hybridfree/eevblog-posts huggingface dataset:
Thurlby Thandar TGA1230 arbitrary waveform generator, display fault - Page 1
Forum section: electronics / repair

author: CambridgeMart
author_rank: Regular Contributor
timestamp: August 05, 2018, 09:32:42 pm
content: I've just bought a TTi TGA1230 in lovely condition; it appears to function correctly except that the LCD is very smeary, I've tried adjusting the contrast via the adjustment hidden behind the hole in the panel and it's made a marginal improvemnt, but it's still next to useless. Before I dive in, I was wondering if anyone has a service manual for this or the closely related TGA1240?Cheers, Martin

author: bd139
author_rank: Super Contributor
timestamp: August 05, 2018, 09:37:36 pm
content: Looks like a standard 20x4 LCD module. TTi used off the shelf parts where possible. I’d whip it out and stick a new one in.Unfortunately no service manual I can see. Drop TTi an email - they are usually very helpful in this respect.

author: Specmaster
author_rank: Super Contributor
timestamp: August 05, 2018, 09:49:54 pm
content: Quote from: CambridgeMart on August 05, 2018, 09:32:42 pmI think I almost got that as well, was it the one on Ebay where seller mentioned the screen was sometimes smeary?

author: bd139
author_rank: Super Contributor
timestamp: August 05, 2018, 10:28:10 pm
content: Damn didn't see that on eBay. Good priceLooking at the picture on ebay sold items if it is that one, it's a duff module. About £10-15 on RS so no biggy.Edit: to note, I saw a device with one of those modules in that looked like that after it had air con blown across it for a long time.

author: CambridgeMart
author_rank: Regular Contributor
timestamp: August 06, 2018, 06:56:38 pm
content: Yes, the one in St Neots and he did mention the display was unclear.Located a 4x20 display that matches the size and, hopefully, pinout for £6.00, should be here in a day or 2.Having opened it up I've found it's circa 1996, would never have believed it from it's external condition, this clearly never lived in one of my industrial labs!

author: Specmaster
author_rank: Super Contributor
timestamp: August 06, 2018, 08:03:55 pm
content: Yes thats the same one that I was looking at but discounted it because it didn't go high enough, although the screen did actually reasonably clear in the photos.
Anritsu MG3681A RPP(Reverse Power Protection) fault - Page 1
Forum section: electronics / repair

author: pa1u
author_rank: Newbie
timestamp: July 10, 2018, 10:41:13 am
content: Hello to you all.I am maarten pa1u. I got a mg3681a defect from a other HAM.First i repaired the power input terminal. The nulterminalwas intermittand.The mg3681 is powering up but hangs on the RPP.(Reverse Power Protection).I tried to reset but the fault comes back.I read in the manual it is a mechanicly switch for protection.Anyone knows this problem and the way to solve it.Greetz maarten pa1u

author: stevesousa
author_rank: Newbie
timestamp: August 05, 2018, 11:04:20 pm
content: Hello,Try disconnecting the flat cable that controls the attenuator, inside is the rpp detector. Do this with the power off or you may increment your rpp counter.disconnect the rf input of the attenuator and see if you have a signal there.Good luck
Need info about 35V 1000MFD cap in MC8000 Vertical Turntable. - Page 1
Forum section: electronics / repair

author: Aim eYacht
author_rank: Newbie
timestamp: August 09, 2018, 10:48:06 pm
content: Hi there,I'm trying to restore this wonderful piece and I've run into a rather odd situation. The cap I need to replace is a Unicon 35V 1000MFD or 1,000,000uF. Is this right or some kind of joke which I don't understand the context of?Thanks in advance.

author: tautech
author_rank: Super Contributor
timestamp: August 09, 2018, 10:59:24 pm
content: Haha, yeah old stuff was listed in MFD, shorthand for micro farad or as we all know and accept now as uF.1000uF 35V is a common value but if in an SMPS application a low ESR cap should be used.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 09, 2018, 11:28:41 pm
content: i dont know where you took this value there is no 1000 MFD it this turntablemfd stand for micro farad in the time it was produced, you must mean EX: c115 is a 1000ufd 35v capacitorDo you know the size for an 0.1 farad or 1000 mili farad capacitor at 35v?? it would be around 5 inches diam by 11 inches long canister lolllservice manual :http://s.siteapi.org/500b43cd79ebb4d.ru/docs/253a5d122b576606a1db3b43fa6ad83481427657.pdfor you have some small capacitor with the number 103 or 103m, they would be 0.01 ufd, an number 104 would be an 0.1 ufd, an 105 would be an 1 ufd, they are exponent numberingsome surface mount resistors have this coding too, 102 would be an 1k resistor, 101 would be 100 ohms, 103 would be 10k ohmsWhere i work, we have 470 for an 47 ohm and or the same part is written 47 with an other distributorand now we have other numbers for the same part

author: oventech
author_rank: Contributor
timestamp: August 10, 2018, 01:03:00 am
content: Found the Service Manual on Vinyl Engine.com. Just register and download for free if you haven't been there before.https://www.vinylengine.com/library/mitsubishi-diatone/mc-8000.shtmlAlso check out audiokarma.org. Plenty of good people who will help there.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 10, 2018, 03:58:03 am
content: i would change all the supply capacitors as a start, it would cover all the main dc linesc114c115c116c905c906c907c910c912c913c914c918c953 up to c963After that you may have to change all the other chemicals around the ic's, the power amplifier, if you have too much noise or hisss etc...

author: Aim eYacht
author_rank: Newbie
timestamp: August 11, 2018, 12:25:04 pm
content: As usual, you guys are so very helpful.Thank you for all your replies. Here's a picture of the cap.

author: Chris56000
author_rank: Frequent Contributor
timestamp: August 13, 2018, 04:51:24 am
content: Hi!A nice Service Manual that's been decently scanned from a proper Factory Original for a change!Old Japanese & American practice was to use 'M' for "microfarad" & "P" for picofarad (nanofarads were usually written as thousands of PF) - with this style and age of manual, C & R values over 1 are shown in "picofarads" and "ohms" if the unit is not specifically mentioned!Chris Williams
I need help troubleshooting Dave's soft latching power switch design - Page 1
Forum section: electronics / repair

author: itsemre
author_rank: Newbie
timestamp: August 05, 2018, 12:12:49 pm
content: I designed and built a circuit that turns on and off using Dave's soft latching power switch circuit but it has some weird problems. When I give the circuit power it doesn't turn on and when I push the button it turns on, like it should. However, when I push the button again it doesn't turn off, no matter what I do I can't get it to turn off. Another interesting thing is that I can turn it on by just touching the switch's leads. Please help, I need to get this project finished as soon as possible.You can find a picture of the pcb and schematic here:https://drive.google.com/open?id=1EUNygCo53HiGjN6LQdfGfHrjWLBEhBag
sony tcm 450dv - Page 1
Forum section: electronics / repair

author: sonicpainter
author_rank: Newbie
timestamp: August 05, 2018, 09:04:23 am
content: hi got a sony tcm 450dv off ebay i powered it up one of the reels is spinning on the right without pressing any buttons ,took it apart starting to think it could be one of the switches power,rec/play any help on this matter would be appreciated.

author: cheeseit
author_rank: Regular Contributor
timestamp: August 05, 2018, 11:32:44 am
content: SM herehttps://elektrotanya.com/sony_tcm-450dv.pdf/download.htmlWait for the ...processing... below the preview to change to a download link
Component Identification - Page 1
Forum section: electronics / repair

author: mechanicmav
author_rank: Newbie
timestamp: August 03, 2018, 07:06:37 pm
content: First post ever on the EEVBlog so I'm not certain which category this question falls under. I have an Automotive Meter that was experienced an overvoltage event and it let the smoke out. From what I can tell the only component that was affected was what looks like a diode however I am unable to identify the markings. If someone from this forum could be so kind as to help me I would sure appreciate it. I included an image of a good component with the same markings to make it easier to identify. The identifiers on the part are what look like DH948 and U V. Usually Google can turn up something but it was not helpful in this case so I am turning this over to the experts. Please see attachment.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 03, 2018, 08:30:22 pm
content: could be an protector device tvs ... tds ... or simply an diode as you say, can you give us the model, a brand ... we see only the pcbIf this part is shorted out, if so you could remove it and see if there any voltages on the pads ac or dcmaybe the meter will start ??

author: mechanicmav
author_rank: Newbie
timestamp: August 03, 2018, 09:05:43 pm
content: Thanks for the reply, The device is a AutoMeter Air Fuel Ratio Gauge Model 4378.

author: mechanicmav
author_rank: Newbie
timestamp: August 03, 2018, 09:24:29 pm
content: Here are a few more photos if it helps.I didn't have access to my soldering iron in the office. I plan on removing it when I get home to the man cave and then measure the continuity from B+ to B-. Currently Its shorted so once its removed I hope it will function.

author: amyk
author_rank: Super Contributor
timestamp: August 04, 2018, 12:31:32 am
content: SMAJ20CA.
Omega RD-2010 - Page 1
Forum section: electronics / repair

author: Floopy
author_rank: Regular Contributor
timestamp: June 12, 2018, 04:13:52 pm
content: Hello,Yet another repair on top of all the others I have to finish.Here's my problem. I got this nice chart recorder the other day. Unfortunately it didn't come with the power supply or anything else. The first thing I did was oil the rails and take it apart. I traced the power supply input jack all tha way back to a diode package. I assumed that the power input must be AC at around 10-20RMS. I couldn't find any schematics of the unit online so I had to assume. To make a long story short I left it on for about 30 seconds without a problem, when I reached over to turn on the function generator it went pop, flash of light and the magic smoke came out.What could have caused this? Bad capacitors? The other capacitors look sketchy. Also what is the name of the blown semiconductor.Thanks!

author: Floopy
author_rank: Regular Contributor
timestamp: June 12, 2018, 04:54:56 pm
content: Okay I found the manual with schematic. The input requirement is 12VAC, I was putting 13VAC. I don't think it was my fault.Manual below.https://www.omega.com/manuals/manualpdf/M0455.pdf

author: Floopy
author_rank: Regular Contributor
timestamp: June 12, 2018, 06:31:25 pm
content: Is that a L272M ?That fried IC is what I'm stumped on.Someone else posted about it, but they removed it.

author: Floopy
author_rank: Regular Contributor
timestamp: June 13, 2018, 02:21:23 am
content: I cleaned the op amp and it says L272M, at least the visible portion. The pins that melted are all connected to each other. The fried pins of the 272 are connected to one of the input pins of the 324 which is fried also. The rest of the caps are bulging. Could this have been caused by the cap blowing? I can't remember which came first the burst of light or the pop. I think it was the pop, but I can't confirm. If so, can I just replace the fried parts and that would work fine afterwards?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 03, 2018, 07:58:10 pm
content: That damage looks really bad. It usually take more than just a bad cap - more like mains current flowing through the circuit or operating a 110 V instrument at some 400 - 600 V or maybe lightning strike (a milder case), maybe a rectifier giving full AC through (which is very rare). With those blown parts chances are other parts are bad too. It usually takes several (maybe 10s) l amps to blow the pins of a DIP chip.
HP8590L A4 mixer module insides - Page 1
Forum section: electronics / repair

author: Bjoern
author_rank: Contributor
timestamp: July 28, 2018, 11:10:03 am
content: Does anybody know what these C2 components are ?I expected to find two diodes inside the mixer but only found capacitors and resistors ?!There are no components under the soft grey pads.

author: RFMWdude
author_rank: Contributor
timestamp: July 28, 2018, 11:44:21 am
content: They are just what you would expect here: Mixer diodes. To be precise: Avago (now Broadcom) HSMS‑2822.Datasheet:https://docs.broadcom.com/docs/AV02-1320EN

author: Bjoern
author_rank: Contributor
timestamp: July 28, 2018, 03:20:05 pm
content: Thanks for the TIP !!I measured them and they actually workBack to the drawing board.Would you have an idea why my SPAN below 100khz might not work but above its ok ??

author: Bjoern
author_rank: Contributor
timestamp: July 28, 2018, 03:41:16 pm
content: Can I ask you:i see some spikes of my calibration signal on the screen.When I disconnect the YIG from the A4 mixer the spikes on the screen disappear.Can I conclude from that, that the YIG is working or can there still be issues with the YIG causing amplitude issues ?

author: Bjoern
author_rank: Contributor
timestamp: August 03, 2018, 05:59:18 am
content: Today I did some more measurements on the YIG supply buy adding resistors in series of the main coil and the FM coil to measure the current (by measuring the voltage over the resistors).I believe the signals for both coils are OK which rules out errors on the analogue board.Since I am unable (due to my instruments) to measure the output of the YIG or any mixer in the gigaherz range I am still not sure if the output of the YIG is too low, causing low signals further down the signal path.I connected a 10Mhz sine wave signal with 1.2 RMS volt to the SA but the SA shows only several millivolt on the screen. Somewhere the signal gets depreciated.How canI find where the signal decreases without being able to measure the 2.12 Ghz ??
Smartphone Touch Screen Replacement - Page 1
Forum section: electronics / repair

author: orbanp
author_rank: Regular Contributor
timestamp: August 02, 2018, 03:32:26 pm
content: Hello Everyone,My son dropped its phone, the glass on the screen cracked.It is a Xiaomi Mi Max I phone.The phone works just fine, and we put transparent packing tape on the screen as a temporary fix.(The touch function still works!)We got a replacement digitizer, the glass part of the screen.However, the the glass and the LCD screen seems to be fused together, there does not seem to be an easy way to remove the cracked glass.I heard some people using a heat gun...Any advise on how to remove the glass without damaging/destroying the LCD part of the screen?Thanks, Peter

author: Doug Brewster
author_rank: Contributor
timestamp: August 02, 2018, 03:54:18 pm
content: Looks like this guy doesn't use heat...

author: orbanp
author_rank: Regular Contributor
timestamp: August 02, 2018, 04:29:50 pm
content: Hi Doug,Thanks for the link!Looks like this guy replaced both the LCD and the glass, he used some adhesive tape in an "X" pattern.That would not work for just the glass!I did fond another video where they show the heat gun approach:So it is doable.Just curious what kind of industrial glue did they use to secure the top and bottom edges?Thanks again, Peter

author: Rasz
author_rank: Super Contributor
timestamp: August 02, 2018, 09:23:28 pm
content: UV curing glue, but why bother? whole screen assembly is $22-39
OS-8G/U oscilloscope display problems - Page 1
Forum section: electronics / repair

author: knoble
author_rank: Newbie
timestamp: August 02, 2018, 02:39:14 pm
content: Hi all, just bought this oscilloscope, works pretty great so far except for this one problem with the display. I’m very new to oscilloscopes / electronics repair in general so pardon me if I can’t explain this correctly (the video should hopefully give you a better idea of the problem), but it seems as if the aperture or whatever mechanism the focus uses is partially stuck? The other guess I had was that there is something wrong with the deflection plates inside the CRT, but again, a complete guess. As you can see, the signal gets split into two regions, and the focus knob moves them apart. I’ve trawled through this forum and others trying to find a comparable issue, but there were none that I could find, so I figured I’d post this and hopefully somebody with the same problem might one day come across it. I appreciate any and all advice I can get, thanks!Video demonstrating the issuehttps://youtu.be/yTDS3X7IJzs

author: ArthurDent
author_rank: Super Contributor
timestamp: August 02, 2018, 03:39:27 pm
content: The first thing to keep in mind is this is a tube type scope and with voltages up to the 500V range inside the case so if you aren't used to working with equipment like this it would be best to forget it. Having said that, the OS-8 wasn't a bad general purpose scope when it was made. Because of the age the first thing to check are the two electrolytic capacitors that are probably bad. The cover on the back will allow you to put the jumpers in the external position (with POWER OFF!) and bypass the deflection amps. If you get a dot in the EXT position that you can focus, etc., then it is possibly just the caps I mentioned (C134 & C135). It could also be a tube problem so if you have access to a tube tester that might help as well but just because a tube shows it's weak doesn't mean it should be replaced.Here is a link to the service manual.http://www.mcmlv.org/Archive/Military/TM11-1214A%20OS-8C%20Oscilloscope.pdf

author: knoble
author_rank: Newbie
timestamp: August 02, 2018, 04:30:05 pm
content: Thanks for the reply! I definitely appreciate the dangers of poking around the internals without having much experience working with high voltages. I did open it up last night just to take a look for any glaring problems and I actually believe you might be right about C134-135 if they are the ones on a board mounted to the base of the unit, pretty centrally located under the tube. I could spot some leaking coming from some larger capacitors in that area. Seems like a pretty quick fix for someone who knows what they’re doing, I might just hand it off to a local electronics repairman and ask them to replace those capacitors. Would that be reasonable?
ODIN OEC12C887 replacement - Page 1
Forum section: electronics / repair

author: Claudiu
author_rank: Newbie
timestamp: August 01, 2018, 11:15:41 am
content: Hi, everyone! I need to know for shure the replacement part for Odin OEC12C887 made by Maxim-Dallas, since TME is the only trustable store in the nearby.I know only that can be one of this: DS12887, DS12887A, DS12C887. Prehaps anyone have some info on this Odin chip?

author: coromonadalix
author_rank: Super Contributor
timestamp: August 01, 2018, 08:36:29 pm
content: If i recall the Dallas DS12887 is a direct match for it, Dallas and Odin where pin compatibles
LM13080 replacement - Page 1
Forum section: electronics / repair

author: Floopy
author_rank: Regular Contributor
timestamp: August 03, 2018, 05:18:32 am
content: I don't know if this is considered "Repair", but if anyone wants to move it feel free.I'm currently repairing a device that has two of these LM13080N programmable operational amplifier. One is dead and I can only find two supply sources that are somewhat not trust-able. I'm wondering if anyone knows of a modern replacement?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 03, 2018, 06:45:28 am
content: Finding a modern replacement would be difficult, as the chip has a rather odd pin-out - compared to the more normal OPs and the high output current could be a problem.There might be chance to use a more normal OP, depending on the way the chip is used. Especially if used with fixed setting for the bias currents, so that a more normal OP could be used that comes close to the properties at the chosen bias. It would still need an adapter for the pinout.

author: Floopy
author_rank: Regular Contributor
timestamp: August 03, 2018, 03:50:53 pm
content: https://www.ebay.com/itm/Vintage-National-Semi-LM13080N-Programmable-Power-Operational-Amplifier-DIP-8/323329622759?epid=15015800664&hash=item4b47f282e7%3Ag%3AgqMAAOSwSRVamDOI&_sacat=0&_nkw=LM13080N&_from=R40&rt=nc&_trksid=m570.l1313\There is some here, I might just go with that.It's used in controlling a motor. In a pen plotter. I made a post about it earlier a while back and I got around to putting it on the bench.https://www.eevblog.com/forum/repair/omega-rd-2010/msg1603882/#msg1603882

author: David Hess
author_rank: Super Contributor
timestamp: August 06, 2018, 01:30:51 am
content: The LM13080 is an unusual part with a single supply input, a high current output, programmable operation, and shutdown. I do not think it was even second sourced so there is not going to be any modern direct replacement. Something like an LA6500 would probably work assuming that the design does not require the programmable features.
Samson XP360B - Speaker replacement - Page 1
Forum section: electronics / repair

author: lean032
author_rank: Newbie
timestamp: July 24, 2018, 08:06:27 pm
content: Hi everyone!!!I own a Samson Expedition Express XP360Bhttp://www.samsontech.com/samson/products/portable-pa/expedition-rechargable/expeditionexpress/I would like to replace the tweeter but I can´t figure out how to remove the front panel to access to the speakers.Can anybody help me with this???Thanks a lot!!!LF

author: envisionelec
author_rank: Frequent Contributor
timestamp: July 31, 2018, 07:44:38 pm
content: The metal grille will be held in with hot melt glue or other sticky substance. Warm the entire speaker in direct sunlight then unfold 3 or 4 paperclips into a shape that can be looped through the grill in each corner. You can also use a pick-type tool. If the glue is soft, it won't take much pulling, but be persistent. The grill will come out eventually.
Looking for documents: Hitec AC1 Arrange Composer (built in Widdern, Germany) - Page 1
Forum section: electronics / repair

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: July 31, 2018, 05:48:46 pm
content: Dear all,this is more of a long shot, but maybe someone of you can help me out.I am looking for documentation on a late 80s Midi arranger/sequencer 19'' rack module. The German company "Hitec Musikelektronik GmbH Widdern" seems to have gone out of business in 1991."Hardware and Software by Ralf Bauer" is what the device states on boot.I would be very grateful for any information regarding this thing.Thank you and kind regards,Frederik
TDK-Lambda SMPS fail-repaired - Page 1
Forum section: electronics / repair

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: July 31, 2018, 03:24:38 pm
content: This TDK-Lambda LS100-12 ($32 at Digikey) failed, no power LED. It seemed a very intermittent rare fail for a few months. This may/may not be a common failure mode for these. After spending some time checking caps, resistors, resoldering the primary side, I went to test the power Mosfet P11NM60N and desoldered the outer 2 leads, the part fell off the board. You could not see this broken drain lead, there is a full rubber insulator around the device. Obviously a mechanical failure that started on installation of the part during assembly. No stock at digikey/Mouser for P11NM60N. Will have to sub it with something close. Hope this helps someone.
Phasing dots on Minicircuits ADTL1-4-75 RF transformer - Page 1
Forum section: electronics / repair

author: rfengg
author_rank: Regular Contributor
timestamp: July 31, 2018, 07:20:11 am
content: The phasing dots on the Minicircuits ADTL1-4-75 RF transformer is driving me bonkersAs per their data sheet athttps://www.minicircuits.com/pdfs/ADTL1-4-75.pdf, the phasing dots on this transformer have both dots shown on the same winding.........what exactly does this mean?Usually the phasing dots on a transformer give information on the winding direction of the coils , but what do two dots on the same winding mean?

author: ArthurDent
author_rank: Super Contributor
timestamp: July 31, 2018, 10:54:20 am
content: It all depends on the design and what the transformer is used for. Here are some examples.

author: Bud
author_rank: Super Contributor
timestamp: July 31, 2018, 11:19:30 am
content: This is a transmission line transformer and the dots mark primary and secondary terminals which are in-phase. If you swap the secondary terminals your output voltage will be 180 degree out of phase vs input voltage. Note that there is no galvanic isolation in TL transformers between input and output. You should know where and how to use them.

author: ArthurDent
author_rank: Super Contributor
timestamp: July 31, 2018, 11:38:13 am
content: Here's another picture with the phasing dots on the same winding. Google 'balun' and 'unbalanced to balanced'.
Help identifying fried components - Page 1
Forum section: electronics / repair

author: Spray110
author_rank: Newbie
timestamp: July 26, 2018, 04:19:34 pm
content: Hi there!I have a pcb for an HP 2311xx series monitor with fried components, do any of you electricians know what I could use to replace these with?The pcb model is 492A00191200H, and unfortunately I cannot find a clear enough picture to identify them.Thanks!

author: Nusa
author_rank: Super Contributor
timestamp: July 26, 2018, 04:47:07 pm
content: Here's some better pictures. Zoom in and you can make out the chip labeling.

author: Spray110
author_rank: Newbie
timestamp: July 26, 2018, 05:05:06 pm
content: Thanks! The smaller one is still quite hard to make out, but I'll try! Also, any idea of how to search for these? I don't know how to type the information in. The bigger one seems to be AX5630-33 1021A but nothing really shows up when I search for it.*edit*Rather, is there a way to see what values they have?

author: amyk
author_rank: Super Contributor
timestamp: July 27, 2018, 02:29:00 am
content: Quote from: Spray110 on July 26, 2018, 05:05:06 pmThat's because it's anAX6630, 3.3V LDO.The other one appears to beRT8253AH.

author: Spray110
author_rank: Newbie
timestamp: July 30, 2018, 11:43:59 pm
content: Quote from: amyk on July 27, 2018, 02:29:00 amThank you so much for the help!One more question, is the model name important, or is it about the values? so as long as the values are correct, the replacement doesn't have to have the same exact writing on it?*edit*Also, I just noticed I need to replace yet another fried component. It's got the exact shape and size as the AX6630 one, the writing says NIKOS P8008BD QNC6N0203 and I can only seem to find replacements from sites like aliexpress. Is there a way to read the values of it based on the writing? I cannot seem to find some information about this particular model.

author: amyk
author_rank: Super Contributor
timestamp: July 31, 2018, 12:28:01 am
content: QuoteWhat do you mean exactly? The replacement is pretty much guaranteed tonothave "the same exact writing on it", because part of the marking is the datecode. However the part number should be the same otherwise, although for more "generic" components you can substitute one with equivalent specifications. I'll let others here elaborate on the finer points of that.

author: Spray110
author_rank: Newbie
timestamp: July 31, 2018, 01:00:46 am
content: Quote from: amyk on July 31, 2018, 12:28:01 amThanks! I guess I'm just kind of lost searching for replacements. I've been searching for parts with the same values over at Mouser, but I cannot seem to find fitting replacements, the values just doesn't match up. Is it normal, having to search far and wide before finding such simple parts or am I just an obvious newbie?
vintage AWA-F240 awa240  distortion and noise meter repair  - Page 1
Forum section: electronics / repair

author: ErwinsCat
author_rank: Regular Contributor
timestamp: August 04, 2018, 09:25:24 am
content: I recently posted a question in the forum (unfortunately nobody answered yet!)https://www.eevblog.com/forum/beginners/measuring-thd-with-vintage-awa-f240-distortionnoise-meter/anyways later when I looked at the photos, I realized the meter red texts and lines, faded off, probably because of the age of unit and UV. I decided to restore the meter face and I thought just post the images and results maybe someone interested to see inside this old unit.interestingly they used a piece of un-etched fiberglass PCB for the meter face!
Repairing Car AMP MOSFET compatibility question - Page 1
Forum section: electronics / repair

author: denimdragon
author_rank: Regular Contributor
timestamp: July 27, 2018, 10:30:03 pm
content: I'm repairing a Memphis Audio 16-PRX1000.1 and there are 4 blown N-Channel Mosfets but they seem to be odd-balls and I can't find them except on eBay. What I need to know is what datasheet specifications do I need to look at in order to use something comparable or better. I don't really want to get these from eBay as this is for a client and I can't risk it.RU61150 Datasheet :https://cdn.datasheetspdf.com/pdf-down/R/U/6/RU65110R-Ruichips.pdfI know the BVdss, Rds(on), are important, but what else should I look at when replacing a mosfet with another, and it is not a drop-in replacement?Thanks!

author: coromonadalix
author_rank: Super Contributor
timestamp: July 28, 2018, 02:48:51 am
content: after checking the rds and the bvdss, i would check the input and output capacitance's, in audio applications i would not bother too muchBUT i would check for similar one, with the integrated diode on drain and source pins, the rds would be my main concern

author: oPossum
author_rank: Super Contributor
timestamp: July 28, 2018, 02:53:08 am
content: IRF3205Replace all MOSFETs in the power supply, not just the blown ones.Check all gate resistors.Check gate drive waveform before installing new MOSFETs.Use a current limited supply for initial powerup.

author: denimdragon
author_rank: Regular Contributor
timestamp: July 28, 2018, 02:59:59 am
content: Quote from: coromonadalix on July 28, 2018, 02:48:51 amQuote from: oPossum on July 28, 2018, 02:53:08 amThat good news. I can source these locally. Thanks guys.
Hp 6227B power supply smoking - Page 1
Forum section: electronics / repair

author: Applemac
author_rank: Regular Contributor
timestamp: July 16, 2018, 02:40:23 pm
content: I plug in my Hp 6227b today and noticed it was smoking. After switching it off and taking a look noticed burn marks on R8 on Master crowbar board. Was wondering if amyone had any ideas? Nothing was attached to the outputs as I was doing the manual startup checks.So i removed both the master and slave board snd switched on again, no smoke this time. As the R8 on the masyercrowboard was orginañly smoking this leads me to believe that something is wrong on the master boad causing the smoking of the r8 resistor on the master crowboard.

author: Specmaster
author_rank: Super Contributor
timestamp: July 17, 2018, 06:38:29 am
content: Quote from: Applemac on July 16, 2018, 02:40:23 pmSounds like the circuit is seeing over voltage so the crowbar is trying to clamp it down. I'd check the circuitry prior to the crowbar.

author: Applemac
author_rank: Regular Contributor
timestamp: July 24, 2018, 02:51:26 pm
content: Hi Ive checked the 20 volt regulated rail that goes to the crowbar. But testing test point 33 is less than 1 volt when it should read +20 volts. Made this test without the master or slave boards plugged in. Still need help diagnosing the problem, this is my first repair so any help is well appreciated.

author: MaxFrister
author_rank: Regular Contributor
timestamp: July 24, 2018, 03:29:43 pm
content: This is not really a beginners repair. You might want to put it aside and work on simpler things for a while. Here is what I suggest#1 Read about power supplies and crowbars (Art of Electronics 2nd ed).#2 Figure out how to test caps, transistors, and triacs#3 Make sure you understand the safety risks of working on high-voltage electronics.#4 Make a simple linear power supply including a crowbar# 5 and then try to find someone local to help.Perhaps more helpfully, the main filter caps are probably bad. I always begin these kinds of repairs by checking the (internal) power supplies.The crowbar should not have fired without a load on the machine. That probably means that the output was overvoltage. That implies something upstream has failed, maybe a pass transistor.Be aware that once the crowbar fires, it can take other things with it (check the pre-regulator triac if it has one).

author: Applemac
author_rank: Regular Contributor
timestamp: July 24, 2018, 09:39:38 pm
content: Thanks for the info, let me restate things im not a beginner to electronics its just my first But I will heed your advice.

author: bd139
author_rank: Super Contributor
timestamp: July 24, 2018, 11:22:52 pm
content: Check VR2 isn’t short. Had a shorted Zener in an HP supply a couple of weeks back. Also the filter caps as already mentioned. These are definitely EOL in these supplies.

author: Applemac
author_rank: Regular Contributor
timestamp: July 25, 2018, 07:28:59 am
content: Thanks for the info, let me restate things im not a beginner to electronics its just my first repair, I will heed your advice.
How to repair a USB flash drive - Page 1
Forum section: electronics / repair

author: flasonsmts
author_rank: Contributor
timestamp: July 24, 2018, 06:30:13 am
content: Most people has a USB flash drive in hand, and used it frequently in daily office work, And they will meet many problems when using the USB flash drive, But how to fix the USB flash drive when it meet problem, the USB flash drive need the software to repair, you can download the software from the following website and repair you USB flash drive:http://www.flason.com/download

author: borghese
author_rank: Regular Contributor
timestamp: July 24, 2018, 06:49:41 am
content: You do not specify which problems can be repaired by software; definitely not problems due to faulty hardware.

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2018, 07:16:50 am
content: As if they fail often (in hardware) anyway... if anything, flash drives have proven to be remarkably resilient.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: July 24, 2018, 09:54:38 am
content: if you were familiar the production of flash memory, you would know, that only the junk quality flash chips end up in sticks; first grade chips in sticks you maybe find in expensive high density brand sticks, but not in the department store grade sticks for 5 bucks

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2018, 04:37:10 pm
content: And even those have proven to be quite resilient.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: July 24, 2018, 05:43:42 pm
content: then I should throw out the car radio; supposedly only reading the sticks, I already had to throw the third

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2018, 09:41:12 pm
content: Really?!? My oldest flash drive is from around 2001 and I’ve never had one fail, ever.
JBL Sound Bar SB300 remote - Page 1
Forum section: electronics / repair

author: sairfan1
author_rank: Frequent Contributor
timestamp: July 24, 2018, 04:47:04 pm
content: Hi,I have a JBL SB300 sound bar, and i lost its remote, i tried to find on ebay but this model is not available, i tried my luck by buying compatible models SB100, SB250 and SB350 they do not work with it at all.My minimum requirement is that if i could control volume, i tried to find remote codes online so that if i could find codes and develop my own, but again no luck.Can someone help me what else i could try.Thanks.

author: keymaster
author_rank: Regular Contributor
timestamp: July 24, 2018, 08:41:01 pm
content: did you find this on ebay??(https://www.ebay.com/itm/Replacement-Remote-for-JBL-93040000260-SB300/111089779192?hash=item19dd7781f8%3Ag%3AUrcAAOxyCSRSFXCJ&_sacat=0&_nkw=JBL+93040000260&_from=R40&rt=nc&_trksid=m570.l1313#shpCntId)there is on amazon too.(https://www.amazon.com/Replacement-Remote-Control-93040000260-SB300/dp/B00CMVTDYE)
JBC DME bricked during firmware update - Page 1
Forum section: electronics / repair

author: gaminn
author_rank: Frequent Contributor
timestamp: July 24, 2018, 07:44:07 am
content: Hi,I tried tu update firmware of my DME station (program version 9996967).1) I formatted my usb flash drive with FAT32 system.2) I downloaded 8886133.jbc and 8886238.jbc files to my flash drive from jbc website3) I connected flash drive to DME a initiated firmware update.4) It started updating firmware. After a while DME restarted. I was prompted to calibrate touch screen and to do calibration challenge.5) Update process continued and then DME displayed An error ocurred during process (UM3).Now, after turning it on, DME displays JBC logo and then black screen forever. All tools connected are heated when removed from stands. I can see my DME in JBC Stations Updater 3.25.9.0 with program version 8886131 and status "Not updateable".Anyone with any experience in unbricking JBC?

author: gaminn
author_rank: Frequent Contributor
timestamp: July 24, 2018, 03:28:30 pm
content: JBC technical support was able to provide instructions how to recover bricked DME. I formatted my USB drive using FAT16, created folder called "recovery" and loaded it with firmware files. After that the station was able to perform firmware upgrade.
How to apply uA current to test analog meter? - Page 1
Forum section: electronics / repair

author: dave356
author_rank: Contributor
timestamp: July 21, 2018, 01:49:30 am
content: I have a few analog meters that I need to check and verifyfor full scale swing. Some of the meters have a magnetic shuntattached to the side, some don't. If I can adjust it, I will..What do I need to put together to apply 200ua into a 1000ohm meter.School Me!!

author: Ohm_My
author_rank: Contributor
timestamp: July 21, 2018, 03:08:55 am
content: Hello Dave,Here is a YT video that should cover what you would like to achieve. There is also a companion video for this as well worth looking at.Good luck.

author: floobydust
author_rank: Super Contributor
timestamp: July 21, 2018, 03:37:07 am
content: Never connect the meter directly to a power supply, it's too easy to peg and damage. I use a series resistor of 1k-10k and an adjustable bench power supply.

author: dave356
author_rank: Contributor
timestamp: July 21, 2018, 03:46:06 am
content: Thanks ohm-my,Just what I was looking for.Very educational

author: dave_k
author_rank: Frequent Contributor
timestamp: July 21, 2018, 05:36:18 am
content: Quote from: dave356 on July 21, 2018, 01:49:30 amOhm's Law. You would use Ohm's Law.V = I*R, or 0.0002*1000 = 0.2V.Want to drive it with a higher voltage? Figure it out...

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 23, 2018, 11:40:14 am
content: I would put a 10K linear pot across a low voltage adjustable DC power supply, starting with a very low voltage (eg. 1 V). From the wiper, connect a 1K high precision resistor (1% or less) in series with the meter, and other terminal of meter to bottom of pot. Wind up the pot until the meter reaches full scale deflection. Wind up the supply if needed. Measure the voltage across the 1K resistor. The meter current is Im = Er / 1000. Measure the voltage across the meter, the meter resistance is Rm = Em / Im.Make sure the meter is oriented in its intended operating position. If it will be in a steel case, or will have nearby iron, mount it in the case. Check the zero adjustment. These factors influence the full scale reading.
Fluke 87 III repair - Page 1
Forum section: electronics / repair

author: Beer Lover
author_rank: Newbie
timestamp: July 19, 2018, 05:08:20 pm
content: Hi all,I have purchased broken Fluke 87 III multimeter, hoping it would be an easy fix (blown fuse...).mA range fuse is blown (as the seller said), but there is more!All measurements show lower values than expected.Ohm range shows 18.28Kohm without anything connected.There are traces of someone soldering in the trouble fuse area, but nothing seems out of order.Without knowing what resistor (and other) values should be there, I have no chance of figuring it out without helpThank You in advance,Beer Lover

author: pelule
author_rank: Frequent Contributor
timestamp: July 19, 2018, 05:46:10 pm
content: I recommend first to download the 87-III service manual. It may help to find your way to soving the problem.https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwj5rYjZ26vcAhUEzKQKHb-XA-0QFggoMAA&url=http%3A%2F%2Fassets.fluke.com%2Fmanuals%2F8xiii___sieng0200.pdf&usg=AOvVaw3oiaXvcZlX2QslG1LulfF2/PeLuLe

author: pelule
author_rank: Frequent Contributor
timestamp: July 19, 2018, 05:48:33 pm
content: That thread may help also...https://www.eevblog.com/forum/metrology/fluke-87-iii-full-service-manual//PeLuLe

author: retiredcaps
author_rank: Super Contributor
timestamp: July 19, 2018, 08:07:14 pm
content: Quote from: Beer Lover on July 19, 2018, 05:08:20 pmThe input protection is likely bad.Check the PTCs, MOVs and fusible resistor. I have written about testing all 3 in various Fluke broken/fix/repair threads.QuoteClear focused pictures attached would help us help you.

author: Beer Lover
author_rank: Newbie
timestamp: July 19, 2018, 08:28:27 pm
content: Thank You pelule and retiredcaps.Will check tomorrow, now that I have schematics(not that I claim I can understand anything)Someone has done some soldering/desoldering in the input protection area,I mean there are flux residue around trough-hole components,and looks like one leg of smd bridge-rectifier was lifted, then resoldered...I'll keep You posted for sure

author: Beer Lover
author_rank: Newbie
timestamp: July 20, 2018, 02:12:39 pm
content: Update:Thermistor reads 1.17 Kohm at ~25CVaristor RV1 reads 10Kohm, RV2 reads 7.7Kohm

author: retiredcaps
author_rank: Super Contributor
timestamp: July 23, 2018, 04:31:55 am
content: Quote from: Beer Lover on July 20, 2018, 02:12:39 pmPTC ok.RV1 and RV2 are bad. Remove both and meter might work fine. Test with low voltage like 1.5V AA cell and try some resistor values to make sure 87 III works.If meter works fine, replace both varistors. Other threads have suggested digikey/mouser proper replacements.
component_Kikusui 16-10A - Page 1
Forum section: electronics / repair

author: anupong1983
author_rank: Contributor
timestamp: May 20, 2018, 01:06:52 pm
content: Hello All,I'm hoping someone out there can give me a bit of insight into this. I'm looking at a component part number 812 017 or 812 105 of Kikusui PAN series power supply.Where can I buy these part number and kindly advise if you know the part number is replacement?Hope anyone can help to find out this case, I will so appreciate.Thank you so much.Anupong

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 20, 2018, 03:31:48 pm
content: Hi!These devices you require are AD812 rail–to–rail low–voltage op–amps in 8–pin SOIC packages, datasheet readily available!The devices themselves should be available from Farnell, Digi–Key or Mouser!Any other problems could be down to the other two flat–pack devices, which are standard ICL7107 3.5 digit a/d converter and display driver DVM chips!Check your positive supply on pin 7 of each AD812 and negative on pin 4 before getting too bogged down, remember also the '7107 DVM i.c. also needs a negative supply on pin 26 as well as +5V on pin 1!If you've got the model number there might be a schematic to be had, but I suspect one of the AD812s will be for voltage control and the second for current–limit control!Chris Williams

author: anupong1983
author_rank: Contributor
timestamp: May 21, 2018, 03:36:45 am
content: Hi CrisThank you so much for your kindly.The failure symptom of my Kikusui PAN16-10 is;The display's voltage and current (VM and IM) are not stable, very hard to set value (display value always running) but the output is stable (measured by DMM).Please share if you have any idea, thank you.Anupong

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 21, 2018, 06:26:08 am
content: Hi!This sounds like a fault in the V/I metering on the front–panel itself, I'll study the PSU manual and 7107 datasheet and get back to you later with fault–finding advice!Chris Williams

author: anupong1983
author_rank: Contributor
timestamp: July 22, 2018, 02:57:29 pm
content: Hi Cris,Do you have the part list and circuit diagram of Kikusui PAN16-10A?I cannot find a part number of operate switch.Kindly help if you get the fault–finding in the V/I metering on the front–panel itself.Thanks and Regards,Anupong
Replacing N-Channel MOSFET 2SK972 - Page 1
Forum section: electronics / repair

author: lowtension
author_rank: Contributor
timestamp: March 30, 2017, 09:11:17 am
content: Hello,I am trying to look for a replacement of 2SK972, found a match in a shop near me but a stp16nf06l. The 2SK972 hag diods between G and S but the stp16nf06l dosn't, does this matter ?Attached specifications of each one.Thanks

author: Ian.M
author_rank: Super Contributor
timestamp: March 30, 2017, 11:02:38 am
content: The STP16NF06L has a lower gate oxide breakdown voltage (Vgs_max), very different S.O.A, and significantly different characteristics. What's the application, what's the max drain current, drain voltage, and gate drive voltage? A partial schematic would help.

author: lowtension
author_rank: Contributor
timestamp: March 30, 2017, 01:25:40 pm
content: Hi,This MOSFET drives a Yig filter, it acts as a current driver to the coil in the yig filter, Supply to the MOSFET comes from the Power Supply with spec:24V/2A. Coil R=48 Ohm Inductance=1.2mH. For each sweep the current Changes dependent on the specific frequency, sweep can de down to 1us or up to 500sec. Hope this helps.Thanks

author: Ian.M
author_rank: Super Contributor
timestamp: March 30, 2017, 01:31:10 pm
content: So what's the schematic of the coil driver stage? What drives the gate?

author: lowtension
author_rank: Contributor
timestamp: March 30, 2017, 01:46:56 pm
content: Hello,it is driven by an op amplifier, please look at Q25 for a similar schematics, output Point is FT-. FT+ to the coil is from 24V supplyThanks

author: Ian.M
author_rank: Super Contributor
timestamp: March 30, 2017, 01:57:54 pm
content: It looks like there are clamping diodes for the gate to a +15V raiil and to the drain. The STP16NF06L is only rated for +/- 16V Vgs_max, so cannot be safely used in a circuit that clamps the gate at +15V + 1 diode drop. Find a +/- 20V Vgs_max (or greater) MOSFET . . . .

author: lowtension
author_rank: Contributor
timestamp: March 30, 2017, 02:20:40 pm
content: Thanks!!!!!

author: Bjoern
author_rank: Contributor
timestamp: July 26, 2018, 05:46:37 am
content: Does it make sense to measure voltages at the FM+ and FM- against Ground or would I need to measure the current ?I have also a problem with my YIG. I measure the following on the connector:FM- = -3.8mVFM+ = -1.2mV the resistance between FM- and FM+ is 0.48 Ohm !When I disconnect the connector FM+ measures +7.5 V (with an 139khz signal on top of the DC), this is with a span of >10Mhz. If the span is <=10Mhz the signal jumps hence the DC is unstable (coming from the analogue board)Main Coil has 13 Ohm resistance and 13V as well as 14.95 V respectivelyI cant get a signal on FM- with or without connection.Do you see any indication that the YIG is definitely damaged (too low resistance on FM?)?It seems I might have two issues, one on the YIG with FM and another with the <>10Mhz span fed from the analogue board ?Would be great to get your insides. BTW my HP is the 8590L, I attach the relevant schematics.