hybridfree/eevblog-posts huggingface dataset:
Impossible to clean solder mess -microsoldering 0201 - Page 1
Forum section: electronics / repair

author: GregRS
author_rank: Newbie
timestamp: February 10, 2019, 05:27:27 pm
content: Hello,I want to ask if someone could help me with my big mistake cleaning/resoldering 0201 filter on my board..My mistake was: Taking Sn 0,3Ag 0,7Cu 2%Flux solder wire at the place of my standard 60/40 or 63/37 solder wire with the same little diameter.I have a terrible mess around my element pads etc.. and I tried to clean it with solder wick (2 types) of course with flux, but this thing won't stick and get off of my boards.It melts very slow with 420-450°C and go back(hard) immediatly (2 times faster than standard tin)I tried to add a little bit of standard 60/40 solder to easier suck it with solder wick, but this thing still won't get out... I can melt it and move a little on sides etc but I have absolutly not idea how to get it out from my board. (Remember it's 0201 element so I have to be carreful with other parts next to it.I have 2 different quite good irons with smaller and bigger tips and AmScope SE400-Z microscope so I think, I have enough of basic hardware to do it, but absolutly no more ideas for that bad situation.PS: I'm amator still learning and I don't have hot air station.Sorry for very bad quality of photo - taken with temporary old smarphone, in real it's mutch better and clean view.I will appreciate a lot any kind of help!Thank you and have a nice day!

author: SilverSolder
author_rank: Super Contributor
timestamp: February 11, 2019, 02:12:34 am
content: Take your solder braid, add a little flux to it, and use your iron to wet it with a very tiny amount of 60/40 solder. Use this prepared strip as a "floor mop" under your soldering iron to wipe the unwanted solder away from the board.400 degrees sounds very hot and that definitely risks damaging the board. 350 degrees or even less should be enough - try to figure out the lowest temperature that it will reliably melt at (by experimenting with the 'bad' solder away from the board). The idea is to use "enough" heat, and not more than that.It is a good idea to practice all this on a piece of scrap board before attacking the important project.

author: TimCambridge
author_rank: Regular Contributor
timestamp: February 11, 2019, 02:42:07 am
content: And cut off a few cm of braid so that you're not using the whole reel as a heat sink

author: GregRS
author_rank: Newbie
timestamp: February 11, 2019, 10:23:05 pm
content: Thank you VERY much for your responses and ideas for my problem,first I will take some old board to recreate the same mess on bigger surface to test mixing that "very bad" solder with normal 60/40to reduce melting point on my "1st, main and important" board.I think that idea with test on the other board is a great idea.Thank you very much again andhave a great day/evening (depend of your time zone)
ATTEN ADS2202CA - Page 1
Forum section: electronics / repair

author: softm
author_rank: Newbie
timestamp: February 11, 2019, 11:28:16 am
content: Was using this oscilloscope atten ads 2202 ca very rarely (using hand-carried verison of JDS)Few days ago it stop working.Was need change shorted capacitor 1000uF/16v in its PSU.After this i replace all other capacitors in PSU, cause all stop works after warming up in few minutes.And i made racalibration. Seems this was a mistake.Now oscilloscope shows something strange - signal is everywhere.Can anybody help with firmware, maybe this helps ... of suggest how to act in this situation ...
DMM cemetery .. #1 Appa 106 , Cyrustek cyrustek es51962 - Page 1
Forum section: electronics / repair

author: Giorg
author_rank: Contributor
timestamp: February 18, 2019, 09:10:36 am
content: I've received this little fella but V range shows OL all the time. Diode and temperature are not working properly.I've checked all the input components, sparks gaps are open, PTC are around 1.5k and resistors are fine.I was not able to find a proper schematic. I've learned that this is a common design in other rebranded meter.I've lifted pin 35 VR1 "measurement input" and it's at around 1.2V all the time. So I reckon the IC is fried and needs to be replaced, but I cannot find any for sale. It's a Cyrustek ES51962http://www.cyrustek.com.tw/spec/ES51962.pdfhas anyone found a source for this old IC?Another option will be to salvage the part from like a unit T70B, but I was not able to find a broken one for spares!

author: Mkdsime
author_rank: Contributor
timestamp: February 18, 2019, 06:42:57 pm
content: maybe try simple thing as cleaning the contacts ?

author: coromonadalix
author_rank: Super Contributor
timestamp: February 19, 2019, 12:31:23 am
content: I dont think you'll be able to order it alone ??The same chipset is used in Uni-T UT70B or in the xtech EX730 clamp-meters

author: mzacharias
author_rank: Frequent Contributor
timestamp: February 19, 2019, 12:47:27 am
content: Take another digital multimeter and measure the input resistance (impedance) at the volt-ohms jacks in DC volts mode.10-11 Meg-Ohms is typical.
MOVED: MOVED: Flyback secondary output manipulation - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: February 10, 2019, 11:20:56 pm
content: This topic has been moved to Begginers.I am moving it because I fell like I have way to many basic questions about it and the repair section may not be the best one.https://www.eevblog.com/forum/beginners/understanding-a-flyback-circuit-pwm-controller/
HP6632B Repair, fixes errors # 1, 2, 3, 4, 5, 80, 11 - Page 1
Forum section: electronics / repair

author: poppniete
author_rank: Contributor
timestamp: February 10, 2019, 01:59:57 pm
content: Hi folks!I just fixed my HP6632B power supply. The symptoms where the following:- no output- "Prot", "Err", "Dis" indicator lit- OT and OV indicated- Errors 1, 2, 3, 4, 5, 80, 11 presentIt all boils down to blown fuses F300 and F301 which protect the +/-15 V and 5 V bias supplies. I know, this is nothing spectacular, but I'm writing you this because the troubleshooting flowcharts in the manual do not treat this special mode of failure and the error numbers lead you nowhere.I hope to spare you some time chasing the red herring.Regards,Jan
MVME 162-212 repair - Page 1
Forum section: electronics / repair

author: SoundLockEng
author_rank: Contributor
timestamp: February 08, 2019, 08:58:39 pm
content: Hi all,I am working reassembling an old mixing console (myspecialty) with an automation system (not my specialty) that uses an MVME 162-212 card. This is out of my area of knowledge so I posting for anyone that has experience with these modules as I’m aware they were widely used in industry.as far as I can see the MVME is used as the interface for the device to communicate via Ethernet with a computer via a LE2006a to 10base2T network.There is also an Omnibyte OB68K/VME1 in the unit.I can ping the network and other devices appear but the MVME based device does not. (The Ethernet Adapter works tested on another working device) I see the adapter receive the ping but to respond like the others do.The MVME has four indicator led’s and a photo is attached.Fail is illuminated and fuse is not.All fuses are fine.Any pointers as to what to look for would br greatly appreciated!I have looked at manuals but the data is a bit ambiguous to be to how these LEDs are activated.All the bestChris

author: SoundLockEng
author_rank: Contributor
timestamp: February 10, 2019, 12:31:43 pm
content: By way of an update, yesterday I was able to get a serial connection into the accompanying Mac G4 and use ZTerm to receive data from the 162. It appears on reset the 162 spits out gibberish rather than the usual ‘make, model, serial revision data’ that you would expect to see from port 0.
Burned out my DSP1550 RuiDeng power supply - Page 1
Forum section: electronics / repair

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2019, 02:42:02 am
content: I was testing an ESC and brushless motor at about 10 amps, power cut off, the screen went white to black.One of the fets under the fan leaked a couple small solder balls through the vias and it smells burned.Is it likely there is more damage? I'd expect the screen and micro to still function. I checked the fuses.

author: metrologist
author_rank: Super Contributor
timestamp: February 11, 2019, 03:29:23 pm
content: I know Dave did a video but I think his failure was a little different.Anyway, I ordered another one so at least I can compare the two when I get to troubleshooting.I'm also going to look for a real bench supply - there is a no frills single channel keysight on craigslist for $180, seems like a good deal.
Rohde & Schwarz SMU200A Vector Signal Generator repair log - Page 1
Forum section: electronics / repair

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: January 29, 2019, 05:36:15 pm
content: Today i recieved a broken SMU200A. It is the 3 GHz single channel version.The description was "firmware problems".After powering up Windows is throwing different errors at the boot process.I did a BIOS reset but that didn't worked. I decided to replace the dead CMOS battery. After another BIOS reset and a properly adjusted date & time its booting up properly.The signal generator application threw some errors that disappeared after a self-adjustment.Unfortunately the keys and the rotary encoder aren't working at all. Just the power button and the LEDs are working.The instrument can be operated with a USB mouse. External keyboards don't work either.It seems to be a windows problem. Anybody has experience with these kind of problems?Things done:cmos batterydust cleaninghdd copyself-adjustmentTo do:bring the keyboard back to workmore dust cleaningfan replacementhdd->CF-Card replacement?CCFL->LED replacement?

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: January 31, 2019, 11:17:24 am
content: It works!I booted the device into the recovery and did a full system rollback.After that I installed service pack 3, this system update (https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_firmware/zip_1/SystemUpdate4SignalGenerators.zip)and then the latest firmware (https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_firmware/exe_1/SMU200A_32028621.exe).I didn't expect this repair to be that easy especially for the price i paid for this item.The next thing is a fan replacement. The ones that are built in are very noisy.

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: February 08, 2019, 10:44:36 pm
content: Today i replaced the hdd with an ssd.I used one of these adapters:https://www.aliexpress.com/item/44-Pin-M-2-NGFF-SATA-SSD-to-2-5-IDE-SATA-SSD-Converter-SATA-Adapter/32798017224.html?In total it is cheaper than buying an IDE ssd.I also did a boot time comparison.hdd: 2:56ssd: 1:58The slowest part is the initializing of the firmware. That isn't any faster with that ssd.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 09, 2019, 12:25:09 am
content: Nice project! - What does a vector signal generator actually do? - I can understand a vector signal analyzer, but a generator sounds interesting.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 09, 2019, 12:34:55 am
content: have you made backup or image copy of the original installation? thats the first thing you should do... congratulation on your success.

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: February 09, 2019, 10:56:19 am
content: A vector signal generator is able to transmit complex signals. You can manipulate the magnitude and the phase angle.This unit even has two baseband generators. But im not sure why i need two of them@MechatrommerThe hdd backup was the first thing i did.
Panasonic Schematic for TC-P42ST30 Plasma TV - Page 1
Forum section: electronics / repair

author: N9ZN-Extra
author_rank: Newbie
timestamp: February 09, 2019, 05:11:59 am
content: I need to locate a readable schematic for my Panasonic TC-P42ST30 Plasma HDTV. Does anyone have one or can anyone refer me to someplace that has readable schematics for this TV?The background is several schematics have been ordered only to discover that the drawings are blurred when enlarged to a readable size. I am not over enlarging, the PDF files I have purchased so far are unreadable, part numbers and voltages Etc are unreadable.

author: lekso
author_rank: Newbie
timestamp: February 09, 2019, 09:42:40 am
content: https://elektrotanya.com/showresult?what=Panasonic%20TC-P42ST30&kategoria=&kat2=all
Ordering spare parts from Aim TTI / Thurlby Thandar? - Page 1
Forum section: electronics / repair

author: salvagedcircuitry
author_rank: Regular Contributor
timestamp: February 08, 2019, 02:14:15 am
content: Has anyone ordered repair parts from Aim-TTi (thurlby thandar Instruments)?How long did it take and did they ship to the USA?I'm looking for some replacement threaded terminals for my CPX400a, and they still sell a variant of the power supply that uses the same repair part. It's only been 3 days or so, but I am wondering if anyone has been successful in buying parts from them.Thanks!

author: bd139
author_rank: Super Contributor
timestamp: February 08, 2019, 12:50:17 pm
content: Yes have bought quite a few things. Takes 5-7 days here in UK usually. Just call them up and ask. Prices are really cheap. Think there is a minimum order of £5 though.
AGILENT U1233 issue - Page 1
Forum section: electronics / repair

author: maker
author_rank: Newbie
timestamp: January 29, 2019, 01:39:01 am
content: helloi have issue with this multimeter,i bought it from ebay..it should give numbers when it get switched on however you only see slashesas you will see in the video, any help would be great

author: Simon
author_rank: Unknown
timestamp: February 07, 2019, 07:27:27 am
content: Welcome to the forum, please do not post the same topic twice as it causes confusion.
DDS function generator MOTECH FG503 - Page 1
Forum section: electronics / repair

author: RayeR
author_rank: Contributor
timestamp: February 08, 2019, 11:51:10 am
content: Hi,I have repaired one old function generator MOTECH FG503. I dumped all programmable ICs and explored program memory. From what I've seen I come to conclusion that this device have some calibration menu or protocol, probably via RS232 or LCD. But I don't know how to access it as I don't have any documentation and software. It is impossible to find any resources than brief specification of this device - please do have anybody something more?Anyway I was able to find some calibration values in EEPROM and created partial data map. It may interest other users of this device. I wrote an article, it's CZ lang only - you can use google translato:http://rayer.g6.cz/elektro/fg503.htmThe EEPROM map table has description in english.
SOT 8pin pwm ic - Page 1
Forum section: electronics / repair

author: najrao
author_rank: Regular Contributor
timestamp: February 04, 2019, 05:32:13 am
content: Long shot, but anybody recognise this code: 80YL5E5EU? Used in a Oreva 30W LED lamp ballast. Pinout is unlike 384x, in that output is at 5, Vcc at 6. There seem to be no external cap for setting frequency. The power mosfet receives NO drive, but the ic has only uA of start-up current, and picks up 2.06mA at 15.6V, which holds down to 7.8V. Pin 1 goes active after start-up, and holds a reference(?) voltage of 2.673V. No pin shows any pulse activity, but possible some shutdown is active. Google and data search engines return nothing.Thanks for any link.

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 07, 2019, 01:20:02 am
content: Should be this:https://e-neon.ru/catalog_files/pdf2/sd6800%20datasheet_1.3.pdfSorry, couldn't find a link to datasheet on manufacturer's website, it does look like they may send (free?) samples though.

author: najrao
author_rank: Regular Contributor
timestamp: February 07, 2019, 02:34:21 am
content: Thank you, sir. The pinout and measurable parameters fit exactly.I have discovered the problem: a separate 431 based mains overvoltage circuit was erratic, and now taken out altogether. The driver works perfectly without.A nicely made 30W LED lamp got a new lease of life!
Heathkit IM-2419 Freq Counter - Page 1
Forum section: electronics / repair

author: K3ors
author_rank: Newbie
timestamp: February 06, 2019, 10:50:15 pm
content: Counter has been unused for years so I replaced Electrolytic Caps. Also did Easter Egging and replaced U!, U2, and U3. Have finally got it to show the correct frequency at 146.52 after adjusting C27.Display shows 0000 both ranges and clock rate with antenna disconnected. With antenna connected the display varies radically. When I key my transmitter in any of the HF ranges or clocks the display changes but is still erratic. The 20 to 225 only correctly displays the VHF frequency. I have12.07 on Pin 8 of U10. Visual looks fine.I built the kit and it worked fine until it was stored for a number of years. Ideas???

author: Psi
author_rank: Super Contributor
timestamp: February 06, 2019, 11:09:19 pm
content: If age has killed it check all the caps.
X-tronic 4000 series solder station help needed - Page 1
Forum section: electronics / repair

author: cncjerry
author_rank: Unknown
timestamp: February 06, 2019, 04:29:37 am
content: My brother has the subject solder station, an X-tronic 4000 series. Along the way of normal use, the fan for the desolder hot air jammed or inhaled a piece of swarf. The results of the jammed fan were an overheated R18 (ha, magic smoke, burned to a crisp) and possibly a blown thyristor. As near as he can tell, my brother thought R18 was 820K but the fan, which we suspect is still good, only rotated at low rpm when fully turned up. He ordered the thyristor but needs the value of R18. He tried various values down to 2k with increasing rpm until the last resistor, a 2k, overheated as well.He emailed the company and was given the middle finger salute concomitant with a note about the schematic in whole and the part specifically being their valuable IP. I guess a simple thyristor based circuit controlling an A/C voltage fan is IP in good ol', don't break any laws, recognize the work of others, Asian Economic Community.So the value of r18 would be much appreciated even though you might have to do a little disassembly. And speaking for my brother and me, I can assure you the favor will be repaid.Thanks,Jerry

author: helius
author_rank: Super Contributor
timestamp: February 06, 2019, 06:17:12 am
content: X-tronic doesn't even make anything. They are exclusively a badge-engineering shop and the result is that they don't even possess what you asked for.The 4040-XTS is a rebadge of Gordak 952, the schematic follows.

author: cncjerry
author_rank: Unknown
timestamp: February 06, 2019, 07:58:36 pm
content: thanks! Very helpful. It was 820k, by the way.
Linak CB6 Hospital Bed Motor Controller Repair - Page 1
Forum section: electronics / repair

author: David_AVD
author_rank: Super Contributor
timestamp: February 05, 2019, 01:27:55 am
content: Does anyone have any information on (or experience with) Linak hospital bed motor controllers? I have a few CB6 units that I've been asked to take a look at.

author: Jim Narem
author_rank: Contributor
timestamp: February 05, 2019, 03:03:55 am
content: The CB6 control unit looks the same as the invacare unit. If it's not actuating, crack it open and listen to the relays. Invacare used crappy no-brand relays, which I replaced with digikey PB2031-ND.Symptom was that only some directions (retract/extend) worked. It's not a high-tech device, especially considering it's outragous price.

author: David_AVD
author_rank: Super Contributor
timestamp: February 05, 2019, 04:29:23 am
content: On these faulty units, none of the relays actuate. The LED on the board lights red (and the piezo beeps) with every button press.The handset unlocks (with a magnet), but maybe the controller is still seeing it as locked as it does the same thing when the handset is still locked.There's no obvious damage to the board or components, but it's hard to know exactly how it operates without a schematic.

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 05, 2019, 06:35:46 pm
content: Hi!Have you checked "Franks Hospital Workshop" site? There are service manuals and technical documents for many varieties of medical and hospital equipment you can download free without registration to browse thro'!Chris Williams

author: David_AVD
author_rank: Super Contributor
timestamp: February 05, 2019, 08:20:56 pm
content: No, I hadn't see that site before. Thanks.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 06, 2019, 03:47:32 pm
content: The motors are very likely simple brushed DC motors.Finding info on those is much easier than on some specialised equipment they are used in.

author: David_AVD
author_rank: Super Contributor
timestamp: February 06, 2019, 07:52:42 pm
content: The motors would indeed be a brushed DC type, but that's not the issue here. It's the motor controller box that is faulty.
Puzzling Fluke 85 problem - Page 1
Forum section: electronics / repair

author: LazyJack
author_rank: Frequent Contributor
timestamp: February 06, 2019, 09:40:06 am
content: I just got an old Fluke 85 (one that predates the CAT rating). It measures voltage all right, and resistance sort of, but with open inputs it is fluctuating around negative 200kohms. First it looked easy, I checked all the usual suspects, that is everything has been already bathed in IPA, no burn marks anywhere, rotary switch cleaned, checked the VDRs, the fusible resistor, the input protection circuit (RV1, RV2, Q1, Q2, Q6, CR7, CR8, even removed these) but the problem persists.So it is puzzling now, as I was suspecting one of these components to be failed after some overload, but apparently not.Any tips on what else I should be looking next?

author: ModemHead
author_rank: Frequent Contributor
timestamp: February 06, 2019, 03:49:10 pm
content: This seems very similar to a recent thread:https://www.eevblog.com/forum/repair/dmm-cemetery-fluke-appa-metex/It sounds like you've done some very good trouble-shooting already. If you haven't yet, I would recommend studying the service manual section that shows the "signal flow" for the different modes. You'll find that the ohms mode voltage sense leads to U4P93 (AP1). Something must be influencing this path in the negative direction. It should only be influenced by the test current source coming through the fusible resistor, and the unknown resistance on the input jacks.There are no deliberate connections to the analog power supply in the front end, so it is unlikely to be component failure. The vast majority of the time I have seen this, it is leakage from contamination. It isn't always on the PCB, I have found leakage between wafers of the rotary switch before, and it is a maddening adventure to locate it. Otherwise it will probably come from inside U4 itself, probably as a result of damage to the internal voltage clamps.Hope this rambling helps.

author: LazyJack
author_rank: Frequent Contributor
timestamp: February 06, 2019, 07:29:15 pm
content: Hey, ModemHead, I was hoping you would respondThanks for the info, the signal flow charts are vry useful indeed. Time to do some more investigation.
How to retrace circuit boards and pcbs. - Page 1
Forum section: electronics / repair

author: albert001
author_rank: Regular Contributor
timestamp: February 05, 2019, 04:07:23 pm
content: I'm looking for some more information and advice how to re-solder / re-trace circuit boards where lead free solder has microcracks due to age.The problem is with an VIC (vehicle information center) in an mid 90s vehicle, (comprised of two circuit boards). I'm told the solder used by the manufacture at the time was a lead free solder and that with age eventually developed microcracks causing problems with the VIC.There are people who have retraced the VIC boards to repair them and get them working again. I think some have used a strong magnifying glass to locate microcracks in the solder.I have a couple soldering irons. A Weller EC2002M soldering station with temperature control and readout and an older Ungar soldering iron with many tips and various tips with heating elements, up to 1000 deg. F.From what I understand prior to re-soldering your suppose to clean off any board coating around the area being resoldered . Both circuit boards have some kind of conformal coating.I've never performed this sort of work on a pcb / circuit board before so am mostly guessing how to do it.I'm thinking of starting by using knife tip trying to reflow some of the solder joint/connections.I'm just looking for advice and the best approach to repair the two VIC circuit boards.

author: David Hess
author_rank: Super Contributor
timestamp: February 06, 2019, 05:05:22 pm
content: I have manually solder reflowed boards a few times. After removing any conformal coating and cleaning the board, I use solder wick and flux to remove the old solder from half of the connections to each part at a time and then resolder using my favorite tin-lead solder.
Inductor identification without schematic - Page 1
Forum section: electronics / repair

author: BenKenobi
author_rank: Regular Contributor
timestamp: February 05, 2019, 10:42:45 pm
content: I have a Bowens 500DX flash head sitting on the bench, the control board has released the magic smoke.The company no longer exists and schematics are impossible to find. I need to replace a pair of inductors, I have next to no information on what size they are - or do I ?? - I can find no inductors of the value on the top of these.Anyone care to take a gander at the images and offer some clues - I'm a rank amateur in this game so I don't encounter these things that often. It is in a remote switchable circuit providing 5VDC to a control board in the flash unit, least I think it should be 5V based on the presence of PIC's and LM358N, MC7805C elsewhere- why inductors in + and - ??What insanity would cook inductors such that the copper ends up on the PCB - I see no evidence that there's been any kind of short in the DC side except the inductors - did the switch shorting kill the inductors or the other way around? but it's all cooked so nothing to confirm who failed what and I lack the experience many of you guys have, how do you know whether the numbers on the inductors are nano or micro henry's ? - there are no vendor markings at all. The PWM switch is toast - actually exploded - it is also obsolete.http://www.theplasticshed.co.uk/images/images500DX/TOP200YAI.pdfIf the images are too large just let me know and I'll shrink them

author: DaJMasta
author_rank: Super Contributor
timestamp: February 06, 2019, 01:23:32 am
content: If you can ID the manufacturer, the markings may be helpful, but much like a lot of other passives, the markings are pretty minimal and can't really tell you the full story at a glance. Do you have at least one functioning inductor that you can measure? Can you match wire diameter and number of turns and reuse the core?I don't actually see the images...

author: BenKenobi
author_rank: Regular Contributor
timestamp: February 06, 2019, 02:23:47 am
content: Wish I did have a good one, both inductors are toast, no vendor markings at all, thinking of getting some 10 millihenry - the large cap is 400V 10 microfarad, can't read the small one without pulling components.There's an MC7508C nearby (Fairchild) that looks like it has been replaced - although the solder below the PCB says yes, the solder on top says no but without the schematic I've no idea if this is even the appropriate component.If anyone here has a picture of a Bowens Esprit DX500 control board that would help confirm - or even a schematic / parts list (beer tokens available).
Repairing Electronic Unit for BD35 compressor - output mosfets blown - Page 1
Forum section: electronics / repair

author: station240
author_rank: Unknown
timestamp: January 06, 2017, 01:15:46 am
content: Attempting repair of a Secop Electronic Unit for BD35 compressor, company formerly known as Danfoss.Model 101N0500 for 12/24V BD35 compressorReplacement unit is $150 plus postageBoard drives the BLDC motor in the compressor, and has 3 output mosfets, two of which are blown.Surviving mosfet saysIRF P222J8DFAF7343It's a SOIC-8 packageCannot find any datasheet for this International Rectifier part.Not found anything yet on power draw, bar a data sheet that recommends the main battery switch be rated to 20A.Only advice I've found on this unit is to replace it with a 48V BLDC controller for ebike, which then needs 48V to run to compressor at the same speed.

author: strawberry
author_rank: Super Contributor
timestamp: January 06, 2017, 02:42:13 am
content: IRF7343

author: JohannP
author_rank: Contributor
timestamp: February 28, 2017, 08:40:27 pm
content: Do somebody perhaps have a circuit diagram of the Danfoss Secop 101N0500 unit.I do have about 10 units all with problems on the mains side of the switch mode psu. The 12/24V side hardly goes faulty.Best regards.Johann Prinsloo.

author: Jorrie
author_rank: Newbie
timestamp: February 05, 2019, 11:57:35 am
content: Hi JohannDid you come right with a cct diagram for the Danfoss Secop 101N0500 unit? I am also sitting with a fridge which seems like this unit is faulty. I am very rusty on electronics but I am willing to try to fix the unit in order to get my fridge going again.If you can assist I would really appreciate it. My mail add. is inus.jordaan@vodacom.co.zaRgdsInus
Alternative diode bridges - Page 1
Forum section: electronics / repair

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 04, 2019, 10:03:05 pm
content: I have a blown PW01, is there some kind of compatibility table like we used to use for transistors. I haven't found a replacement for under £8 which seems daft. If I just wanted to fix it I'd just replace it with diodes but I'm trying to keep it authentic.Just what's the point of diode bridges when they work out 50x more expensive than using the equivalent diodes...... rant over!

author: fzabkar
author_rank: Super Contributor
timestamp: February 05, 2019, 02:38:48 am
content: The PW01 has an 8A, 100V rating. The equivalent is KBPC801 (100V), but the KBPC808 should be OK (800V).https://uk.rs-online.com/web/p/bridge-rectifiers/1695828/http://www.farnell.com/datasheets/2244564.pdf

author: PKTKS
author_rank: Super Contributor
timestamp: February 05, 2019, 11:36:58 am
content: Similar to the GBU810 (aka GBU8L) which is 1000V 8A rated (Diodes Inc.)Very easily found on AliExpress in the cloned PANJIT manufact.Paul
AGILENT U1233 issue - Page 1
Forum section: electronics / repair

author: maker
author_rank: Newbie
timestamp: January 26, 2019, 03:59:34 pm
content: helloi have issue with this multimeter,i bought it from ebay..it should give numbers when it get switched on however you only see slashesas you will see in the video, any help would be greathttps://youtu.be/hVWyEGDx80E

author: retiredcaps
author_rank: Super Contributor
timestamp: February 07, 2019, 05:20:26 am
content: Return it.
Super useful - cheap repair aid - LCR thermochromic sheeting cross post  - Page 1
Forum section: electronics / repair

author: cdev
author_rank: Super Contributor
timestamp: February 04, 2019, 08:35:02 pm
content: A number of times I've posted about the usefulness of thermal imaging sheets, in troubleshooting. especially in conjunction with an adjustable bench supply with current limiting..I just made apost in Thermal Imaging about this, but I'll also post their contact info here.They are a UK/US family owned company and very nice people and I give more info in the other post but just so there is a post here in repair their web site ishttp://www.hallcrest.comThere should be a sticky about this as its that useful a technique.LCR Hallcrest LLC - US1911 Pickwick Lane - Glenview, IL 60026847.998.8580sales@hallcrest.comcustomerservice@hallcrest.cominfo@hallcrest.comLCR Hallcrest Ltd – UKRiverside BuildingsDock RoadConnah's QuayFlintshireCH5 4DS+44 (0) 1244 817107salesuk@hallcrest.com
Diode replacement - Page 1
Forum section: electronics / repair

author: JFerris321
author_rank: Contributor
timestamp: February 04, 2019, 01:56:27 am
content: Hi, as a hobbyist with no real training I just wondered if anyone could give me some advice on a repair I am attempting on an amplifier main board in a Sony speaker system.I have established that there is a short on the 5v rail of the board and having probed around to find the lowest path of resistance (almost 0 ohms) to be on a Schottky diode SS34B as I have none of these to replace it with but do have some B340A's which have very similar characteristics, does anyone know if this would make a suitable replacement or am I best buying some of the correct part in?

author: Armadillo
author_rank: Super Contributor
timestamp: February 04, 2019, 02:06:40 am
content: I would say is just manufacturer numbering system. Good Replacement, Good to go.Edit: Of course, one of them is 1mm longer in length [SMA vs SMB]

author: JFerris321
author_rank: Contributor
timestamp: February 04, 2019, 12:19:47 pm
content: Thanks for the response, and jackpot my Sony GTK-XB7 is fully working.Cheers again.
(FIXED new battery woW) UNI-T UT204A Clamp Meter problem need fix  - Page 1
Forum section: electronics / repair

author: Mkdsime
author_rank: Contributor
timestamp: February 03, 2019, 08:29:14 pm
content: Hi i have UT204A clamp meter it fell softly and now when i press the select or rel or hold button it beeps sometimes display goes crazy and shuts down. I have cleaned the connections on the pcb, measured the transistors with diode test directly on the board all 'Y1' SMD transistors have short between 2 pins. What could be the problem if someone knows please help somehow thanks and take care.here is a video of it:https://youtu.be/luY6mjhX_-Qthis is a image when i press the select button it beeps screen goes all in and goes to the 1st measuring unit selected with the wheel

author: Mkdsime
author_rank: Contributor
timestamp: February 04, 2019, 10:44:13 am
content: so i bought brand new battery and it worked wowthe battery inside was 8.9V I've tested it with 9.2V both are cheap batteries and now change it with branded one 9.7V fully chargethanks to everyone seeing this post and to mr. "jutt engineer" on youtube
Samsung HL61A750A1FXZA LED DLP TV repaired - Page 1
Forum section: electronics / repair

author: james_s
author_rank: Super Contributor
timestamp: February 04, 2019, 04:29:59 am
content: My mother's Samsung TV croaked the other day, this LED DLP set is almost exactly 10 years old but still in good shape. Worked in the morning then she turned it on later and the red LED would blink but the screen never lit up.Pretty quickly discovered that the 16V DC-DC converter that powers the light engine had no output. The main converter IC as well as a small SMPS IC that provides power to that were both dead, 33 ohm fusible resistor open. I replaced the ICs and powered it up on the bench, output looked good. This board takes ~380VDC in and puts out 16VDC at a good amount of current. Seemed good so I put it back in the TV, hit the power button, BANG! The little IC and the fusible resistor exploded, main converter IC also checked bad again. Did more poking around, discovered that the main bulk filter capacitor was completely open, desoldered it and a pin fell off. I replaced that and replaced the ICs and resistor again, this time the TV powered up and is working fine again.Apparently what happened is with the bulk filter capacitor doing nothing, the inductance of the 3 feet of wires between the DC source and this board formed a boost converter that exceeded the max rating of the IC. Should have tested all the capacitors to begin with but it's rare that I find a big bulk filter to be bad. Anyway with a little luck this thing will go another 10 years.

author: highdesert56
author_rank: Contributor
timestamp: February 04, 2019, 07:38:39 am
content: Good info, thanks for sharing.Isn't that fun when things test good on the bench only to blow up when put back together?At least it didn't take even more stuff with it.
EPSON V39 Scanner Carriage Repair - Page 1
Forum section: electronics / repair

author: pedroantonio
author_rank: Newbie
timestamp: February 03, 2019, 11:45:02 pm
content: Trying to find out how to remove theEpson V39 Scannerglass to access the scanning wand/carriage...my nephew dropped the unit and the scan wand's carriage, which normally travels the entire length beneath the glass upon power-up, lights and tries to initiate a functionality test, but now the carriage only moves a few inches and then stops. I managed to remove the screws and plastic edging on the head and foot of the unit, but the glass won't slide out from the side rim slots, which appear to be cast as part of the body(?)...they don't seem to be attached with any screws I can find.Not sure if the teeth on the gear attached to the wand are possibly chipped?...or maybe the wand carriage was knocked off it's runner tracks?...the ribbon's stuck or misaligned? Epson's repair manuals are apparently proprietary and only released to authorized service centers.The unit's not worth sending it out for repair, as that'll cost me considerably more than just going out and buying a brand new scanner...but it seems a shame to trash a previously great working unit if one slight adjustment will restore it to its former excellent performance.Any help would be greatly appreciated.

author: amyk
author_rank: Super Contributor
timestamp: February 03, 2019, 11:57:37 pm
content: Some actual pictures of the unit would be more helpful than posting the marketing material...It might open from the bottom instead of the top.

author: Armadillo
author_rank: Super Contributor
timestamp: February 04, 2019, 12:04:14 am
content: Should be driven by steel wire belt, coil in rect & X shape.
Help with identification of diodes. - Page 1
Forum section: electronics / repair

author: Aglovale
author_rank: Newbie
timestamp: February 02, 2019, 08:37:27 pm
content: Hi there all. I'm a complete novice to electronics (although I am slowly learning basics) and I need some help with identifying these diodes.The first image is a hard drive PCB. The purple diode has: QA RA13 code and is approx 4mmx2mm. The red diode has: 12T 09 code and is approx 4mmx2mm.The second image is a mini PC. The orange diode has: J1 2 (2 is written sideways) and is approx 2.5mmx1mm.My own research tells me that the hard drive diodes are tvs diodes therefore, I presume that the 12T would stand for 12v tvs? and I read that the QA on the second diode normally means 5v?.As for the mini PC, I have no idea.Can anyone help me identify these diodes so I can purchase replacements?Thank you(Images are in attachments)

author: fzabkar
author_rank: Super Contributor
timestamp: February 02, 2019, 09:33:49 pm
content: QA is a 5V TVS diode.12T is a 12V TVS diode.TVS Diode FAQ:http://www.hddoracle.com/viewtopic.php?f=100&t=86J1 could be an N-ch MOSFET (BSS138LT1):http://www.s-manuals.com/pdf/datasheet/b/s/bss138lt1_on.pdf

author: Aglovale
author_rank: Newbie
timestamp: February 03, 2019, 12:49:50 pm
content: Thank you for your reply it was most insightful. I know nothing about mosfets so the link you posted with all that information is very helpful.

author: Aglovale
author_rank: Newbie
timestamp: February 03, 2019, 02:40:02 pm
content: May i ask your help with 1 more smd.Image 3 says: 30.000109There is also a symbol: a diamond shape with a bold T in the middle (I don't think you can see the code via the image unfortunately).Approx 4.5mmx3mmIs this a diode - does the 30 stand for 30v?

author: fzabkar
author_rank: Super Contributor
timestamp: February 03, 2019, 08:01:51 pm
content: That's a 30MHz crystal.

author: Aglovale
author_rank: Newbie
timestamp: February 03, 2019, 08:18:16 pm
content: Quote from: fzabkar on February 03, 2019, 08:01:51 pmThank you so much, I really appreciate your help.
AVR Subwoofer Pre-out Boost Modification - Page 1
Forum section: electronics / repair

author: highdesert56
author_rank: Contributor
timestamp: February 02, 2019, 10:01:17 am
content: Hey guys,I've got a new one. While I have this thing apart (Yamaha RX-A2070) I'd like to see if it's possible to boost the subwoofer output in the pre-out circuit.It seems I have to turn up the output more than I should and much higher than with my previous AVR (Yamaha HTR-6090). All tuning and crossover possibilites have been accounted for and it just seems that the sub-out is generally weak.Any of you audio gurus feel free to peruse the included scematic and let me know if I'm crazy or just stupid.Thank you.

author: tooki
author_rank: Super Contributor
timestamp: February 02, 2019, 07:13:19 pm
content: Surely the channel level is something you can adjust in the settings??

author: tooki
author_rank: Super Contributor
timestamp: February 02, 2019, 07:18:01 pm
content: Yep. P.146 in the manual:https://usa.yamaha.com/files/download/other_assets/4/957664/web_YJ291A0_EN1_RX-A3070_2070_om_UCRABGLF_En_A0.pdf#page146

author: highdesert56
author_rank: Contributor
timestamp: February 03, 2019, 12:53:42 am
content: Thank you for the response, sorry I wasn't clear enough.I have to almost max out the channel level to get somewhat satisfactory performance.The subs in question are PB16-Ultra and PB13-Ultra which took way less channel level and gain on the subs with the old receiver.So, I wasn't sure if I could sneak a resistor or two of a different value in there to spice things up a little.
Broken Quasar VCR Power Supply Noise - Page 1
Forum section: electronics / repair

author: cplusplus
author_rank: Newbie
timestamp: February 01, 2019, 11:51:37 pm
content: Hi all,I have a Quasar VH5145XQ VCR that will not power on. There is a buzzing noise coming from the power supply that I've captured in the following video:(Volume warning!)Is this noise coming from the transformer or one of the capacitors?Many of the capacitors on the board are bulging and will need to be replaced.Thank you.

author: Psi
author_rank: Super Contributor
timestamp: February 02, 2019, 12:08:03 am
content: Sounds like transformer to me.Switchmode probably keeps starting up, sensing a short and powering off.If your lucky it's just the bulging gaps that's the problem.But i wouldn't run it for long with it in the current state. May cause more damage.

author: Armadillo
author_rank: Super Contributor
timestamp: February 02, 2019, 12:12:35 am
content: What's that box thing above the transformer?

author: cplusplus
author_rank: Newbie
timestamp: February 02, 2019, 12:33:14 am
content: Quote from: Psi on February 02, 2019, 12:08:03 amYeah I saw some pretty dark spots on the PCB, so I'm not sure if its too late. This isn't worth much, I just bought it for learning purposes.Quote from: Armadillo on February 02, 2019, 12:12:35 amI'm not sure. I've attached an image of it. It might just be there to provide support for the bonnet?EDIT: I should note that in the video I plug the power in and then unplug it.

author: mzacharias
author_rank: Frequent Contributor
timestamp: February 03, 2019, 08:49:32 pm
content: Usually capacitors, mainly in the switchmode secondary. It's important to replace with low ESR, 105 degree rated caps of high quality.IMPORTANT: Unplug and do not run the vcr until the caps are replaced. Left unattended, the caps will lead to a failure of the switching transistor, and likely other related parts.Discharge all the caps before you go to replace them. Even one or two smaller ones may hold 40-50 volts and startle you with a spark, and the larger one in the primary may hold 160 volts or more.

author: cplusplus
author_rank: Newbie
timestamp: February 05, 2019, 12:25:08 am
content: Thank you! I've been buying Nichicon or Panasonic caps rated for 105. In regards to ESR, is there a way to calculate or gauge this? I've been ordering via Digikey and the ESR field is usually blank.
Hantek DSO 5072P - Page 1
Forum section: electronics / repair

author: Cubbie
author_rank: Contributor
timestamp: February 05, 2019, 01:00:44 am
content: Well after 2 years my Chinese scope finally started acting up. Self calibration fails at step 34 error 0x20001.Have no idea what that means.Also the trigger does not seem to work (horiz. rolling waveforms both channels) and because of that the autoset function does not work correctly.I have checked all voltages on the pwr. supply and the mainboard regulators. Also checked voltages on some chips in the trigger area thanks to the schematic posted by Tinhead.I have been looking for poor solder joints with magnification also.New firmware updates just fine. Scope has not been hacked to 200Mhz.Only problem I found so far was the CR2025 backup battery is dead. I replaced it with a CR2032.Any ideas would be greatly appreciated, Thanks.......Jim

author: PKTKS
author_rank: Super Contributor
timestamp: February 05, 2019, 11:39:57 am
content: These highly miniaturized SMD things are anything but easy to deal.Old scopes are still serviceable...I have plenty of doubts putting my moneyon this new FPGA based boards...Paul
Electric Chair malfunction with remote control CIAR - Page 1
Forum section: electronics / repair

author: CKCONE01
author_rank: Newbie
timestamp: February 02, 2019, 07:08:06 am
content: Hello,I have a chair with a command module and wired remote control .the remote control does not work anymore .i have opend the electronics and a capacitor was blowned up in the beginning of the supply chain . i have renewed it and now in the second print the lm7038 becomes very hot and the remote still thas not work .is there an electrical diagram for these two prints or assistance where to search for components that are defective ??thanks in advance Chris
Repair FFC with very fine traces - Page 1
Forum section: electronics / repair

author: endlessmind
author_rank: Newbie
timestamp: February 02, 2019, 12:52:49 am
content: Hi.I recently got my hand on a high-end Samsung QLED 65" from 2016 for free that had been dropped.The only issue, was that a smal piece of the FFC thats bonded on the display was ripped (about 5-6 traces on 5mm)that had caused horizontal rows of about ~20 pixels to be off (~20 off, followed by ~20 pixel on and repeat).When gently pushing the ripped part back to where it belongs, the dark rows turned on again, (hurray!).I currently have it pushed in place by a smal piece of tape with the adhesive side facing away from the FFC (to avoid causing more damage when removing)and I would like to re-attach the traces somehow.I might be possible to solder them with tiny wires without totally messing with the signal integrity, but I would have to get a good microscope and a micro-tip for the iron and more.Is there some kind of ACF tape or similar that don't require lot of heat and pressure that can be used or does anyone have any other suggestions on how to fix this?Thanks in advance!

author: jeremy
author_rank: Super Contributor
timestamp: February 02, 2019, 03:38:58 am
content: https://www.adafruit.com/product/1656Perhaps?

author: KL27x
author_rank: Super Contributor
timestamp: February 02, 2019, 04:32:13 am
content: QuoteEquipment upgrade subsidized by a free TV? Sounds like a win-win. 0.5 mm pitch is doable. Depends on how much ribbon you have to work with.Is the ribbon soldered to a rigid pcb on both ends? Or is there a connector on one end? And is it standard? I'm sure you have considered all the angles, but if you took a picture, maybe someone will have an idea you haven't considered. Ribbons like this can be hand patched, as long as you can get it out to where you can work on it. Fixing something like this in situ is another level of difficult.QuoteThat's cool stuff. Sorta like those rubber things that some LCD's connect thru by pressure. Too bad it's not X or Y axis tape. That would be just the ticket for this. Maybe that's coming, next.

author: Armadillo
author_rank: Super Contributor
timestamp: February 02, 2019, 04:44:01 am
content: I won't try even under heavy microscope.Use proper tool ACF, heat and pressure + alignment gear.

author: endlessmind
author_rank: Newbie
timestamp: February 02, 2019, 12:18:35 pm
content: I think @Armadillo is correct.Took some pictures (attached) and added some back light to get a good look at the traces.There is no-way I can hand-solder them, not even the awesome 3M tape will be able to fix this.I might be able to find some local place that has the ACF gear and can do it,but then I would have to be able to find an new FFC cable.I guess I'll have to live with my how-you-doin' fix at least for now.