alinco EDC-144 charger repair - Page 1
Forum section: electronics / repair

author: jpittner
author_rank: Contributor
timestamp: September 26, 2016, 11:28:18 am
content: Hi,does anybody have a schematics / experience with a repair of theAlinco EDC-144 charger? In my one some SMD power transistor labebed "J610" overheats,but I could not find what this SMD code is.Best regards,Jiri
SMPS connundrum - Page 1
Forum section: electronics / repair

author: KSP
author_rank: Regular Contributor
timestamp: September 23, 2016, 09:32:56 am
content: Hi allRecently had a unit go bang without tripping the mains RCD so I decided to investigate. Turns out it wasnt the power supply that actually went bang, but the motherboard. What looks like a decoupling capacitor (SMD ceramic) had for some reason gone short and driven the +24v down to earth. Obviously the capacitor was the failure point, smoke, noise, bad smells etc. etc.I thought I would check the PSU brick to make sure it was still fine. Its a CUI Inc VSBU-120-D524A (5V & 24V OP)http://www.cui.com/product/resource/vsbu-120-dual.pdfUpon plugging it up to the mains and measuring the outputs I was getting my 5V but not my 24V. Checking the unit I removed it from I saw that the input connector to the board had live and neutral switched. I tried connecting it like this and like magic I get my 5V and 24V. Why is this? I can't get my head around this at all.The datasheet states the input connectors pins 1, 2, 3 should be live, neutral, earth respectively. So why does it not work properly unless live and neutral are reversed? And why does only the 24V drop and not the 5V?And finally, could this reversal be the reason that the current surge was not picked up by the RCD?

author: SeanB
author_rank: Super Contributor
timestamp: September 25, 2016, 05:17:07 pm
content: Line and neutral are interchangeable, especially as this could be used in a country where the socket polarity is not guaranteed as to which is live or neutral, so both have to have the same robust insulation with respect to the protective earth.The 24V not showing at all times could be due to a protective device operating, or a cracked solder joint or something like that. You might want to check the secondary side for failure in the 24V side, something there is broken.
HP 4540s 3 blinks - Page 1
Forum section: electronics / repair

author: Kopernik
author_rank: Contributor
timestamp: October 03, 2016, 08:17:50 pm
content: Hi everyone!I have a problem with my HP 4540s.The problem is, that pc blinks 3 times and in a second or two again 3 times than fan spins full speed for a day if I like...I changed memory with the one I know that's works, and it's the same.. I also cleaned memory slot but didn't help..So, what can I try next?

author: CJay
author_rank: Super Contributor
timestamp: October 04, 2016, 01:54:57 pm
content: It's not coming out of reset, the power/thermal management is running the fan full speed and will continue to do so until the main CPU takes over.So, you've tried the memory, does the original memory work in another machine?Have you looked up what three blinks means?Is the LED near the power socket solid or is that blinking?Have you reseated the processor, can you swap it out for a known good one?

author: JFerris321
author_rank: Contributor
timestamp: October 04, 2016, 03:53:36 pm
content: have you tried re-setting the device, this can be done by removing the power from the wall and taking the battery out, then press and hold the power button for 15 seconds or more. after this replace the wall power but not the battery and then turn the device back on.if this does not change the status of the fault i would also try turning it on with no memory in it at all and see if it out puts a different fault code.
TDS3012b   repair tentative. Help needed. - Page 1
Forum section: electronics / repair

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 24, 2016, 09:51:58 am
content: Hi All,I have scored a non functioning TDS3012b for free, and I am trying to bring it back to life.The power supply seems to work, and I have all proper voltages at the BNC connector (+5.1V,+15V, -15V, -5V).The symptom is a blank screen.I have followed the procedure in the service manual I havehttp://exodus.poly.edu/~kurt/manuals/manuals/Tektronix/TEK%20TDS%203000%20series%20Service.pdfbut it does not fit with my device.The J900 connector of the main board ( 26 pins) is different from the one in the manual (12 pins)so I do not know how to proceed.- Does anybody has the proper service manual with the 26 pins J900 connector ?- Does anybody have an idea of what is wrong with this unit ?Thanks

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 24, 2016, 10:51:56 am
content: Now I see that the manual I had was for the TDS3000 and not TDS3000bNow I have found the TDS3000b manualhttp://www.pewa.de/DATENBLATT/DBL_TEK_TDS3000-SERVICE-MANUAL_ENGLISCH.PDFAnd indeed the J900 connector is different.But unfortunately, the troubleshooting procedure is now reduced to the minimal, made for a technician thatknows nothing in electronics.I checked, and have effectively 15V between 1 and 6, which is expected from the previous procedure,but now they do not go further, they just tell to send the device to Tektronix for repair. What a shame !

author: HighVoltage
author_rank: Super Contributor
timestamp: September 24, 2016, 12:44:20 pm
content: I had several TDS3000 scopes fail on me, A,B and C seriesEvery single time it was a power supply issue.Make sure to load the rail with a little current, to see if it stays stable on all voltages.And also look for ripple on the rails.Sorry, I have no more manuals for these scopes since I don't own one anymore.

author: TopLoser
author_rank: Unknown
timestamp: September 24, 2016, 12:56:36 pm
content: I bought and sold 10 or 20 of these, and I always kept a stock of spare power supplies.I think I still have one somewhere, they were only about £30 from Tek.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 24, 2016, 03:17:01 pm
content: Thanks for the feed back.I was hoping it was the PSU, but as far as I can see with my limited knowledge, it seems that the faultis elsewhere.I have measures again the output of the PSU. I have 14.89 V with 100mV ripple with no loadand 20mV ripple with a 100 ohm resistor load.
HP 3478A / Calibration failure - Page 1
Forum section: electronics / repair

author: Eltax1693
author_rank: Contributor
timestamp: September 21, 2016, 08:17:17 am
content: I bought my HP 3478A from Ebay a month ago. It passes the self test, so I sent it to a cal lab. [replaced the battery too]Everything went fine, except the ACV and ACA ranges. "not possible to adjust".What can be wrong?TNX

author: singapol
author_rank: Frequent Contributor
timestamp: September 21, 2016, 10:05:00 am
content: Quote from: Eltax1693 on September 21, 2016, 08:17:17 amThe self test only test display , memory and A/D convertor communication only. Read chapter 3-60 page 3-7of the service manual on self test.. Why Ac volt and current cannot calibrate? Unfortunately I think AC measurement circuit has been damage by previous owner overloading input. Read Service group B - AC volts and Ac current troubleshooting on page 7b-1 of sevice manual. Hope you can find a good technician to repair HP3478A.HP 3478A service manual-http://www.arimi.it/wp-content/Strumenti/HP/Multimetri/hp-3478a-Service.pdf

author: dom0
author_rank: Super Contributor
timestamp: September 21, 2016, 05:58:15 pm
content: iirc the self test does show whether valid calibration data was loaded from the cal SRAM.

author: Eltax1693
author_rank: Contributor
timestamp: September 24, 2016, 11:36:49 am
content: OK, tnx for your help.
electronic circuit /  ultrasonic cleaner - Page 1
Forum section: electronics / repair

author: reneman65
author_rank: Newbie
timestamp: July 06, 2016, 06:36:55 pm
content: hello everyone ,i have a ultrasonic cleaner from the brand EMAG in germany , the type of unit is the EMMI 40 HCnow the problem is that the electronic circuit is deffect ,,,,the are two FET'S IRFP 460 L on the board that where blown .i replace those FET'S and the unit stil don't work ?so i concentrate on the one 16 DIP IC that i think is also deffect ,,but the identification number is scratched of by the manufactorcan someone help me with this to figure out what kind of IC is needed for this 38 khz cleaner ...i found some number stil readable and looks like 44 number ..it has to be a oscilator IC in the 38khz rangethe output of the ic i found that it drives two transistors one pnp and one npn .i know that the ic has a vcc + on top (next to notch) and ground at other side over length of icalso the output pins are on the oposite site of vcccan anyone help ?thanks rene van steenis

author: seeigecannon
author_rank: Newbie
timestamp: July 06, 2016, 09:10:38 pm
content: You have a couple options for a bodge circuit here:1: Use a 555 timer to replicate that 38kHz waveform. If the unknown chip is a micro-controller of some kind then you will loose the timer feature (if it has one).2: Use a micro-controller of some kind to create the 38kHz. This will allow you to maintain the timer, but this will also allow you to sweep between 37 and 39kHz. This will give you a better cleaning cycle as you will eliminate standing waves.If either of these sound like something you would be willing to try then let me know and I will go into more detail on how to implement the fix.

author: Seekonk
author_rank: Super Contributor
timestamp: July 06, 2016, 09:36:42 pm
content: I haven't looked it up at all, but those two pins tied together makes me think it is a TL494.

author: 1001
author_rank: Contributor
timestamp: September 24, 2016, 08:33:33 am
content: it should be a CD4046B, phase-locked loop device, can you post a pic of whole pcb?
Iso-Tech IPS2302A PSU schematic?  (2x 30v 2A + 5v 3A) - Page 1
Forum section: electronics / repair

author: m100
author_rank: Regular Contributor
timestamp: September 21, 2016, 06:58:55 pm
content: Does anyone have a schematic for an Iso-Tech IPS2302A power supply? Externally similar to quite a few other far east designs the main pcb does not seem to match any I've found on here or elsewhere.Front Panel view & Main PCB (bad light and ancient phone so pretty low res)

author: macboy
author_rank: Super Contributor
timestamp: September 24, 2016, 12:26:49 pm
content: Try this onehttp://www.ko4bb.com/manuals/download.php?file=Tektronix/Tektronix_-_PS280_Power_Supply/Tek_PS280-283_Service_Manual_Schematics.pdfIt is for the Tektronix PS280/PS283. I have a few different manuals for this type of widely cloned/rebadged supply, and the Tek manual is in a different league from the others for obvious reasons. It seemed a pretty good match to my IPS2303D (digital display). It doesn't have the analog display part, but the power section is all there including master and slave sides as well as the 5 V section.Note that the 5 V section has fold-back current limiting. So it will deliver its rated 3 A into a 1.66 Ohm load, but if you connect a 1 Ohm load, it will deliver less than 3 A, and even less still with a short circuit. Initially I thought my supply had a fault since it wasn't cranking 3 A into a short, but this is by design.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 25, 2016, 09:54:58 am
content: THis schematics is from SL-1731SB or PS23023, a 2x 30V 3A PSU,Which has larger transformers, and two separate boards, but it is the same level of construction, and there is good chancethat the schematics are very close.
My HP3456A display failed this morning... [FIXED] - Page 1
Forum section: electronics / repair

author: enut11
author_rank: Super Contributor
timestamp: September 23, 2016, 05:27:29 am
content: I could not find a reference to this problem on the Forum. After weeks of faithful service, my HP3456A display failed this morning. It only shows first and last digit, nothing in between, even when I run the self test. Obviously, it does not respond to any input. I have yet to pull it apart. Any ideas on what it may be or where to look?enut11

author: singapol
author_rank: Frequent Contributor
timestamp: September 23, 2016, 07:05:09 am
content: Read the service manual but open up first to have a look. Could be as simple as cracked solder joints in the display section or something else. Experts will join in shortly. calling Mr. Tin?http://elektrotanya.com/hp_3456a-mil_calibration_manual.pdf/download.htmlMr.Tin-https://xdevs.com/fix/hp3456a/Operation and service manual(not the actual service one, see xdevs site above)HP 3456A Digital Voltmeterhttps://www.sonoma.edu/esee/manuals/03456-90006.pdfHigh res manual here: 42Mbhttp://bama.edebris.com/manuals/hp/3456a/

author: enut11
author_rank: Super Contributor
timestamp: September 24, 2016, 02:49:50 am
content: Yippee. Thankfully some jobs are easy and this was one. Re-seating the blue connector behind the display brought all the missing digits back.
bush DLED32165HDDVD with vestel 17IPS71 PSU - Page 1
Forum section: electronics / repair

author: john72
author_rank: Newbie
timestamp: September 21, 2016, 01:58:32 pm
content: Hi all, just got this TV on the table for repair thought it would be an easy one tho it might still turn out to be.Complaint is no picture / Back light.When you switch it on standby light flashes when you press power to bring it out of standby accompanied by a brief flash of the back lights then nothing.I've checked diodes because the other tvs have usually proven to be either shorted diodes or bad caps.All caps test bad on this board with my peak atlas ESR meter. They are either high ESR or gone high / low capacitance.I'm fairly confident that they need changing and may well fix my issue.However I've been checking some voltages at the LED connector and I see it starts high when the back light flashes on briefly then slowly ramps down. Then if I check the voltage on the negative side of the back light, it ramps down slowly.I'm unsure if at this point I have a shorted LED or the PSU cannot supply the voltage and is shutting down to protect itself.Only equipment I have at my disposal right now is the Eevblog BM235 and my peak ESR70 meter.Any pointers as to what to check next would be greatly appreciated.Thanks John.Edit: Just to add that when checking voltages of the LED connector (CN6) red positive immediately jumps to around 45v when the back lights flash on and then slowly decrease. Black negative goes to about 80v and slowly decrease.
Ghost in the Machine??  Item turns back on after being turned off.  Panasonic  - Page 1
Forum section: electronics / repair

author: gooseEL34
author_rank: Regular Contributor
timestamp: September 20, 2016, 04:11:09 pm
content: Hey guysI am handy with a VOM, oscilloscope and soldering iron but I mainly work on non-micro-component devices (guitar amps and pedals).I have a favorite CD/Tape/Tuner unit in my shop. It is a Panasonic SA-PM39D and here is the symptom:A few seconds (10-15) after I turn it off (hit the soft push button), it will restart in demo mode.I hear a relay click when I turn it off and again when it turns back on spontaneously.I really do not know how these type of units do their switching on and off. I am assuming that I might have some issue in the circuit whereby a relay is not holding open or closed based on a voltage dropping or being applied due to a bad cap.Might I be in the ballpark? Also, with no online schematic, I am just guessing at this point.Any help would be appreciated. You can talk in EE terms as I am aware of the basics (I understand resistor, capacitor, electrolytic cap, relay, short to ground, etc...). Digital logic and solid state design is my weakness as my stuff is generally basic (take 120v wall voltage, step it up to 390v and then filter it and supply it to the various tube stages).ThanksTim

author: singapol
author_rank: Frequent Contributor
timestamp: September 20, 2016, 04:35:22 pm
content: From pg.9... Look at the pg.9 link. Picture is worth 1K words.When the unit is first plugged in,a demonstration of itsfunctions may be shown on the display.If the demo setting is off, you can show a demonstrationby turning on the demo.The display changes each time the button is held down.Demonstration(demo on)@ANO DEMO(off)You can reduce the power consumed in standby modeby turning the demonstration off.NoteYou cannot turn the demo function on and off whenthe unit is onPage 9:http://www.datasheetspdf.com/PDF/SA-PM39D/635951/9User manual-https://support.panasonic.co.nz/docstore/SC-PM39%20Operating%20Instructions.pdf

author: Len
author_rank: Frequent Contributor
timestamp: September 21, 2016, 02:50:18 am
content: It's not the only haunted radio to turn up recently:https://www.eevblog.com/forum/blog/eevblog-922-mailbag/