hybridfree/eevblog-posts huggingface dataset:
Agilent N3301A elelctronic load fan speed control - Page 1
Forum section: electronics / repair

author: Samogon
author_rank: Frequent Contributor
timestamp: October 14, 2017, 04:03:33 am
content: Hi,I have got used unit in pretty good shape and it works as it should, but fan is running full speed and it is really noisy.Manual says that fan can be set to lower speed if load is low. But it says nothing how to do that.On old units 66xx series one could setup fan speed by getting into setup menu depressing 0+9.But for N330x series this trick is not working.I wonder if N330x fan speed control has thermal sensor circuit to adjust speed to keep temperature in threshold.I would appreciate any input.Thank you
Request for help on a  B&K Precision 1652 Power supply. - Page 1
Forum section: electronics / repair

author: rfengg
author_rank: Regular Contributor
timestamp: October 15, 2017, 11:56:19 pm
content: Hello All,Request the forum members for help with my B&K Precision 1652 Power supply.The B&K Precision 1652 Power supply I got off Ebay has a part of the main PCB heavily charrednear R55 and R56 so much so that I cannot make out the trace connections on the top or bottom side.Also the internals seem to have been heavily modified by someone and I was left wondering if this mods were done atthe factory or during the repair attempt of the previous owner.If anyone on the forum has this power supply model, could I request few pics of the area near R55 / R56 (both top and bottom sides)so that I can rewire the traces?Also a pic of the whole main board would be helpful to determine if the mods I had mentioned were actually part of the factory installation?best regards
Changing Audio related capasitor in speakers. - Page 1
Forum section: electronics / repair

author: Bashstreet
author_rank: Frequent Contributor
timestamp: October 14, 2017, 09:39:41 pm
content: Hi I am planning to recap some old electrolytics in pair of Yamaha speakers.Looking for caps that will do well in Audio circuitWould Nichicon PW series do well as they are readily available for me.Another question i have in another pair of speakers a 100v 3.9 ?F electrolytic... and i cannot seem to find good replacement... any ideas

author: Circlotron
author_rank: Super Contributor
timestamp: October 14, 2017, 09:49:45 pm
content: For the 3.9uF electro, any film capacitor will be light years ahead. Just use several smaller polypropylene caps paralleled to get the right value. Whether the esr of the original cap was taken into account in the design of the crossover is hard to say.http://www.diyaudio.com/forums/multi-way/is the world’s best place to ask.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: October 14, 2017, 09:55:52 pm
content: Yeah i was considering polypropylene cap(s)I give it a look.

author: Gyro
author_rank: Super Contributor
timestamp: October 15, 2017, 09:58:26 am
content: This might be a bit controversial, but if you're in the mood to experement and don't mind potentially wasting a few £, pick up a pair of former soviet military hermetic 4uF PIO caps and compare them against the electrolytics and polypropylenes.eg.https://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=paper+capacitor+4uf&LH_PrefLoc=1&_sop=15Obviously you don't need to go above 160V - 300V rating.I make no 'audiophool' claims but you might prefer one or other presentation. It's a personal preference thing, there's no right answer.Edit: If you switch the search to worldwide then you can find them a bit cheaper from Bulgaria, but obviously delivery time is longer.

author: B1nary
author_rank: Contributor
timestamp: October 15, 2017, 02:42:23 pm
content: I just re-capped my IMF Reference Monitor IV Improved. After a rather tedious search I found these guys in Great Britain. Very knowledgeable and the price was half what I was being quoted out of "Toronto".http://www.falconacoustics.co.ukSend an email (on their site) to Jerry

author: Bashstreet
author_rank: Frequent Contributor
timestamp: October 15, 2017, 05:49:59 pm
content: Thx guys for the advise.I went for some NICHICON UEP caps for the 10uf and for the 3.9Uf Panasonic polys.I post results when they arrive and i have recapped.
Looking for this "I don't know exactly what" Part - Page 1
Forum section: electronics / repair

author: HardCoreElectronics
author_rank: Newbie
timestamp: October 12, 2017, 04:21:01 pm
content: I am repairing a Pioneer DJ console DDJ-SZ model (Way different than the SX model) and I have located the problem but not sure of this parts designation. Listed on the board as P702. I'm assuming it's probably P for PicoFuse maybe? Ordinarily I would expect an F# designation label.In the photo I have 2 of these on the board and the P702 measures open. The SMD# "10" to me might means 1.0 Amp or 10Amps. No other specs and I don't have a schematic. And yes bridging it out does work but it's not a "proper" repair.Anyone familiar with this one?

author: SeanB
author_rank: Super Contributor
timestamp: October 12, 2017, 06:56:14 pm
content: Looks more like it is an inductor than a fuse, probably 10nH surface mount.

author: HardCoreElectronics
author_rank: Newbie
timestamp: October 12, 2017, 07:55:11 pm
content: Makes sense it would be an inductor. I found this part 1210R-100K at Digi-Key to replace it.This part would be there to filter off RFI from other devices emitting RF near the console and probably to limit outgoing RFI from the console itself.Thanks for the second set of eyes!

author: tru
author_rank: Regular Contributor
timestamp: October 13, 2017, 06:54:13 am
content: Inductor is normally L.I think it is a 1amp fuse and P stands for Protector.See posts here:http://www.edaboard.co.uk/pioneer-pro-dj-unit-t550411.htmlScroll down to "Mark Zacharias" post, that guy has the service manual.

author: HardCoreElectronics
author_rank: Newbie
timestamp: October 13, 2017, 02:33:07 pm
content: Yes I figured thats why they put the P there also but then going looking for a fuse in that packaging (1210 / 3225) doesn't exist.The inductor i found matches the physical dimensions and footprint. Given that, it would also serve as a fuse because it's current limiting properties being so small at less than 1 Amp.My Assumption: Pioneer has used P as their designator to cover for a fusible RFI filtering component and maybe called it Protector.

author: razberik
author_rank: Frequent Contributor
timestamp: October 13, 2017, 03:05:35 pm
content: KOA Speer CCP series fuses.Or just say Playstation 2 fuseshttp://www.ps2-home.com/forum/viewtopic.php?t=3686&p=21358&utm_source=dlvr.it&utm_medium=facebook#p21358

author: mzacharias
author_rank: Frequent Contributor
timestamp: October 13, 2017, 09:33:55 pm
content: I think it would be the surface mount version of the ICP-N10 "IC protector"
Repairin Keithly 2001 - Page 1
Forum section: electronics / repair

author: rroland
author_rank: Newbie
timestamp: October 12, 2017, 07:07:58 am
content: Hello guys,I am new to this forum and I need help repairing my Keithly 2001.I tried to find case like my, here on forum, but no luck.My DMM is working cca. 1,5 - 2 minutes, than turns off and starts again (like reset).After few this cycles does not turns on any more.As I tried to repair it, I found that U629 (LM2940CT low drop 5V voltage regulator) is heating to much.This (U629), as i understood, is 5V for digital board.I did not found anything else to be heated to much except U629, not on digital neither on analog board.Can someone please help me with this.Thank you very much.

author: Shock
author_rank: Super Contributor
timestamp: October 12, 2017, 08:58:10 am
content: Heating up but providing the correct output voltage still? Where exactly does the voltage drop out?Look for input and output caps on the regulator as well as resistors or diodes that could be pulling high current. After replacing any defective components remove the regulator and power that rail from a current limited bench supply (current limited to something sensible). You can also measure resistance across that rail when the regulator is out as well for obvious shorts.If it stays up on the bench supply it's more than likely the LM2940CT, you can load test it out of circuit if you like, but it's best to replace it to be sure even if it was a cap. With caps check for C, ESR, leakage then check for electrolyte contamination on the PCB if applicable and consider replacing all caps similar to the defective one.

author: rroland
author_rank: Newbie
timestamp: October 13, 2017, 06:15:46 am
content: Hi Shock.Thank you for answer. You helped me to find failure.It was DC-DC converter who draw to much current.It is replaceable part so I will order one.Thank you ones again.

author: TiN
author_rank: Super Contributor
timestamp: October 13, 2017, 01:29:41 pm
content: If your meter old (made before 2010) - replace ALL large electrolytic capacitors, or you will end up destroying the meter. This is known issue in these meters.Some data can be foundhereand of coursehere on forum.
My SAMSUNG UA40D5030 LED TV is not powering up - Page 1
Forum section: electronics / repair

author: gauravped
author_rank: Newbie
timestamp: October 08, 2017, 04:08:48 pm
content: Hi All,I have SAMSUNG model number UA40D5030PR LED TV which I bought in 2011, working fine till September 2017.All of a sudden while watching TV, it turned off on its own. No Status LED, no backlight, and thus no picture. I tried to turn it on with Remote and both with front panel power button. It is completely dead.Upon opening the backpanel of the TV, on the power circuit board, I noticed that theFuse, marked asFP801S (250V,5 Amps,Ceramic Through Hole type)was blown. Thus, I went to hardware shop, and bought new same specification fuse and replaced it. Within 1 second of powering up the TV again, the new fuse also blew. I realized that blowing fuse is not the real cause. Something else is drawing higher current which is making fuse blow. So I surfed the internet, did some reading, and using just a multimeter to troubleshoot, I came to know thatPower MOSFETmarkedQP801S (MDF11N60 from Magna Chips) has all Gate-Drain-Source Terminals shorted. Also, one Capacitor markedCP802S (PILKOR WK113)is shorted.I can't confirm them as failed components, as I could not get the exact circuit diagram of the power board. All circuit diagrams I got online are of Power Board part number:BN44-00473AorBN44-00422Awhile my TV uses power board part numberedBN44-00473B.Can anyone provide me circuit diagram ofBN44-00473B?Also additional inputs for troubleshooting the board from experts are highly appreciated. This is the first time I am troubleshooting my home appliance.

author: orbanp
author_rank: Regular Contributor
timestamp: October 13, 2017, 01:12:16 pm
content: The "A" and "B" version boards look pretty much alike (from eBay pictures), so I think you should be fine if you have the schematics for the "A" version. There is probably only some minor difference between the versions.As for the repair, do replace the shorted components, and also do check the ESR of all the electrolytic capacitors and do replace the questionable ones.EDIT:You could also test the PS out of the TV.For safety do use an isolation transformer!Depending on the controller IC used in the PS, the PS might require some load to work! So put some external load on it, like light bulb, or power resistor.A quick search did not turn up for me the schematics of the "A" version board.If you post the schematics you will probably have more help!Good luck, Peter
Infi Vision MSO-X 4054A hanging. - Page 1
Forum section: electronics / repair

author: rtekal
author_rank: Contributor
timestamp: October 11, 2017, 05:02:32 am
content: HiI have an Agilent Infi Vision MSO-X 4054 A oscilloscope which hangs up during startup. Following the troubleshooting guide, I found that the backlight supply and the auto probe voltages are absent. Further probing shows that the NCP3064 switching regulator looks dead. Even after replacing the IC the problem persists. THere is no signal at timing capacitor pin 3. VCC is available on switch collector pin 8. Switch Emitter pin 7 is low. On /Off pin is also low.Has anyone faced / solved this problem Any help is appreciated.Regards

author: TheSteve
author_rank: Unknown
timestamp: October 11, 2017, 07:27:40 am
content: At what point does it hang?Have you connected to the internal UART to see the boot log?

author: rtekal
author_rank: Contributor
timestamp: October 12, 2017, 05:50:34 am
content: After switch on Ref, Math & Digital lights glow and stays there. No Dispaly internal / external, no probe voltages.Regards

author: TheSteve
author_rank: Unknown
timestamp: October 12, 2017, 06:24:15 am
content: Sounds like it might have a flash corruption issue like the 2000/3000 series. Have you contacted Keysight to ask if they will cover the repair? If that isn't an option you will need to connect to the internal uart to see where it is hanging in the boot process.

author: Zucca
author_rank: Unknown
timestamp: October 12, 2017, 10:00:12 am
content: Mine 3000X did not boot up once. then I cycle the power and no more issues...

author: rtekal
author_rank: Contributor
timestamp: October 13, 2017, 05:50:03 am
content: The backlight voltage & probe voltages are not coming. Are these voltages controlled by the system? How do I check the UART signals?Regards

author: rtekal
author_rank: Contributor
timestamp: October 13, 2017, 08:34:24 am
content: Keysight will not cover it under warranty. They replaced the boards of 2000 series at my workplace at no cost.regards
Mettler H15 analytical scales issue - Page 1
Forum section: electronics / repair

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 10, 2017, 08:44:14 pm
content: Hi!I recently aquired an 1962 vintage Mettler analytical balance in near perfect condition, the H15 model. It's a marvel of a swiss clockwork! it's basically and old fashioned scale with one 'pan' being constant and the other being adjusted by turning knobs that lifts and lowers different weighs BCD-style! the microgram scale is a tiny film scale on the beam of the scale projected onto the translucent front panel like a vernier. I'll put up some pictures at some point. To be fair, it's more mechanic than electrical, but I'm hoping there's someone here who's actually used/maintained one.It measures the mass up to 160 grams, down to 4 decimal places.Here's the problem: it measures wrongly! I weighed out an object (binder clip) on the modern Mettler scale in my lab, and then again on mine. It's consistently about 417 mg off on that mass.Now, I haven't done a whole series of standard weighs and made a calibration curve yet, but my initial thought is that i know it has a means of tare-ing it, this works by adding a permanent weight on one end of the beam, and indeed there are little washer-like weighs there, but if it IS in fact calibrated properly, I don't want to mess with factory calib. which is probably better than I can do anyway.What do you think? Anyone happen to have the manual for this? (or the H5 or H10, they're almost identical)thanks for the look!

author: ElektroQuark
author_rank: Unknown
timestamp: October 11, 2017, 07:21:03 am
content: I have an H20T. The manual is for the H10t/H20T models.I can scan it if you want.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 12, 2017, 03:57:53 pm
content: That would be very very helpful! especially the parts about calibrating and tare-ing!thanks!

author: ElektroQuark
author_rank: Unknown
timestamp: October 12, 2017, 04:22:54 pm
content: I checked yesterday, it's in French and Spanish. Any preference?There are a lot of images, so it could be helpful.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 12, 2017, 05:30:04 pm
content: Oh I'd much prefer french!Thanks for the help!

author: ElektroQuark
author_rank: Unknown
timestamp: October 12, 2017, 05:45:14 pm
content: I will scan it tomorrow at work.Send a PM with your email, please.
Capacitor. - Page 1
Forum section: electronics / repair

author: jheatac
author_rank: Regular Contributor
timestamp: October 10, 2017, 03:35:53 pm
content: Is this just an Aluminum Electrolytic or is it something special?Sent from my SM-G920V using Tapatalk

author: wraper
author_rank: Unknown
timestamp: October 10, 2017, 03:43:01 pm
content: Nichicon 1000uF 6.3V, HC series

author: chhrisedwards
author_rank: Contributor
timestamp: October 11, 2017, 02:01:25 pm
content: Hi, I am a beginner to electronics and I just started learning about capacitors, resistors, electronic circuits etc. So, now it’s little bit difficult me to identify this capacitor. Soon I will be here to give the exact answer.

author: Old Don
author_rank: Regular Contributor
timestamp: October 11, 2017, 03:05:37 pm
content: http://www.mouser.com/ProductDetail/Nichicon/RHS0J102MCN1GS/?qs=sGAEpiMZZMvwFf0viD3Y3SMVxP1r9x1DyOb3zgtIiZM%3d

author: wraper
author_rank: Unknown
timestamp: October 11, 2017, 03:09:28 pm
content: Quote from: Old Don on October 11, 2017, 03:05:37 pmAnd what this is supposed to mean? On the Photo there is through hole LOW ESR electrolytic capacitor, you post a link to SMT polymer capacitor.

author: Old Don
author_rank: Regular Contributor
timestamp: October 11, 2017, 08:11:47 pm
content: Quote from: wraper on October 11, 2017, 03:09:28 pmCrap, I thought I saw a SMT cap!, Forgive me if I'm wrong, but I am under the impression that a polymer cap has lower ESR than an aluminum electrolytic. Which explains the polymer link.Try this one:http://www.mouser.com/ProductDetail/Nichicon/RL80J102MDN1KX/?qs=sGAEpiMZZMukHu%252bjC5l7YWudW%2f5gEhSlO9%252b3hwaSSsM%3d

author: wraper
author_rank: Unknown
timestamp: October 11, 2017, 08:23:16 pm
content: Quote from: Old Don on October 11, 2017, 08:11:47 pmPolymer cap is not drop in replacement for electrolytic cap and may cause issues. Also it is more expensive. Also if used as replacement, capacitance should be reduced by around 2-3 times.
TENMA 72-10505 Current limit problem - Page 1
Forum section: electronics / repair

author: brumbarchris
author_rank: Regular Contributor
timestamp: October 10, 2017, 07:51:18 pm
content: Hi all,Just started to actually used my recently purchased TENMA 7210505 power supply and it turns out it is having a current limit problem on channel 1.If I set the current limit to anything lower than 87mA, the channel goes into Constant Current mode as soon as I enable it (without external load), although it displays "0" for the drawn current. Once I gradually increase the current limit, the channel goes out of that state and manages to eventually ramp up the voltage to whatever value it is being set to.For the moment, I am not sure if this is a bug or "feature"; I plan to open it up over the weekend, but until then I would be interested in knowing if anybody else had a similar problem, if it is a fairly common thing for these "cheapies" and how you solved it if you faced that.Regards,Cristian

author: wraper
author_rank: Unknown
timestamp: October 10, 2017, 08:37:34 pm
content: If you set, say, 100mA, does it limit current correctly? Measure actual current.

author: brumbarchris
author_rank: Regular Contributor
timestamp: October 11, 2017, 05:40:59 am
content: If I set current limit at 100mA and turn the output ON without a load, the current consumption indicator shows 0. As I attach a VERY high load and start decreasing its resistance, the indicator correctly indicates the current drawn by the load, but starts to get in CC mode at about 23mA (which is exactly the difference between the 100mA setting and the 87mA I've mentioned in my previous post.Cristian

author: Zucca
author_rank: Unknown
timestamp: October 11, 2017, 07:50:19 am
content: Meay be there is an offset of 87mA? Can you calibrate the current limiting circuit? Any pots there?

author: wraper
author_rank: Unknown
timestamp: October 11, 2017, 08:26:22 am
content: Quote from: zucca on October 11, 2017, 07:50:19 amYep, I was thinking the same. There could be an offset in either current sensing or voltage generated by DAC, calibration done incorrectly? I don't think there are any pots, in any case should look for KORAD KA3003D-3S when doing research as Tenma is just a rebadge.

author: wraper
author_rank: Unknown
timestamp: October 11, 2017, 08:36:56 am
content: These PSUs have DACs made of discrete resistors, something wrong might happened there as well.

author: Armadillo
author_rank: Super Contributor
timestamp: October 11, 2017, 09:51:48 am
content: The LM1117, 3.3V power supply is taken as a reference. Firstly make sure the reference is correct then go through the power supply calibration procedure.Edit: Power off, press and hold M4 button then at the same time press the power on button to enter calibration mode. Read the instruction manual....
Do  you know how to clean these rotary switch - Instek GOS-620 [Solved] - Page 1
Forum section: electronics / repair

author: Armadillo
author_rank: Super Contributor
timestamp: October 11, 2017, 04:04:51 am
content: Do you know how to clean the contacts of these rotary switches from the Instek GOS-620?I am also thinking of de-soldering it out to pry the plastic seal, but the front pull knob [smaller one] cannot be pulled out.thanks

author: cdev
author_rank: Super Contributor
timestamp: October 11, 2017, 04:16:40 am
content: First i would email GW instek and ask them what they recommend..For rotary switches generally, I use a tiny bit of Craig (I may be wrong on the spelling) "Deoxit"-Just a tiny bit on the contacts and then work the switch and clean any excess off. It makes a dramatic improvement. Don't use too much. just the tiniest amount.

author: Armadillo
author_rank: Super Contributor
timestamp: October 11, 2017, 09:47:44 am
content: @cdev;thanks, done, manage to dismantle the board out and clean it.
Fluke 196C Smashed Screens ? - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: October 08, 2017, 02:11:37 am
content: Searching on eBay for Fluke 199C or 196C for parts/repair, I see many units with displays that look like they were smashed with hammer.Is there a reason for this?Something like cutting off the electrical cord of faulty device?Also, are displays available for these units?Thanks

author: joeqsmith
author_rank: Super Contributor
timestamp: October 08, 2017, 02:57:27 am
content: QuoteMaybe just not as rugged as the Marketing group made them out to be?

author: Assafl
author_rank: Frequent Contributor
timestamp: October 08, 2017, 10:55:43 am
content: Maybe they were hit with a hamster?

author: Rerouter
author_rank: Super Contributor
timestamp: October 08, 2017, 11:13:46 am
content: I would take a guess that it really isnt robust, the screen is directly exposed without anything to prevent a direct impact when mr tradie throws it in the tool bag.

author: carl_lab
author_rank: Frequent Contributor
timestamp: October 08, 2017, 11:51:48 am
content: Quote from: Johnny10 on October 08, 2017, 02:11:37 amScrapping method to spoil dumpster diver's party...Some company policies are forcing such rude methods.

author: Dachpappe
author_rank: Contributor
timestamp: October 08, 2017, 01:04:58 pm
content: Quote from: carl_lab on October 08, 2017, 11:51:48 amThat's just cruel and should be forbidden.

author: carl_lab
author_rank: Frequent Contributor
timestamp: October 08, 2017, 02:53:45 pm
content: Quote from: Dachpappe on October 08, 2017, 01:04:58 pmExactly!

author: wraper
author_rank: Unknown
timestamp: October 08, 2017, 03:08:32 pm
content: Quote from: carl_lab on October 08, 2017, 11:51:48 amAt my previous work there was implemented such policy, after Nokia f..d our company in the ass when scrapped phone was repaired under warranty again, LOL.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: October 08, 2017, 03:18:43 pm
content: Quote from: Johnny10 on October 08, 2017, 02:11:37 amThere are a couple of video on YouTube that show teardown and repair of the Fluke scopemeters.The first one:This is a color scopemeter.The second one by Dave has a monochrome display:Looking at these teardown videos you can get a good idea on what parts were hit when the unit was smacked with a hammer.The color display is probably khs057qv1cr-g01. This is the part number of the display found in the R&S FSH3 Spectrum analyzer.The problem is that the datasheet for khs057qv1cr-g01 shows a 16 pin connector, but I believe the scopemeter has 22 pin connector.The Service Manual, with schematics can be found here:https://elektrotanya.com/fluke_192b_196b-c_199b-c_scopemeter.pdf/download.htmlI have attached the datasheet for the khs057qv1cr-g01 LCD Module, but it doesn't match the schematic in the scopemeter manual.I think that these eBay would be a very tough to fix.Regards,Jay_Diddy_B
Hameg Spectrum Analyzer Power Supply -- Unidentifed Diode - Page 1
Forum section: electronics / repair

author: rodd
author_rank: Regular Contributor
timestamp: March 18, 2017, 10:28:27 pm
content: Hi folks,I started to repair a Hameg 5005 Spectrum Analyzer which has no trace on the screen.So I started with the power supply.Up to now, I fdiex the +12V replacing a TL082 op amp and a TL431 regulator.All low voltages are ok now, but I have a problem in the HV.When I start to follow the schematics I fund D1557 (smd type) marked with a *.I looked everywhere in the other sheets od the manual and there is no mention to it.Can anybody figure out which diode is it?It seems to be a zenner diode, so what voltage?Thank you in advance for the help.Roger

author: Dachpappe
author_rank: Contributor
timestamp: March 19, 2017, 08:35:15 am
content: Well I also didn't find anything where the exact value of the diode is mentioned.But by how the diode is placed in the circuit it should be a low zener-value.It's parallel to the Base-Emitter section of T1553 which according to the datasheet has a max voltage of 5 volts. So it's probably between 0,7 - 5,0V. Have you checked the zener if it's really dead?

author: bktemp
author_rank: Super Contributor
timestamp: March 19, 2017, 09:08:43 am
content: A zener diode actially doen't make sense, because it is in parallel with the base-emitter diode, therefore the voltage never goes higher than ~0.7V. In reverse direction it acts as a normal diode limiting the reverse voltage.I have a similiar power supply (PS5011) here, the diode is unpopulated. Maybe that's why the manual doesn't mention a part number.If you want to place a diode, a 1N4148 should do the job.

author: barroweer
author_rank: Newbie
timestamp: October 07, 2017, 10:55:45 am
content: Hello. I have such appliance (may be Hameg 5510) which i was got like a gift recently but almost completely broken down. Fortunately it has a few boards nearly intact, the power supply among them. I've made some photos of rear and attach link on the service manual of proper quality (http://www.frankshospitalworkshop.com/equipment/documents/workshop_equipment/manuals/Hameg%20HM5010-5011%20Spectrum%20Analyzer%20-%20Service%20manual.pdf). And, interestingly, on my board this diode wasn't placed at all (see pages 37 and 50 in service manual). Does your board have this one?
Heatsink Connector repair - Page 1
Forum section: electronics / repair

author: PotatoBox
author_rank: Regular Contributor
timestamp: October 07, 2017, 01:35:13 am
content: So, I was replacing the thermal paste on my Thinkpad T430 and I accidentally chipped off a part of the plastic part for the cable (I suppose the plastic became brittle because of constant heating), so some of the wires can now come out of the plastic, but they slide on the pins fine. I don't feel comfortable leaving my laptop like this (as the wire could slide off the pin and cause the fan to shut off), does anyone know what this port is called so that I can solder in a new connector.

author: Armadillo
author_rank: Super Contributor
timestamp: October 07, 2017, 03:42:18 am
content: http://www.ebay.com/itm/20-XH2-54-5P-Connector-Kits-2-54mm-Pin-Header-20-5P-Housing-100-Terminal-/252489098689?hash=item3ac985e5c1:g:CKEAAOSwimdXpF0RIts not by soldering. Its by crimping. So you should have a crimping plier. Proper plier is not cheap. Otherwise improper one, the wire will easily come loose.Might as well buy short piece of cabled connector, cut and solder the wires and tape.http://www.ebay.com/itm/XH2-54mm-10cm-Wire-Cable-Double-Connector-2P-3P-4P-5P-6P-7P-8P-10P-/272299280234?var=&hash=item3f664d476a:m:mx2RZn8BUAicePwkkmyftVw

author: Gyro
author_rank: Super Contributor
timestamp: October 07, 2017, 09:43:59 am
content: You might just be better just securing the wires in situ once plugged in. Maybe a fine cable tie which stops the loose wires sliding against the still secure ones. Maybe even a thick adhesive (caulk, nail varnish?) that won't wick down into the connector contacts.Edit: Alternatively, just get a new plastic connector housing, you can clip the existing crimped contacts into that with no need to re-terminate anything (they enter from the back as you have found).

author: voltz
author_rank: Frequent Contributor
timestamp: October 07, 2017, 10:05:33 am
content: Yes, find a connector with attached cable from somewhere (ebay or junk box). Chop off your old connector and re-solder the new connector in place. Keep the overall cable length the same as it is now otherwise it may not fit back into the laptop. Insulate the wire joints with thin silicon rubber sleeving. May be worth staggering the position of the cuts in the wires to stop it bunching in one big group.Another way would be push the pins back in the plug as far as they go, then apply a small amount of hot glue at the back to hold them in. Not very nice but it would work at a pinch.A proper fix would involve buying a new fan/heatink assembly, or buying a crimp tool and changing the plug, but then the wires may be too short depending on how tight the fit is to the laptop socket.Hope that helps.
reattach lifted traces with Loctite Red? - Page 1
Forum section: electronics / repair

author: Old Don
author_rank: Regular Contributor
timestamp: October 05, 2017, 12:38:41 pm
content: I got thinking about what product to use on lifted traces or solder pads that one often finds on previously repaired boards. Not missing traces, but ones still there, but up in the air. One of the problems is the need to solder replacement components to the repaired copper pads after doing the trace repair. That takes heat which kills a bunch of cements or glues, but Loctite Red after curing is rated to 500 deg's F (260 deg's C) and I've used it in the past to glue together not heavily stressed broken metal parts where epoxy has failed. So I was wondering if you use a low temp solder if it might be possible to not lift the repaired traces a 2nd time and therefore end up with a decent result.Has anyone tried this or some other high temp product? I'm going to try this on the next board in need of TLC that I find. Thoughts?

author: sprintcarfan
author_rank: Contributor
timestamp: October 05, 2017, 03:59:32 pm
content: Loctite Red (272) is anaerobic, so it might not ever cure properly on a thin trace?

author: joeqsmith
author_rank: Super Contributor
timestamp: October 05, 2017, 04:34:40 pm
content: I use Loctite Tak Pak for traces and Black Max for bonding wires. If things are really unstable, I have resorted to epoxy.

author: keymaster
author_rank: Regular Contributor
timestamp: October 05, 2017, 07:26:35 pm
content: CW2500 from Chemtronics . it can withstand temperatures from -48 to 315 °C for a few seconds . it is for coating but it does what you want just fine .

author: stmdude
author_rank: Frequent Contributor
timestamp: October 05, 2017, 08:43:08 pm
content: Here's a video of a guy that really pays attention to the details when it comes to repairing lifted pads (and traces)

author: KL27x
author_rank: Super Contributor
timestamp: October 05, 2017, 09:23:36 pm
content: QuoteI bet joeqsmith pays attention to details, too. Bonding wires? Seriously!?

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 05, 2017, 11:00:33 pm
content: Quote from: KL27x on October 05, 2017, 09:23:36 pmLouis Rossmann uses bonding wires.Plus it's kinda hard to glue a trace if itdoesn't exist anymore.

author: The Guy
author_rank: Regular Contributor
timestamp: October 05, 2017, 11:18:03 pm
content: Use whatever the dentists use for gluing metal stuff to our teeth... I'm sure it's the best product in the universe.

author: Old Don
author_rank: Regular Contributor
timestamp: October 07, 2017, 01:18:41 am
content: Quote from: The Guy on October 05, 2017, 11:18:03 pmI'm sure it is strong and it cures with UV light, but I don't think teeth get heated to 250 deg's C and that's a problem with soldering repaired traces.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: October 07, 2017, 01:49:22 am
content: TB 43-0127 calls for epoxy for repair of delaminations and for setting of replacement eyelets
RCA Oscilliscope WO33A major damage - Page 1
Forum section: electronics / repair

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 07, 2017, 12:46:52 am
content: I got this and its a work of art from the 60s, except its cracked in 2. Its been dropped hard enough that the inertia of the mains transformer bent the back plate, and allowed trans. to hit the main bakelite type PCB and crack it right in 1/2 in a line across the middle. Also broke the leads off 2 1W resistors, and in another place and another crack that cracked 2 traces.The traces on this PCB are of the tinned with solder type, and EVERY single trace that needs repair, its just a bunch of perfect pararllel lines, so thats easy.The front panel has bent bent too. Hard enough to move the CRT back, bent the back plate aswell? Or was it all at the same time? The CRT is not connected to the front panel, so the backplate moving back, would pull the CRT back, but not the front panel into the case . A vac tube next to the CRT, at the front bell end, had all its 7 HEAVY pins bent to the side.....by the CRT hitting the glass of the tube, all that glass is STRONG. The socket looks fine tho.The CRT bakelite connector is cracked, but the wires/pins are fine.The CRT has a few little bits of white cermaic looking stuff, rolling around in it. I hope its not from somewhere critical inside it. CRTs can be built like akeen to Swiss watches (according to great old fashioned Tektronix video on making CRTs)Other than that I bet it works, if the switches/caps/tubes do. Looks pretty clean inside.Every trace and joint on that board needs checking though.I have it mostly apart, so I can fix the chassis/plates/etc. Then just to glue the PCB and bridge 14+2 traces.this vid is not me,i should up load a few pic's of mine at a later time
Name of an obscure connector - Page 1
Forum section: electronics / repair

author: Kolby_G
author_rank: Newbie
timestamp: October 05, 2017, 09:55:39 pm
content: Hey all,I am looking for the name of this cable or connector, it's from a Unifi G3 Dome Camera. Unfortunately the camera fell off the wall and the cable was damaged. I would like to repair it if possible since all that was damaged was the cable. Does anyone have a clue as to what this connector is called? I can't find anything close on DigiKey or Google, mind you I have no idea what I am looking for.Thanks

author: John_K
author_rank: Newbie
timestamp: October 06, 2017, 01:00:50 am
content: Can you post a photo of the end of the male end and a photo of the female connector where it plugs into?

author: sixstringartist
author_rank: Newbie
timestamp: October 06, 2017, 01:39:14 am
content: Looks similar to FPC but something seems a bit off.

author: Kolby_G
author_rank: Newbie
timestamp: October 06, 2017, 09:53:44 pm
content: I have looked at LVDS connectors, but can't find anything that looks like this one. Here are a couple more pics as requested. The female connector is in my first pic, I cant really get a better one. The connector just pushes in, no latches or anything.
vtech cs6129-31 repair part identification - Page 1
Forum section: electronics / repair

author: tassadarforaiur
author_rank: Newbie
timestamp: October 05, 2017, 07:34:32 pm
content: I'm trying to fix my 2nd handset for a pair of wireless phones, the working phone has a blue stripe on the highlighted part (diode?) d6, while the non-working phone has a more charred look. otherwise both pcb's look the same under a magnifying lamp. can anyone advise how to test/identify the part? my tool list consists of: soldering iron, desoldering iron, multimeter, and bench psu.Thanks for the help!

author: keymaster
author_rank: Regular Contributor
timestamp: October 06, 2017, 01:56:09 pm
content: The component seems to be a diode, what kind is difficult to say. You will need to desolder the one with the markings, to identify the diode. The 2 diodes seems different but are the same from another manufacturer .Test them with the multimeter , in diode mode . The blue stripe is the cathode.
Need Help idenfiying A Part: XPS 18 No power fault - Page 1
Forum section: electronics / repair

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: October 05, 2017, 08:25:30 pm
content: Hello everyone. I've recently obtained an XPS 18 tablet that didn't power on. It tried, but it would instantly shut off. Removing the HDD made it at least spin the fan for half a second. Anyway, I've discovered the fault, and its one of two diodes on what appear to be part of the power input/switching circuitry.Its the rightmost black square, one side looked a little iffy.I bypassed it with a very messy soldering job, and the damn machine actually POSTs, so I'm almost certain its the fault.Now I need to figure out what the heck it is. It must be a diode of some sort, all four pins on each side are commoned together, and in one direction, read a voltage drop of 0.200v and in the other, infinite.The part reads 1317 with a sideways SIF to the left of it.I'd love to get this machine working properly, so if you guys could help me find a replacement part, that would be awesome.

author: iamdarkyoshi
author_rank: Frequent Contributor
timestamp: October 06, 2017, 02:03:47 am
content: Good news and bad news. Good news is that I just ran some bodgewires to a 30v 15A schottkey diode that was too large to surface mount, and it boots fine. However, it rejects all chargers, even though the sense line is not broken anywhere along the line, my dell laptop has no issue with my chargers.It also rejects the battery, saying the temperature is too high, which is weird, and I have a spare battery, it behaves the same.
SMPS output resistors  - Page 1
Forum section: electronics / repair

author: FujiLim
author_rank: Newbie
timestamp: October 05, 2017, 03:09:39 pm
content: Do not know where exactly to ask this question, guess I would ask it here.Having repaired few PC SMPS, most common problem were the bad output caps.I have noticed most of the supplies have resistor or resistors(usually 3W resistor) very close to output caps and those caps due to the excessive heat fail quite fast.These reasons for this that come to my mind:SMPS stability if for some reason there is no load and PSU is turned onManufactures put them there so the PSU intentionally fail, like a time bombOr I am probably missing some stuff, I would like to get your input on this.

author: retrolefty
author_rank: Super Contributor
timestamp: October 05, 2017, 05:11:00 pm
content: I suspect it's a minimum load requirement for the regulation chip/circuit. But Iwill follow this thread.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 05, 2017, 05:20:23 pm
content: Yes, minimum load. Usually the underlying problem is compensation, where the output cannot be guaranteed no overshoot, over manufacturing and aging variances. During startup, or when a load is disconnected, the output voltage shoots up, and it'll just stay there if no load is present. It could also be that the controller oscillates in some way when lightly loaded. The load resistor bleeds away the excess voltage, and keeps the voltage closer to nominal.Tim
Old Function Generator - Page 1
Forum section: electronics / repair

author: tuxitheone
author_rank: Newbie
timestamp: August 20, 2015, 06:53:21 pm
content: Hi!!!i hope ther is some one ther can help...i´m in need of the Service Manual for:Bremi BRI-8510 Function GeneratorSo if some one knows ware I can get it PLZ help...Thomas

author: svh
author_rank: Newbie
timestamp: October 05, 2017, 03:47:50 pm
content: Hello, i have the same problem as you, i need a service manual (schematic) ofthe function generator BRI 8510. So i can try to repair it. Maybe you can help me.many thanks, Serge
Metex ME-31 repair possible? - Page 1
Forum section: electronics / repair

author: Zermalmer
author_rank: Regular Contributor
timestamp: October 04, 2017, 08:04:42 pm
content: Hi,my brother bring along a Metex ME-31.He told me it is broken and "maybe get wrong voltage"It is measuring voltage in 400mV range and doesn't switch ranges up.Due to the fact the display nearly display all display symbols it is naturally unusable. (that it displays 1234 is coincidence)Doesn't tested V~ and Ohms, but I think the behaviour is the same.If I switch over to diode testing it goes to sonstantly beep and going for amps it doesn't change anything.I checked fuses, display contacts and for optical damages....All perfect and in very clean condition... also no bubbles or smell somewhere inside.I even checked rotary switch, but this also is nearly new... not even one scratch on the surfaces...Looks like he blown this baby away shortly after buying it or rarely used it and blow it after guarantee.Any idea for a check to save it, or is the time wasted to investigate in this "baked" device? (e.g. main chip killed by user)thanks and best regardsAndreas
LG W2240 vertical line - Page 1
Forum section: electronics / repair

author: nighthunter
author_rank: Newbie
timestamp: October 04, 2017, 06:13:00 am
content: Hi everybody,i want to ask if somebody can tell me what causes a cyan vertical line on this LG W2240 screen. Could it be in T-CON or a defective panel? I use this monitor as an extension for my microscope so the line is not a big issue, but if it can be fixed it would be better. I discovered that on full white color the line dissapears. (I am dealing with this kind of problem for the first time. My personal guess it that this is an internal break in panel. Am i right?) Photo of it is in attachment.

author: keymaster
author_rank: Regular Contributor
timestamp: October 04, 2017, 12:03:27 pm
content: the most likely suspect is the flat flex ,that connects the glass of the screen with the electronics . you can press the flat flex to the board while is working and see if the line disappears .
Troubleshooting TV PSU (help needed) - Page 1
Forum section: electronics / repair

author: victor
author_rank: Regular Contributor
timestamp: October 03, 2017, 10:38:58 pm
content: I have a 21" AOC TV that is not turning on, the standby led (orange) is ON but when trying to turn it on, the led goes on blue for a second and it shuts off and goes back to stand by (orange).There's a whine noise coming from the transformer.I couldn't notice anything obvious in the visual inspection, while I know it is probably something wrong with the power supply, I don't know where to start.I don't have schematics, but the circuit is fairly simple as it is a single sided board. I included the best pictures I could take of the top and bottom, and a combined top/bottom image.From the quite loud noise coming from the transformer I suspect that it is not switching as fast as it should be, due to some dry cap, but it is just a guess.Any suggestion of where should I start?

author: victor
author_rank: Regular Contributor
timestamp: October 03, 2017, 10:41:54 pm
content: Combined top/bottom picture

author: DrGeoff
author_rank: Frequent Contributor
timestamp: October 03, 2017, 10:52:43 pm
content: The PSU could be shutting down due to a fault elsewhere.What are the PSU rails? Can the PSU be powered without the external loads connected to check the rails?Edit:OK, I see from the SS overlay that you have a 16V and 5.2V rail to test.And a few LED backlight rails.

author: retiredcaps
author_rank: Super Contributor
timestamp: October 03, 2017, 10:56:43 pm
content: You don't state what model, but some of the LED TV exhibit behaviour similar to what you describe because one or more of the LEDs have actually failed.Tons of info athttps://www.badcaps.net/forum/forumdisplay.php?f=31
One Winding in Brushless Servo is 2 Ohms Higher - Page 1
Forum section: electronics / repair

author: 691175002
author_rank: Regular Contributor
timestamp: October 03, 2017, 05:45:06 pm
content: I have a brushless servo that appears fully functional but has a slight torque/speed ripple that produces waves in its final application.The datasheet says the windings should have 4.2r of resistance, and A to C measures correctly. AB and BC both measure 6r. A working servo measures 4.2r across all windings as expected.I know that typically windings fail fully open or show decreased resistance as the insulation degrades. Any idea what could have happened here?Unfortunately I have no idea what the electrical schematic of the motor looks like. Maybe they split each winding into three parallel magnet wires and one got loose?

author: floobydust
author_rank: Super Contributor
timestamp: October 03, 2017, 09:15:09 pm
content: I'm not sure if it's wye or delta winding.I'd take it apart as extra ~2R is huge and would heat up and melt things, if it's a bad connection.Perhaps the factory took a lunch break after winding one correctly.

author: 691175002
author_rank: Regular Contributor
timestamp: October 05, 2017, 02:20:08 am
content: For reference I took the servo apart and it is wired as a wye with two parallel windings per leg. One of the six total windings is open and as there is no visible damage, so it looks like the only way to save the servo would be to rewind it.

author: floobydust
author_rank: Super Contributor
timestamp: October 05, 2017, 06:13:52 am
content: maybe resolder the tie point, sometimes varnish is still there. I usually see windings open-circuit at the connection points, never in the middle unless cut/chafing.
Sharp Aquos LC70LE747E Grey transparent lines  - Page 1
Forum section: electronics / repair

author: GarryDD
author_rank: Newbie
timestamp: October 02, 2017, 06:17:14 am
content: Hi everybody,Could someone help me with my tv ?Its a Sharp Aquos LC70LE747E.The problem: from Time to Time appear horizontal Grey transparent lines from left to right. About 16 lines at all. They Disappear After tv restart, most of the time. Very seldom a longer cool down is needed to make them disappear.Apart this Problem the tv works Great.Tv is already open. Electronics Look good to me. Can provide pix.Any idea how to Track down the cause of the Problems?

author: Armadillo
author_rank: Super Contributor
timestamp: October 02, 2017, 06:27:40 am
content: Try simple thing first;

author: GarryDD
author_rank: Newbie
timestamp: October 02, 2017, 09:55:00 am
content: Thanks; gonna try this today although i Think the reason is somewhere Else. Because the Problem seems to disappear after a cool down. My Stripes Look different too.

author: Armadillo
author_rank: Super Contributor
timestamp: October 02, 2017, 11:01:13 am
content: Quote from: GarryDD on October 02, 2017, 09:55:00 amWell, you better hope that it is because beyond that it's much more difficult and will need a expert to dismantle to the LCD itself to put a supporting pressing pad. Cross your fingers.Maybe you wait for a while to see if others have a differing view.

author: GarryDD
author_rank: Newbie
timestamp: October 02, 2017, 11:15:07 am
content: The Panel should be ok, was changed 1 Year ago while still in warranty.Tv is already open, the Caps and Everything Look good.

author: wraper
author_rank: Unknown
timestamp: October 02, 2017, 05:43:38 pm
content: Quote from: GarryDD on October 02, 2017, 11:15:07 amHow it makes any difference? Sounds exactly like problem with LCD panel.

author: GarryDD
author_rank: Newbie
timestamp: October 03, 2017, 08:46:48 am
content: Any other suggestions ?

author: Rasz
author_rank: Super Contributor
timestamp: October 03, 2017, 01:04:24 pm
content: Gate Drivers are failing, they are either on external flex(=might be connection failing, can be sometimes bodged by putting pressure), or directly on glass (directly to recycle bin)