hybridfree/eevblog-posts huggingface dataset:
Is there any way to fix a shorted arduino? - Page 1
Forum section: electronics / repair

author: abdullahseba
author_rank: Frequent Contributor
timestamp: July 25, 2015, 05:32:09 pm
content: Is there any way to fix a shorted arduino?I shorted the GND and 5V pin together by accident GRRRR

author: pattyrice
author_rank: Newbie
timestamp: July 25, 2015, 05:57:22 pm
content: What Arduino is it?Have you checked for holes in any of the components?The on-board regulator can be replaced or the whole micro if you got the tools. Unless it is a really expensive one, it might be beyond economical repair (BER).

author: bookaboo
author_rank: Frequent Contributor
timestamp: July 25, 2015, 06:05:29 pm
content: That shouldn't actually break any decent voltage regulator. Post pics, schematic and more details if you want detailed info. But as above unless you fancy the challenge of the repair the best route may be to buy new.

author: Seekonk
author_rank: Super Contributor
timestamp: July 25, 2015, 07:58:38 pm
content: Have you tried it again after it cooled down? If regulator shot, it can also be powered externally with 5V.

author: ivaylo
author_rank: Frequent Contributor
timestamp: July 26, 2015, 06:51:25 am
content: I've done exactly that by accident and all it did was burn a trace, which you just fix with a bodge wire...

author: abdullahseba
author_rank: Frequent Contributor
timestamp: July 26, 2015, 08:56:11 pm
content: Quote from: pattyrice on July 25, 2015, 05:57:22 pmSorry Arduno MEGA 2560

author: abdullahseba
author_rank: Frequent Contributor
timestamp: July 26, 2015, 08:57:22 pm
content: Quote from: Seekonk on July 25, 2015, 07:58:38 pmI will try this

author: abdullahseba
author_rank: Frequent Contributor
timestamp: July 28, 2015, 04:12:31 am
content: Quote from: Seekonk on July 25, 2015, 07:58:38 pmThanks I tried it and it works
Where can I find a 1QF7-0067 Hybrid Input Board for my HP3478A. - Page 1
Forum section: electronics / repair

author: Swemarv
author_rank: Contributor
timestamp: July 25, 2015, 09:11:51 am
content: Hi everyone.I have been lurking in the forums for some time, and now I need your help.I have a faulty HP3478A and I belive I have pinpointed the problem to the input hybrid board. Does anyone know where I can fine a spare ?P/N is1QF7-0067 Hybrid Input Board.Thanks

author: dom0
author_rank: Super Contributor
timestamp: July 25, 2015, 10:01:36 am
content: Either NOS from eBay or from a working unit.Recalibration is necessary after replacing the input hybrid.

author: Swemarv
author_rank: Contributor
timestamp: July 25, 2015, 03:39:50 pm
content: Thanks, I finally found one on Ebay, not cheap but what do you do.Yes I am aware that the "bangoniness" (Dave quote ;-) ) will be gone with the replacement of this.
Acer Aspire 5100 (HCW51 LA-3121P motherboard) - Page 1
Forum section: electronics / repair

author: ktulu
author_rank: Regular Contributor
timestamp: July 21, 2015, 09:46:22 am
content: Hi.Got an Acer Aspire 5100 laptop with Compal HCW51 LA-3121P motherboard.It stoped during operation.The 1.2V-psu died. (+1.2VP_HT)PQ27 FET got shorted, therefore the B+ rail protection kicked in.Removing PJP10 jumper, I measure 7.3 Ohm to GND on the 1.2V_HT rail, is thisacceptable? Would Give around 165mA.C75 and C24 are good.Someone who still has this motherboard, please help me by measuring the resistance on C24. (like I said, I got 7.3 Ohm)Schematic:http://www.s-manuals.com/pdf/motherboard/compal/compal_la-3121p_r1.0_schematics.pdfThank You.

author: wraper
author_rank: Unknown
timestamp: July 21, 2015, 09:56:04 am
content: Quote from: ktulu on July 21, 2015, 09:46:22 amDon't know if this is as it should be. But something thereabouts is not extraordinary and most likely is OK.

author: ktulu
author_rank: Regular Contributor
timestamp: July 24, 2015, 04:29:38 pm
content: OK, the board is back to life again, but I have a new problem.The only FET i could find is an FDS4410, which has a Qg of 22nC instead of 8,7nC of the original SI4800BDY-T1-E3.Would this have some bad effects on performance of the PSU IC? Maybe some overheating issues?Thanks.

author: wraper
author_rank: Unknown
timestamp: July 24, 2015, 05:21:05 pm
content: Quote from: ktulu on July 24, 2015, 04:29:38 pmMost likely not. It will cause issues only if the IC, which is driving it, have an output not strong enough. 22nC is not something huge to cause issues with a vast majority of specialized controller/driver ICs. Check the driver/controller IC datasheet if worried.

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: July 24, 2015, 05:44:23 pm
content: im just about to throw one of these out in the trash! I believe its a 5100. I'd have to check when I get home from work.

author: ktulu
author_rank: Regular Contributor
timestamp: July 24, 2015, 08:32:30 pm
content: QuoteIf the board is out of the case, please measure the resistance across C75 or C24. They are on the opposite side of where the CPU is, just near the fan hole. (black tantalums)ps. I've just noticed, that on the board the FET was actually AO4468, not SI4800BDY-T1-E3 as on the schematic.

author: wraper
author_rank: Unknown
timestamp: July 24, 2015, 08:38:09 pm
content: Quote from: ktulu on July 24, 2015, 08:32:30 pmJust don't forget that with and without CPU, this resistance most likely will be different. Also there will be different measurements depending on multimeter as you are passing current through the semiconductors. But as your board works, I assume it is completely OK.

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: July 24, 2015, 11:36:24 pm
content: well, its not out of the case, since its the entire laptop. its a 5004WMLI model.
Li-ion battery pack question (did cut a hole in a li-ion pack protective cover) - Page 1
Forum section: electronics / repair

author: Hagis2k
author_rank: Regular Contributor
timestamp: July 20, 2015, 10:32:34 pm
content: Hi well i was replacing the panel in a siemens qv830 tablet that i bought for $10 but while i triedto remove the battery pack my knife blade punctured the "protective aluminum/plastic film" and i smelleda strange odor like metallic/sweet first i didnt take it to serious so i just sealed it up with some tapenothing bad did happen in hours but i could feel that smell during charging so i took the decition toremove the battery and trash it.How do you remove these batteries that are stick to the rear of the display with double sided tape/adhesivethe easiest way? because i removed a battery like the way above a month ago with no problems but i guessmy blade was dull and i just changed the blade to a new one.It is about the same as this:http://www.ebay.com/itm/3-7V-6000-mAh-Polymer-replace-Li-Battery-LiPo-For-GPS-PSP-ipod-Tablet-PC-3691155-/181645781560?pt=LH_DefaultDomain_0&hash=item2a4aeeaa38I just feel like it is not advisable to use that pack when you can feel the odor.

author: Rasz
author_rank: Super Contributor
timestamp: July 21, 2015, 01:57:14 am
content: whats a small fire among friends, right?use plastic tools

author: eas
author_rank: Frequent Contributor
timestamp: July 21, 2015, 11:51:19 pm
content: Plastic tools, and maybe a hot water bottle to heat the backside of the case to make the adhesive release more readily.

author: poot36
author_rank: Frequent Contributor
timestamp: July 23, 2015, 05:14:34 am
content: You can also try using liquid label remover to soften the glue (Goo Gone etc). Just slightly lift one side of the battery and put a small amount of the liquid between the battery and case and leave some pressure on it to help it keep coming off and use gravity to your advantage to help the liquid keep flowing onto the freshly released glue.

author: amyk
author_rank: Super Contributor
timestamp: July 23, 2015, 06:31:27 am
content: ^ That might also soften the battery casing, with similarly bad results.A mild amount of heat is usually the best solution; failing that, a sharp, thin blade and careful work can also be fine.

author: Hagis2k
author_rank: Regular Contributor
timestamp: July 23, 2015, 09:45:09 pm
content: Yes lesson learned not to use a sharp knife, better to use plastic knife and something to lift the battery pack up slightly and maybe use the hot air to soften then glue

author: mikerj
author_rank: Super Contributor
timestamp: July 24, 2015, 07:45:18 am
content: Quote from: amyk on July 23, 2015, 06:31:27 amIt's rather unlikely that glue remover is going to soften aluminium. It might cause problems with some plastics within the device though.
ASUS 5PKR - GPU suddenly stopped, won't detect anymore - Page 1
Forum section: electronics / repair

author: Yansi
author_rank: Super Contributor
timestamp: July 22, 2015, 02:56:27 pm
content: HiI've just encountered a strange fault in my PC. I've been working and suddenly, the LCD went black. So I was about WTF and after a little poking (thought cable has fallen out - which haven't), I've restarted the PC. And it only beeped at me. It beeped me (1 long 3 short), there is no GPU in there.So fine, opened the case, looked at the GPU (nVidia 8500GT I think). Was quite hot (only passive heatsinking), but not hot enough that I could say it overheated. (but who knows).Okay, the GPU is probably kaputt gemacht. Because neither it worked after it cooled down completely. So I've taken another one. But what the hell? It doesn't work either. So I've removed some other PCI cards and tried to insert it into the second PCIex slot. It doesn't work even there. Just again, it furiously beeps at me, that there's no GPU. Neither of the two PCIex slots neither of the two different GPUs work.Now, I have an old crusty S3 Virge (without the metal frame - lost somewhere) inserted into standard PCI and having "fun" with 800x600x4bpp (=16 colors).No clue what the problem is, neither what happened to it. What do you suggest to do or test? Is it a SW or HW fault?Already been in the BIOS. Haven't seen any options related to PCIex.Thaks for your help!

author: poot36
author_rank: Frequent Contributor
timestamp: July 23, 2015, 05:04:46 am
content: Something related to both of the pcie slots is bad. Test that they are getting the correct power on the appropriate pins (look up the pcie pinout). If that passes check for buldging capacitors on the motherboard and if you find any replace them. Also try reseting the cmos and check the voltage of the cmos battery. If that still does not fix the problem try updating the bios. Also check all voltage regulators and mosfets on the motherboard for shorts or other damage. If it still does not work check that the power supply does not have to much ripple on its outputs. You can also try running the video card in pcie 1x mode by covering up all of the pins that would not normally be on a 1x card with a piece of paper in a U shape over the video card connector. You can also remove the end stop of a 1x slot on the board with some cutters and place the 16x graphics card in the 1x slot and see if it works. If it still does not work your last resort would be to reflow the solder balls under the chip or chips that control the pcie slots using hot air and liquid flux or flux you can melt into liquid. Other than that you will most likely have to replace the motherboard.

author: wraper
author_rank: Unknown
timestamp: July 23, 2015, 06:40:04 pm
content: Where did you get that second GPU and what it is? I'd put those GPUs in the different PC first, both of them might be just dead. 8500GT is from the generation of nvidia chips with defect in construction, which made them prone to sudden death, especially with weak cooling.
Repair  3458A Error 209: Hardware Failure: Timeout – Unable to Read  and Error 1 - Page 1
Forum section: electronics / repair

author: doangiau3i
author_rank: Newbie
timestamp: July 23, 2015, 01:38:54 am
content: HiI have three A3 board A/D Converter and Inguard Logic Assembly (03458-66503 board) in Agilent 3458A. If they are used, they have errors: “Error 209: Hardware Failure: Timeout – Unable to Read” and “Error 114: Multislope Rundown Conversion”. I want to repair them. Who have solution for the described problem or repair them? Please contact with me by email doangiau3i@gmail.com. Thank you very much.
Wouxun KG-UV2D & KG-UV3D Fix - Flash Repair - Page 1
Forum section: electronics / repair

author: sburrell
author_rank: Newbie
timestamp: July 22, 2015, 06:28:36 pm
content: In trying to keep these out of the trash can I posted a how-to and video on repairing these radios. The stock flash chips wears out and its an easy fix.Article and Youtube video.http://www.shaneburrell.com/?p=1082

author: GreyWoolfe
author_rank: Unknown
timestamp: July 22, 2015, 07:38:23 pm
content: Nice. I am going to bookmark the video just in case someone in the club needs help. I have hot air so should be an easy fix.

author: sburrell
author_rank: Newbie
timestamp: July 22, 2015, 07:49:37 pm
content: Feel free to share. You can get the IC off with cutters as it is a leaded surface mount you just have to be really careful not to tug on a trace. I'm sure tons of these have already went into the trash and hopefully this saves a few.
Analog Discovery USB connector repair - Page 1
Forum section: electronics / repair

author: eriklidgren
author_rank: Newbie
timestamp: July 21, 2015, 09:23:46 pm
content: Thought I'd share this in case it's useful to someone else.I bought a broken Analog Discovery on ebay that was described as not recognized by the computer anymore. After opening the case the problem is pretty obvious. The traces for USB D+/D- have sheared off, the traces for 5V and gnd connect towards the front of the connector so they are ok. After bridging the gap on D+/- with some solder it works again. I fixed the the connector in place with some epoxy, so hopefully it won't bend as much and crack the solder bridges.
Tektronix 314 service manual  - Page 1
Forum section: electronics / repair

author: BFX
author_rank: Frequent Contributor
timestamp: July 20, 2015, 09:12:36 am
content: HiI need service manual for Tektronix 314.I found schematic in few png files but complete manual would be better.Thx for any suggestions.

author: BFX
author_rank: Frequent Contributor
timestamp: July 20, 2015, 07:19:16 pm
content: Ok I got itif anyone need it here ishttp://eternal.sk/hamphoto/TEK_314_SM.pdf

author: Shock
author_rank: Super Contributor
timestamp: July 21, 2015, 08:50:23 am
content: Nice, I have one as well. Let me know if you have any other manuals or the catalog etc.
SMPS short - Page 1
Forum section: electronics / repair

author: Rachie5272
author_rank: Regular Contributor
timestamp: July 20, 2015, 05:52:34 pm
content: I'm trying to fix the power supply of an LCD television. When I first plugged it in, it went *poof*, letting some magic purple smoke out, and blowing the fuse. I replaced some FETs, diodes, the bridge rectifier, and the series NTC resistor. There's still a short somewhere though, and I can't find it.A light bulb in series with the mains glows at full power, but even when passing 100 Watts through the shorted component, nothing heats up save the NTC. The voltage on the main caps reads only a couple volts at this point.I'm not sure what to try next. The rectifiers seem fine, along with everything else I test. I know a couple secondary caps are bulging, but they aren't likely to cause these problems. Any ideas?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 20, 2015, 06:08:06 pm
content: If nothing else, you can use the voltmeter while it's sinking current, try to find the point with the least AC/DC voltage drop (as the case may be). Or track the voltage drop along traces (in the <1mV range, so you need a sensitive meter to do this).Which one's the NTC, the black thing? What's under heatshrink near the input? MOV?There shouldn't be very many things connected to the DC link, so keep checking. Guessing, besides the switching transistor and transformer, there's a smaller DC-DC chip in there, providing standby power. And the line filter stuff. It's also possible it tried to start up, then failed again, for the same reason it did originally (but without whatever emitted the "purple" smoke last time).Heh... the "Pb Free" symbol looks like undies...Tim

author: djQUAN
author_rank: Frequent Contributor
timestamp: July 20, 2015, 06:28:34 pm
content: It looks like a power factor corrected SMPS.I usually start by removing the diode bridge. This lets me know right away if the short is in the AC side or DC side.It will be pretty easy to find in the AC side but in the DC side, you start removing the main switching mosfets to see if it is one of those that is causing the problem and so on.Once you clear them out, then you look at the gate drivers and then the secondary side.

author: Rachie5272
author_rank: Regular Contributor
timestamp: July 21, 2015, 05:26:47 am
content: Yes, the NTC is the black disk in front of the bridge rectifier, and the greenish heat shrinked item is a MOV.I've made some progress. I removed the secondary fuse for the high voltage CCFL driver, and the light went out. I'm mapping out the circuit now, but the problem is almost certainly in this section.Update:One of the small ICs on the bottom was causing the trouble. It nearly unsoldered itself from the heat.
Clearing error logs on Tek MSO DPO 3000 series. - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: June 08, 2015, 10:36:38 am
content: Hello,Does anyone know how to clear the error logs on DPO or MSO 3000 series of scopes?I have an MSO3034 that has a number of front panel errors from 2010 that I'd like to clear.Looking through the firmware, there are these commands::ERRlog:FIRst?:ERRlog:NEXt?Those are obvious...:ERRlog:FILLDon't know what this one does - when I tried it, didn't seem to do anything.There does not appear to be a :ERRlog:CLEar as is present on some older generation Tek scopes.Tried it anyway, but it didn't do anything.Thanks.Jay

author: Jwalling
author_rank: Unknown
timestamp: July 25, 2015, 11:04:32 am
content: So, I think I could probably find the errorlog if I could gain access to the filesystem via telnet.Looking through the version 2.40 firmware from Teks site.Inside the image is the actual firmware in a file called filesystem.tar.gzIn the directory /etc/init.d is a file called rcS, is the following bit:# We no longer start up the micro telnet daemon for security reasons.##/usr/share/tek/utelnetd -dI could modify this to enable telnet, but utelnetd does not exist anywhere in the file system so Tek must have removed it at some point.Oldest firmware on Teks website is 2.31, but this firmware does not have the telnet daemon either.If anybody has some older firmware they could take a look at, perhaps it was in earlier versions?Jay
Repair bricked Rigol DS1052E - Page 1
Forum section: electronics / repair

author: Zaq
author_rank: Newbie
timestamp: June 13, 2015, 09:18:34 pm
content: Can some one help me out to get my Rigol DS1052E working again?Did the 100MHz hack, that worked fine.Than i want to upgrade firmware and the scope is compleetdead.Only white screen, nothing else.Can some one give me instructions what to do.I dont have a jtag op external programmer.With regards,

author: bigone5500
author_rank: Contributor
timestamp: June 14, 2015, 01:21:22 pm
content: I found this thread:https://www.eevblog.com/forum/blog/the-dark-side-of-the-rigol-hack-bricked-scope-how-to-fix-it/Quote from: drieg on September 28, 2010, 09:14:31 am

author: Zaq
author_rank: Newbie
timestamp: July 18, 2015, 06:44:57 pm
content: I got in contact with Drieg.Sent the main board to him and he repaired it verry well.I'm verry happy to have a working scoop again.Drieg thank you verry much.
Tektronix 2225 Channel 1 Position knob dislodged - Page 1
Forum section: electronics / repair

author: Franz Zinn
author_rank: Contributor
timestamp: July 18, 2015, 03:16:38 pm
content: Hi,My Tektronix 2225 channel 1 position know has come out. It is clearly not broken, and neither is the socket for it on the corresponding pot of the front panel board. But it is turning out to be very hard to put it back in place. Is there a trick to doing this ? I have done my best of taking note of the shape of it and the socket and carefully aligning when trying to push it back.regards

author: miguelvp
author_rank: Super Contributor
timestamp: July 18, 2015, 04:25:13 pm
content: There might be an allen screw that you need to loosen and later tighten when the knob is back in place.Do not force it in.

author: Franz Zinn
author_rank: Contributor
timestamp: July 18, 2015, 05:11:54 pm
content: Upon further investigation I found that the knob was actually broken. The knob is supposed to have to locking arms but one is missing. Sucks ! got to find a spare now (part number 366-0636-00).regards

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 18, 2015, 05:35:49 pm
content: Here's a place that lists them, at least, but they seem to be sold out. You might give them a call anyway...http://www.sphere.bc.ca/test/tek-parts/tek-knobs.html
yamaha rx-v471 reciever won't power up. - Page 1
Forum section: electronics / repair

author: pawill
author_rank: Newbie
timestamp: July 15, 2015, 02:36:45 am
content: I have a Yamaha rx-v471 reciever that won't power up. Nothing happens when I press the power button. I have the 5 volts and the 3.3 volts on the power supply board. I can't find a service manual or find out how to put in diagnostic mode. Any help would be appreciated.

author: BennVenn
author_rank: Regular Contributor
timestamp: July 15, 2015, 02:44:46 am
content: Looking at the model on google images I had a similar model with the same fault about 3 yrs ago. There is a system reset IC that monitors the main system voltages. All measured correct however the IC was still triggering shutdown. From memory there was a cap attached which delayed the shutdown long enough for the supply to come up to voltage. This cap went bad and replacement fixed the issue.Initially it would turn itself off when it heated up, then it would do it when cold, then it just wouldnt turn on. If your symptoms are similar, try looking at that.

author: mzacharias
author_rank: Frequent Contributor
timestamp: July 18, 2015, 03:18:41 pm
content: Starting Self-Diagnostic Function: While pressing the “TONE CONTROL” and “INFO” keys, press the "POWER" key to turn on the power.You may see a diagnostic screen appear, perhaps only briefly. Be prepared to write this information down and post back.
Repairing/Improving Alesis M1 MK2's - Page 1
Forum section: electronics / repair

author: james2k2
author_rank: Contributor
timestamp: July 17, 2015, 08:28:41 am
content: I'm not sure if it's been talked about here before, but I also know Dave's love for bad caps, and guess what - these units are filled with bad caps.Basically, the power supplies on these are prone to failure and highly susceptible to surges/spikes. The great thing is that they are an easy fix.I'm recapping both the problematic caps, and the large AC filter caps (JunFu brand). I'm also replacing a couple of power resistors with metal film instead of carbon film that they are now due to heat (my research suggests these would be better for handling higher temperatures).I've attached some photos of my intentions. My only problem is sourcing replacements for those big AC caps. Currently, they are 200V 390uF 105deg. I have found some Samwha, but at £5.30 (Around $8) a piece I can't justify replacing working caps for the sake of it. So, as I understand the voltage doesn't matter as long as it's equal or greater? But what about the capacitance? Any suggestions for a good replacement cap for these? I'm willing to spend about £1 per cap ($2 ish).In the photos:1 - 100Ohm 1W 5% (To be replaced with a 100Ohm 2W 1%) - Cracked and discoloured due to heat build up2 - 390uF 200V 105deg (Need help with these) - no problems yet, but would like to replace3 - 2x 47K 2W 5% (To be replaced with 47K 2W 1%) - these build up heat causing the cap in 4 to dry up4 - 220uF 35V 105deg (To be replaced with a Panasonic 220uF 50V where its 105deg rating will actually be true!). I will also use some heatshrink around the legs and raise it from the board slightly for extra protection.

author: SeanB
author_rank: Super Contributor
timestamp: July 18, 2015, 10:26:35 am
content: Use 470uF 200V units, same size and within the +50% tolerance. Samwa is only marginally better than JunkWoe cap in any case, you will be replacing again in under 5 years.
Onkyo HT-R670 help - Page 1
Forum section: electronics / repair

author: ripnet
author_rank: Newbie
timestamp: July 17, 2015, 03:35:54 pm
content: Hi,I have a receiver that blew a cap (C6044). I replaced it with another and it blew immediately. Any thoughts on what I should do next? I'm thinking of sucking Q6034 and Q6044 out and testing those next.Any help would be appreciated. Attached is the circuit diagram I managed to find online. C6044 is just right of center.Thanks

author: mij59
author_rank: Frequent Contributor
timestamp: July 17, 2015, 04:01:00 pm
content: Also check R6084, Q6054, R6104, Q6064, R6094 and R6074.May be something like 100 V across the cap.Pictures may be helpful.

author: ripnet
author_rank: Newbie
timestamp: July 17, 2015, 04:16:10 pm
content: Quote from: mij59 on July 17, 2015, 04:01:00 pmWhat pictures would you like? I have a clip of the PCB layout attached here.

author: mij59
author_rank: Frequent Contributor
timestamp: July 17, 2015, 05:17:57 pm
content: Pictures of the actual pcb would be nice (both sides)

author: mzacharias
author_rank: Frequent Contributor
timestamp: July 17, 2015, 10:38:22 pm
content: 1. Bad output transistors.2. One or more base current limiting resistors. (You can't really have enough DC voltage across that cap unless the BE junctions and/or R6084 or R6094 are open.)3. I would seriously check Q5044, Q5034, and the associated 100 ohm resistors R5164 and R5174.4. The bias transistor Q6014 probably didn't survive either. Not sure about Q6004.
HP Switch 3101-1720 - Page 1
Forum section: electronics / repair

author: fivefish
author_rank: Frequent Contributor
timestamp: July 16, 2015, 06:55:39 pm
content: HP Switch 3101-1720eBay sellers want $15 (incl. shipping) for this. Can anyone recognize this switch and happen to know it's brand or a compatible model?I'm fixing power switch on an HP 8012B Pulse Generator.

author: retrolefty
author_rank: Super Contributor
timestamp: July 16, 2015, 07:12:34 pm
content: Pay the man his money. Too many things that could waste a ton of time trying to find a sub.

author: fivefish
author_rank: Frequent Contributor
timestamp: July 16, 2015, 07:17:21 pm
content: LOLI know... it's just his switch price is 20% of the cost I paid for this working HP Pulse Generator. I just may have to bite the bullet.

author: vtp
author_rank: Regular Contributor
timestamp: July 16, 2015, 08:06:08 pm
content: ITT Schadow (now C&K) NE-18 series. Available from for example Mouser.

author: fivefish
author_rank: Frequent Contributor
timestamp: July 17, 2015, 03:52:01 am
content: Quote from: vtp on July 16, 2015, 08:06:08 pmAwesome! Thank you very very much!Brand new and cheaper too. Will get this on my next order from Mouser!Thanks again!
power supply circuit on the HP 54524A - Page 1
Forum section: electronics / repair

author: 1kostik1976
author_rank: Contributor
timestamp: July 15, 2015, 05:00:00 am
content: Hi everyone. someone has the power supply circuit on the HP 54524A.

author: dom0
author_rank: Super Contributor
timestamp: July 15, 2015, 11:12:08 pm
content: If you mean the HP 54542A (or any of it's siblings) then... well, as far as I know all the PSUs in that series were supplied by external contractors and no publicly available schematics exists. However, replacing them with other COTS SMPS is possible and has been done.

author: free_electron
author_rank: Super Contributor
timestamp: July 15, 2015, 11:42:07 pm
content: yea, those were made by delta if i got that right. OEM job.
Anyone well versed in GE / Morpho Itemiser 3? - Page 1
Forum section: electronics / repair

author: PTR_1275
author_rank: Frequent Contributor
timestamp: July 15, 2015, 09:54:36 am
content: Hi everyone,I recently picked up a bulk pallet at auction and it had 2 quite large road cases that I couldn't get into at the time of inspection. Once I won the auction and got the pallet back to the workshop, these 2 road cases had a Itemiser 3 in each of them. For those that haven't yet googled what they are, they are the drug / explosive detectors that they use at the airports. They wand you down, place the sample into the slot at the front and display if you have the presence of bad things on you.I have no use for them, but I want to get them working. They power up OK, but my first problem is the user login. No numbers that I can find on the unit have any affect on it. I can't find a useful manual (Lots of dead links promising manuals, but not). Is there anyone in the EEVblog community who has used these units, serviced them or knows anything more than the sales pitch on their website?Many thanks (Apologies if this is in the wrong spot, please move it if you feel the need)-Chris
repairing a leister triac s plastic welder with a bad control board - Page 1
Forum section: electronics / repair

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: July 12, 2015, 04:46:13 pm
content: I am attempting to fix a leister triac s [https://www.leister.com/en-nl/plastic-welding/civil-engineering/products/hot-air-hand-tools/triac-sthat had a non-funtional control board, which is potted in some sort of silicone making it impossible to troubleshoot. Does anyone have any ideas to regulate a 1600W heating element?

author: HighVoltage
author_rank: Super Contributor
timestamp: July 12, 2015, 04:57:20 pm
content: A long time ago I repaired one of these great Leister tools. The potting material was actually of soft polyurethane material and I was able to remove it completely to gain access to the components. Troubleshooting was easy then and if I remember right, it was only a broken SCR that needed to be replaced. At the time I contacted Leister and they also offered the control board as a replacement part. But this was in the USA and a long time ago.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: July 12, 2015, 07:44:16 pm
content: I guesse the potting compound could be polyurathane, all i know is it's soft and rubbery, white, and has a thin red/pink layer where it touches something else [components, wires, ect.].About getting the board from Leister, my dad sent the whole thing in to get repaired and the repair estimate was just a little less than a new unit. so i think that a new control board is out.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 12, 2015, 08:38:07 pm
content: If you send the complete tool to Leister, they will charge a premium price, but replacement parts were reasonable. It takes a lot of time and careful attention, but removing the soft potting material is your only other option. Or you build a new control circuit from scratch.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: July 12, 2015, 08:48:46 pm
content: Thanks for the tip about the replacement parts I'll look into it.Edit:found a web page with a breakdown of all the part numbers:http://www.ihshotair.com/triac-s-spare-parts-diagram
Trying to fix a broken car amp. - Page 1
Forum section: electronics / repair

author: David97
author_rank: Contributor
timestamp: June 12, 2015, 01:22:41 am
content: Hi everyone. I bought a broken soundmagus Q-150 amp for cheap. The guy didn't say what was wrong with it but I assumed that it was something like bad transistors on the output line or a faulty PSU when I bought it. When I power it on it powers up fine, and does not go into protect mode. However when speaker is connected it just ticks, like a clock. I have measured the voltage on the power supply while running and it measures a steady 32V, no sag when speakers are connected. I have also taken all of the output transistors out of circuit and they all behave as expected.excuse the dodge cap. I did that because the original was swollen, and the electronics store didnt sell 3300uf, so I put in a 4700uf instead until the right ones arrive in the mail.Because everything else is working fine, I think it has to be a issue with the preamps, or filters, something involved with the interpretation of the input signal. All the chips involved in this are getting the correct voltage. I'm not sure what to test next, but I have a feeling that it's going to get difficult without a oscilloscope.I have a feeling that a way I could test this is by hooking up a pair of headphones to the RCA output on the amp. I think that this runs through all the filtering and preamp stuff, but not sure. Then If I got sound out of this I could verify that the preamps, and all that stuff is working correctly. I'm not sure about this, so if anyone knows that would be helpfullDoes anyone know what I should be looking at next? Or any advise on what It could be? Thanks, David.

author: oPossum
author_rank: Super Contributor
timestamp: June 12, 2015, 08:54:56 pm
content: If all channels have that problem, then check the supply rails for the op-amps.If it is just one channel, then check the SMD transistors that drive the outputs.

author: Unelma
author_rank: Contributor
timestamp: June 13, 2015, 05:46:56 am
content: Check all zener diodes.

author: envisionelec
author_rank: Frequent Contributor
timestamp: July 12, 2015, 02:52:40 am
content: Quote from: David97 on June 12, 2015, 01:22:41 amThe PT2313 is a CMOS Audio Switch. It's probably dead and won't pass a signal.
Tektronix TG501 plastic latches needed - Page 1
Forum section: electronics / repair

author: mskobier
author_rank: Regular Contributor
timestamp: July 11, 2015, 08:26:39 pm
content: All,I have a Tektronix TG501 later series module that is missing the side cover plastic latches. These are the plastic slotted twist latches that are located on the rear edge of the side covers for the later 500 series modules that holds the covers in place. Does anyone know where I can locate a couple of these latches?Thanks
Help with HP 54815 oscilloscope drivers - Page 1
Forum section: electronics / repair

author: zxase258
author_rank: Contributor
timestamp: July 09, 2015, 01:32:28 pm
content: There's somthing wrong with my HP54815A scope HDD?I got a new HDD and replaced the old one?By the way?I updated the system memory from 32MB to 256MB?After that?I installed a new win2000 OS?But the problem is?How can I install the scope PCI interface card driver?I have already tried the VXI driverdownloaded from keysight 54815A driver page?But it useless?Now?I can only ask for this problem here?Is here anyone who knows about that fucking driver?Please help me.Thanks!

author: Jwalling
author_rank: Unknown
timestamp: July 11, 2015, 10:16:12 am
content: Quote from: zxase258 on July 09, 2015, 01:32:28 pmThose scopes never shipped with Windows 2000, they were Win95 and Win98. I doubt you'll ever get it to work.Jay
TEAC DV-R301 DVD No Video - Page 1
Forum section: electronics / repair

author: tazelikechickn
author_rank: Regular Contributor
timestamp: July 11, 2015, 09:12:17 am
content: Hey Guys,I have a TEAC DV-R301 that I have scored (yes, I know - pretty old school)It powers up and has all the inputs, like radio working, but had no DVD operation. I pulled it apart and figured that the laser was faulty. After having some trouble trying to find a replacement and also the price made it not worth fixing, I had a close look at the connections and discovered that they were the same as some of the early DVD players used in computers. I just so happened to have a few spare and have tried one that works. It will open, close, start and play with the computer DVD and even the sound works fine. The only issue is that I have no video. Yes, before you ask, I have the connections in the correct jacks and the sound works fine as I said. I have even tried another set of cables to be sure, but nothing!I'm wondering if the format of the computer DVD may be different. I have even copied the shorting terminal at the back and copied the connection from the TEAC DVD. I have tried several different DVDs, in case they were region related issue. Nothing. I think it may be an issue within the TEAC DVD player itself and not the computer DVD that I have hooked up to it at the moment.Any thoughts?? Any help would be greatly appreciated.Cheers
7603 Scope Total Failure - Page 1
Forum section: electronics / repair

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 10, 2015, 07:41:08 pm
content: One of my scopes just thought it would be the nicest thing to commit suicide.It started with a bit of odd flickering, then total loss of vertical control, then the horizontal, then everything flickered and went dark.With a bit of wire wiggling I managed to start it two or three times, until I thought "she'll be right" and put it back together. Died again...with no smoke or sparks, just won't turn on. Luckily, every single semiconductor (except maybe a few heatsinked FETS) is socketed.Upon inspection there are casualties, and a zapping noise. An evil...EVIL...little $0.02 2N5551 thought it was totally hilarious to short out in the circuit of a $6.67 U.S. dollars 2N5859 (causing more poppage). IDK how much else is blown, still checking parts. I'll have to take it entirely apart to get to the rectifier board. But what are the chances the blowout was contained in the PSU? And what was that zap, an arc over or a semiconductor burnout?
uCurrent repair - Page 1
Forum section: electronics / repair

author: embedded_tom
author_rank: Newbie
timestamp: July 10, 2015, 12:46:45 pm
content: A momentary loss of common sense caused the 10 ohm/0.05% resistor (R9) to fry in my uCurrent. (I was measuring a 3-cell battery pack by breaking the pack in the middle, and forgot to disconnect my scope when I reconnected the USB communication module. Dammit.)Before I order a Digikey replacement, I was wondering if anyone had the full specs for that part?Thanks.Tom

author: miguelvp
author_rank: Super Contributor
timestamp: July 10, 2015, 01:23:45 pm
content: Here is Dave's BOM:http://www.eevblog.com/files/uCurrent-BOM-Rev5-Public.pdfFrom here:http://www.eevblog.com/projects/ucurrent/
Is my inverter dead or lcd backlight? - Page 1
Forum section: electronics / repair

author: David97
author_rank: Contributor
timestamp: July 10, 2015, 11:08:30 am
content: Hi everyone. I was trying to get a lcd pannel form a old laptop to work with a cheap ebay lcd controller. I had the original inverter and hooked it into the lcd controller. The inverter has 6 pins labled VCC, NC, ENA, CTL, GND NC.When I hook it into the LCD controller I soldered VCC > 12V, GND > GND, ENA > BLON (though this means back light on?), CTL > Adj. When I power it up The back light on the lcd flicks once and then goes dead. I took a multimeter and probed it and got 12V on the supply to the inverter, 5v on ENA and nothing on CTL. I think this is normal as from what I've read the ctl pin is 0V at the highest brightness and 3.3V at the lowest.I took apart another monitor I had and tried to see weather I could get the back light to work using the inverter from the working screen.I could not get the light to work, it didn't even want to flick once.So is it safe to say that the light is dead? Or could the inverter i tested the lcd with not be matched to the bulb?Thanks.
JBC JT7750 Hot Air Repair - Page 1
Forum section: electronics / repair

author: Magicmushroom666
author_rank: Contributor
timestamp: July 10, 2015, 10:48:58 am
content: Just some info on a quick repair I just completed.I bought a JBC JT7750 hot air rework station cheap which was working, although the LCD was just displaying gibberish characters.Doing a bit of testing showed that the PIC was sending the correct initialisation steps to the LCD (for 4 bit mode) so I suspected the LCDs built in controller itself.Controller for the station is a PIC18F6621With a bit of google, the following part from RS appeared to be a good fit:http://uk.rs-online.com/web/p/lcd-monochrome-displays/5326559/RS number 532-6559Soldered in the replacement and all up and working! too easy.I suspect the other JBC products from the same range also use the same LCD.(White border LCD is original, black is the replacement)
Motorola 24A Diode Replacement - Page 1
Forum section: electronics / repair

author: warf135
author_rank: Contributor
timestamp: July 05, 2015, 07:24:18 pm
content: Hello, I'm repairing a radio that uses an SMD Motorola diode for reverse polarity protection on its power line.The diode is marked: 24A and from what I can tell, is either: 1.5SMC24AT3 or: P6SMB24AT3 I need to find a suitable replacement for this diode.Here is a pic of the blown diode:I'm pretty sure that -being used only for reverse polarity protection- its not important to get an exact match... Any Ideas?Thanks in advance!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 05, 2015, 07:29:36 pm
content: That's a TVS, not just reverse protection.Probably, anything SMB/SMC of the same specs would do; SMCJ24A is quite common. (Make sure it is not the -CA version, which is bidirectional and won't provide reverse polarity protection!)Do measure the package to verify which one it is (SMB is smaller than SMC).Tim

author: warf135
author_rank: Contributor
timestamp: July 05, 2015, 07:56:58 pm
content: Thanks for your quick reply!Service manual for radio states that it is there for reverse polarity protection no mention of TVS(and sadly no parts list in the service manual i have) I will try to measure the diode soon.Cheers!

author: warf135
author_rank: Contributor
timestamp: July 10, 2015, 08:34:22 pm
content: Hello, apologize for delay I have been unwell... Original diode is about 7mm x 5mm.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 10, 2015, 09:08:28 pm
content: 7-8mm body / overall, should be SMC then.

author: warf135
author_rank: Contributor
timestamp: July 10, 2015, 09:50:08 pm
content: Thanks, SMCJ24A ordered!
A question about MOVs / Varistors. - Page 1
Forum section: electronics / repair

author: McBryce
author_rank: Super Contributor
timestamp: July 08, 2015, 05:58:34 pm
content: Hi,As I usually only work on battery powered systems up to 48V, it's rare that I have to deal with varistors. Today I had a control unit (fish tank pump / filter controller) to fix which has 6x 230VAC outputs. Each output had a varistor across the switch contacts of the ouput relay. They are Epcos S20K275. All have infinitely high resistance when measured out of circuit, but at 230VAC they all allow the full 230V through, overriding the relays function. Removing them solves the issue, so obviously they're somehow damaged. My questions:1 - How can I reliably check this type of varistor out of circuit to know whether it's broken (without applying the 230V)2 - Only 3 of the outputs have ever been used, but all 6 varistors seem to be damaged? Was the device possibly hit by lightning, or what could have caused this?Thanks in advance for any tips.McBryce.

author: Seekonk
author_rank: Super Contributor
timestamp: July 08, 2015, 06:24:55 pm
content: I used to manufacture snubber devices. Sometimes after potting they would mix up the batches so I would have to identify what was what. For movs I had a low current voltage multiplier and looked for the voltage knee at about 1-2ma. For a 275 mov that would easily be 400V. There aren't really solution below that voltage. The voltage can change with a large surge, going up as well as down. You don't say what these are connected to. Capacitance can be several thousand pf and you may be seeing capacitance effects if these are on the switches.

author: McBryce
author_rank: Super Contributor
timestamp: July 08, 2015, 07:23:57 pm
content: The MOVs are across the common and normally open contacts of a small relay (Tyco - 24V coil, switching 230VAC). They switch AC motors (pumps and the drum of a drum filter) depending on water levels. The effect after failure is quite capacitor-like, maybe I'll connect one to an LC or ESR meter and see what they readMcBryce.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 08, 2015, 10:59:07 pm
content: You say they're letting AC through. How much? Did you measure?

author: McBryce
author_rank: Super Contributor
timestamp: July 09, 2015, 08:05:17 am
content: Here's the schematic of an output. The 230VAC is measuring correctly. At the output terminals it reads 230VAC when the relay is actuated and 190VAC when the relay is turned off.McBryce.

author: Seekonk
author_rank: Super Contributor
timestamp: July 09, 2015, 07:21:11 pm
content: If there is only a meter on the output I can easily see that much voltage being read by the meter. As I thought the problem isn't real. If it makes you sleep easier, place the MOV across the output. A much better place for it anyway.

author: McBryce
author_rank: Super Contributor
timestamp: July 10, 2015, 07:47:31 am
content: This isn't a design I'm doing, it's a commercial device I'm repairing. Moving the MOV somewhere else isn't an option. With a working MOV the voltage across the ouputs is about 14VAC when the relay is open.McBryce.
Small mains socket (case mounted) and plug recommendation - Page 1
Forum section: electronics / repair

author: owiecc
author_rank: Frequent Contributor
timestamp: July 03, 2015, 02:12:26 pm
content: Do you have any recommendations for a small plug/socket 230V rated. I will use it on a blade saw. One of the adapters needs 230V and is now connected to a wall socket. I was thinking on replacing that and taking the power from a saw unit. Current drawn by the adapter is extremely small, well below 1A.The saw is quite small and I would like to put a small socket on its case. There is also water involved in the cutting so ideally the socket should be splash resistant. Do you have any recommendations? I found a few already but they were either huge 16A rated or super expensive.

author: wagon
author_rank: Frequent Contributor
timestamp: July 05, 2015, 02:27:22 am
content: Something like thishttp://au.element14.com/amphenol-tuchel/c016-20c003-200-12/plug-panel-screw-au-3p-e-way/dp/1188985I've used them for similar jobs with success.

author: Psi
author_rank: Super Contributor
timestamp: July 05, 2015, 06:00:38 am
content: As long as that one is for mains input

author: dom0
author_rank: Super Contributor
timestamp: July 07, 2015, 05:43:48 pm
content: Hirschmann ST series? 2+PE is available and suitable for mains.

author: wagon
author_rank: Frequent Contributor
timestamp: July 09, 2015, 12:58:20 am
content: Quote from: Psi on July 05, 2015, 06:00:38 amThey are rated to 250V. Don't know about 'approval', however.
Hp 6632a error test 18 - Page 1
Forum section: electronics / repair

author: Jesset1996.5
author_rank: Regular Contributor
timestamp: July 08, 2015, 03:53:42 am
content: Hello everyone. I have a hp 6632a that has a test error 18 message on the lcd once it is turned on. I have already tried simply clearing the error with no luck. Any suggestions on what i should do to fix this?

author: MarkL
author_rank: Unknown
timestamp: July 08, 2015, 02:17:49 pm
content: Download the service manual and follow the troubleshooting section in chapter 4:http://literature.cdn.keysight.com/litweb/pdf/5957-6365.pdfThe manual lists error 18 as:CV/CC zero too high. CV or CC DAC probably defective (see Figure 4-11)It doesn't sound promising, but you won't know for sure until you work through the troubleshooting flowchart in 4-11.

author: Jesset1996.5
author_rank: Regular Contributor
timestamp: July 08, 2015, 07:18:38 pm
content: Quote from: MarkL on July 08, 2015, 02:17:49 pmThanks! I actually got it to work by using the bypass jumpers tp1 and tp2. Now i must figure out how to erase the previous programming that caused the problem I actually just got this thing at a ham swap so its previous owner must have incorrectly programmed it!