hybridfree/eevblog-posts huggingface dataset:
Samsung 64in Plasma Power Supply Repair - Page 1
Forum section: electronics / repair

author: Basstrom
author_rank: Newbie
timestamp: October 10, 2018, 12:12:41 am
content: Hi all,First time poster here.I've got a Samsung 64in Plasma TV that the power supply board has died in it (something common with these). In my research of what actually fails I've found that the MOSFET's on the power factor correction circuit (this I'm guessing from similar boards and proximity of the MOSFETs to the 400V caps).The part number for the MOSFETs on my particular board are K18A60V. A quick google search and hunting on Digikey and Element14 reveals that these are obsolete or I can get cheap "wun-hung-lo" parts from Aliexpress / eBay, I'd rather pay extra so it doesn't fry the rest of the TV.So... my question is, how do I go about finding a suitable replacement?From the datasheet I was able to find it has the following characteristicsN ChannelVds - 600VId - 18ARds On - 190mOhmsVgs - 30VPd - 45WPackage - TO-220I can't find something that meets the exact same specifications, unless I'm not searching correctly on Digikey / element14.What characteristics can I be more "lenient" on, ie could I use one with an Id of 20A instead or Vds being 650V?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 10, 2018, 01:38:35 am
content: The only one ive found: sure there maybe other equivalents,the 600v is the determining / choosing factorYou could search in the 2SK series, IRF series ....Manufacturer: IXYSPD VDS VGS VGS(th) ID TJ TR CD RDS CaseIXFP22N65X2 N MOSFET 390 650 30 5.5 22 150 35 1530 0.16 TO220ABIXFP24N60X N MOSFET 400 600 30 4.5 24 150 29 1400 0.175 TO220ABIXTP32N65X N MOSFET 500 650 30 5.5 32 150 49 1600 0.135 TO220AB <-------------------------------------- this one is the winnerMouser sell these's, not sure you have it in your country ? around 6$ usdhttps://www.mouser.com/ProductDetail/IXYS/IXTP32N65X?qs=O0OZL7qk7VFfC1DWhVylYw==EDITFOUND THIS SEARCH TOOL :http://uk.rs-online.com/web/c/semiconductors/discrete-semiconductors/mosfet-transistors/?searchTerm=mosfet

author: Basstrom
author_rank: Newbie
timestamp: October 10, 2018, 07:35:07 am
content: Thanks for that mate.One thing I noticed when taking off the old parts, there is no metal pad on the back, so I'm guessing they're electrically isolated from the heat sink as they are both mounted on the same heat sink with a 2206 Twin diode in the same package.Would these be suitable instead?https://docs-emea.rs-online.com/webdocs/1670/0900766b8167035e.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: October 10, 2018, 10:09:12 am
content: I think they can do

author: Basstrom
author_rank: Newbie
timestamp: October 11, 2018, 07:38:59 am
content: Cheers,I ended up getting another brand new board in the mean time, but considering the failure rate of these boards based on google searches I'll keep the old one and fix it up.Thanks again for your help
Hirose FX2BA ribbon connectors - Page 1
Forum section: electronics / repair

author: sarason
author_rank: Contributor
timestamp: October 10, 2018, 08:16:25 pm
content: I am attempting to repair an Agilent E4400 series Spectrum Analyser. To repair the main board I need to extend it out of the chassis onto the bench.To do this I need to make some ribbon cable Extenders using Hirose FX2BA M/F 68 pin connectors as well as 2 each of FX2BA M/F 100 pin connectors.The 68 pin connectors were used by some SCSI cables in days gone by in equipment like HP server Chassis's.Owe and some of 100 wire ribbon cableNow does anyone in Melbourne have any I can borrow or buy?Is there an equivalent from another manufacturer?Any other brilliant and insightful advice?regards sarason

author: Astrodev
author_rank: Regular Contributor
timestamp: October 11, 2018, 12:06:57 am
content: I know most of the Dell 2800 series and earlier servers used the 68 pin cables internally but they will probably be M/M, but if you can use one of these instead of the installed cable plus extender it may be a solution and I would expect you could pick one up fairly cheaply on the used market.However the 100 pin is more of a problem.
Full Wave SCR/Diode bridge failure? - Page 1
Forum section: electronics / repair

author: tarogers
author_rank: Newbie
timestamp: October 06, 2018, 03:40:14 pm
content: I have a Kohler 6 KW AC generator on my boat that now shuts down immediately after startup with an over voltage error code. The voltage regulator consists of a printed circuit board driving a full wave SCR/diode Bridge, driving the generator field.The SCR/diode bridge passes all of the ohm meter tests with the possible anomaly of the gate to cathode resistance on one SCR is 3 ohms and the other is 30 ohms. Using an external 9 volt battery and bulb both SCR’s block and then fire with a gate signal.I reconnected the bridge to the generator, but left both gate leads off. I fired up the generator and still got an over voltage shut down. I then removed one AC input lead from the bridge and got an under-voltage trip upon startup.This leads me to believe that one(or both) SCR’s are self triggering causing over excitation of the field and the over-voltage shutdown, though they seemed okay with the low voltage DC test.Since the bridge itself costs about $60. I thought I would get a second opinion from The Forum before proceeding.Thanks,Tom

author: coromonadalix
author_rank: Super Contributor
timestamp: October 07, 2018, 05:05:07 pm
content: I would remove the scr assembly and test it ... since you have the basics on how to test scrs, you test them non triggered to check against leakage, normally and polarity inverted, after that step you trigger them and check them again, the best tester i had in the past was applying ac and dc voltages and read it with an oscilloscope, i could see leaking diode and src's, when we test in DC it may be okay, but i've seen in the past some leakage in ACOnce in a while in our board cleaner we have to change some opto coupled src bridge, they simply go bad, the only trick we have is to get an stronger spec in current to overcome this phenomenonwe use normally 50 amps ones, but now we install 75 amps, and they cost almost 100$ a piece.On google you have :http://www.circuitstoday.com/how-to-test-an-scrhttps://sciencing.com/test-scr-ohmmeter-6681788.htmlhttps://www.androiderode.com/how-to-check-a-scr-with-digital-multimeter/http://www.completepowerelectronics.com/how-to-test-scr-with-multimeter/You can try to find your scr(s) part number(s) to see their specs ?Unless you have the scr drivers who can go bad ? maybe you have some diacs / optocouplers etc ... for the gate drive ?

author: tarogers
author_rank: Newbie
timestamp: October 10, 2018, 07:38:21 pm
content: Thanks for the thorough reply. I will remove the bridge this weekend and further bench test it.One curious point is Kohlers test instruction:"6. Connect the ohmmeter from G1 to (+) on the SCR module. You should read low resistance in both directions. Repeat for G2."I would expect to see a diode like set of readings for a gate to cathode test.One SCR reads 3 ohms in both directions, and the other 30 ohms in both directions.I'll verify when I get it home.
Help Id two IC's - Page 1
Forum section: electronics / repair

author: vsboost
author_rank: Contributor
timestamp: October 08, 2018, 11:56:16 pm
content: Hi Gang,Could anybody please help ID these two IC's, they are from two separate keyfob transmitters, i cant find any info/datasheets for them.I believe they are manufactured by motorola and are tssop-16 packages.Cheers

author: coromonadalix
author_rank: Super Contributor
timestamp: October 09, 2018, 12:44:55 am
content: I think they are proprietary chips, every google search numbers gives false / shitty links ....

author: vsboost
author_rank: Contributor
timestamp: October 09, 2018, 12:47:49 am
content: Thanks for trying, seems like many keyfobs have these proprietary chips in them.

author: SMdude
author_rank: Frequent Contributor
timestamp: October 09, 2018, 01:31:56 am
content: Are you sure it is the IC you need?Is there a crystal oscillator? And if so is it working?What is the problem with the FOB's?

author: vsboost
author_rank: Contributor
timestamp: October 09, 2018, 01:39:40 am
content: The IC's are fine, i was just curious about the parts in question and how they work and are programmed etc.. One of the fobs does have a problem the OOK data is being emitted from the IC and makes its way down to the resonator however after that i believe there might be a problem with the output power transistor because i cant receive any RF (using a SDR to test) What i did notice was when i probed a resistor with my tweezers i could see the OOK RF data on the SDR very low power, the tweezers were probably acting like an antenna i suspect.

author: CJay
author_rank: Super Contributor
timestamp: October 09, 2018, 06:16:11 am
content: Post a pic of the full board?I've had similar problems with GM/Opel keyfobs, turned out to be the RFM1000 module in mine but I 'fixed' it by cloning the fob.

author: vsboost
author_rank: Contributor
timestamp: October 10, 2018, 02:30:34 am
content: Here are the pics.One of the via's was corroded, had to run a jumper through and run to the 104 resistor that connects to the IC, once this was done the fob leds started blinking again.The 393 resistor near the p21 transistor seemed to have a crack on it that's why it looks funny as i removed it to inspect it better, it measured fine and was put back in.When i was probing with tweezers around that area i could see the RF signal on the SDR it was very weak however, which leads me to believe the signal was getting to that p21 transistor which i can only assume is being used as an amplifier, but now i cant even get it to do that, must have killed something in the process.
A classic reminder.... - Page 1
Forum section: electronics / repair

author: peteb2
author_rank: Regular Contributor
timestamp: October 11, 2018, 09:19:29 pm
content: By way of a tangled path an item comes to you because "i hear you can fix gear'. The story unfolded the unit (a sound process device) had stopped working suddenly after the power supply electrolytic capacitors had already been changed by another tech and that had let it work for a few more weeks but now it'd gone dark....So you have a look and soon find the switchmode has another nasty little issue. It's covered in gobs of assembly goo that has plainly turned brown and become conductive. It's an unusual module with +/-15V, 5V & 3.3V with integral IEC mains connection socket.So here was my mistake: Taking at face value from the owner's assurance the unit actually, truly, really worked....FULLY.In a proper world i would have set up my own set of supply voltages and made sure there wasn't any chance of a gotcha.... I didn't .... (so there's your reminder for the day).Instead i spent a couple of hours on the SMPS , removing parts & scratching away the conductive goo and then soldering them back in place. Even the output loom had been coated in the goo and the strands of wire were corroded from the it so nipped the ends and re-terminated everything.So finally i'd a fully working SMPS with proper clean voltages but powering up the unit ... oh dear. The display lights, selections can be made but it doesn't do a thing. It can't even be programmed .... and the owner says now they just gonna buy something new....And so there's your second reminder.... Make 100% certain the party whose bought you a 'thing' to fix because they're 'desperate' understands exactly what your deal is and what to expect or you are simply gonna be the loser.... (on this one i get to have a bleat here).

author: SilverSolder
author_rank: Super Contributor
timestamp: October 12, 2018, 02:15:03 am
content: Sounds like a case of "Beyond economical repair"? Can be hard to spot without digging a little, of course.
Sony ICF pro 80  need help ! - Page 1
Forum section: electronics / repair

author: Tomyx
author_rank: Newbie
timestamp: October 07, 2018, 08:04:53 pm
content: Hello,I have bought a "for parts or repair" Sony ICF pro 80 radio from ebay that had no sound at all. Since this is a common problem for those kind of radios due to bad caps i knew what the problem is.So i replaced all the caps in the radio in total 18 pieces. and i restored the audio but only on FM band... on AM is still dead. Only in mode "narrow" AM have sound but only hissing.So i request some help from someone that knows how a PLL radio work and where to check or what may not work properly.I have the service manual... but i don't have a oscilloscope.P.S. I managed to successful repair another 2x icf pro 80 by replacing the caps... but this one is driving me crazy

author: orbanp
author_rank: Regular Contributor
timestamp: October 09, 2018, 09:20:02 pm
content: Hi Tomy,I helped a friend some years ago to fix his Pro80 - he had some bad PCB around the audio amp, and some bad coils, the quadrature decoder coil, and one of the FM-band coils.So I would say I am fairly familiar with that radio.I would be glad to help you!Send a PM with your e-mail address, the repair could get long!Regards, Peter
hp 54601a nvram substitute - Page 1
Forum section: electronics / repair

author: nixiefreqq
author_rank: Super Contributor
timestamp: October 10, 2018, 12:33:27 am
content: just acquired an hp54601a. it was 100% functional and in great shape.BUT the dallas 1220 nvram had a date code of 1992.wanted to replace the dallas chip with an eeprom but it appears a suitable one is unobtainium.went ahead and substituted the dallas chip with standard static ram, a battery controller chip, and a coin cell.also installed a 24 pin socket so that i can test an eeprom if any can be found.calibration went well and the scope is 100% again (and its an easy fix when the coin cell dies).vertical cal was easily accomplished with the built in dc calibrator (bnc on the rear panel).delay cal was also easy but requires the use of a 100khz, pulse generator signal with <5ns rise time.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 10, 2018, 01:51:45 am
content: Someone took a chance with an Cypress FM18W08, made an pcb adapter :https://imgur.com/a/GmKHW4cand another one talk about an 28c16 taking the place of the Dallas :http://www.repeater-builder.com/motorola/maxtrac/replacing-dallas-nvram.html

author: John.S
author_rank: Contributor
timestamp: October 10, 2018, 08:29:41 am
content: Hi,A full replacement for the EEprom module is the M48Z02-70PC1 from Micro Electronics.Mouser has 400+ in stock ( order nr. 511-M48Z0270PC1).gr. John
Agilent U8002A Power supply input binding post mountings - Page 1
Forum section: electronics / repair

author: JohnPi
author_rank: Regular Contributor
timestamp: October 05, 2018, 10:15:48 pm
content: The binding posts on my new (to me) U8200A wobble -- this is because the small internal PCB they are mounted to only has one screw holding it in place. There is a second mounting post and hole in the PCB, but no screw. In addition, this 2nd post is different from the first (it is narrower than the PCB hole) so it won't hold the board's vertical position anyway.Is this normal ? Does anyone have a photo of that area in their unit (or U8001A which I suspect is similar) ?

author: xavier60
author_rank: Super Contributor
timestamp: October 06, 2018, 03:22:25 am
content: With my U8002A, although the screw is not present, the end of stand-off has been machined to fit in the PCB hole.This would be preventing the PCB from pivoting around.The terminals do wobble up and down by a small amount, only within the clearance of the holes in the front panel.

author: JohnPi
author_rank: Regular Contributor
timestamp: October 06, 2018, 03:51:23 am
content: Thanks -- that just looks like mine. It's not that it pivots; it's more like it flexes up and down.Note the unused shaft is threaded (M3) just like the one that is used on the other side. I put a sleeve over the shaft (just a little shorter than it) and used a screw. It doesn't seem to make much difference to the wobble however.I wonder why they designed it this way.

author: xavier60
author_rank: Super Contributor
timestamp: October 06, 2018, 04:20:00 am
content: I had added a bit extra to my post."The terminals do wobble up and down by a small amount, only within the clearance of the holes in the front panel."
Glitch trigger error when running field adjustment on a TDS784D - Page 1
Forum section: electronics / repair

author: JimS
author_rank: Contributor
timestamp: October 08, 2018, 08:40:49 am
content: I have a issue with my converted TDS784D (was a TDS754D)My problem is when running the field adjustment program.Doing a full seq adjustment, everything went ok up to Glitch Trigger cal.And the rest of the adjustment's after that run ok.The adjustment errors on T1 and T2 Slow Ramp Kramp adjustment with 1 Mhz input.The two steps before that pass ok, 2.5 Mhz & 13.889 Mhz input.(I'm using a Fluke 5820A W/Ghz option for my signal sources.)After it fails the first time and I run it again there is a message about needing repair.I have tried numerous things to get a better feel for what exactly is failing and why.Tried changing the freq to 990, 995 & 999 Khz to see what the effect is on the failure.The errors are any where from Countoffset, illegal dac value 1 to T1 Slow Ramp Tflop.I don't normally do any Glitch triggering with my TDS scope.A short history of this scope project-Originally this TDS754D had a blown P/S, the main filter cap was open & it even rattles when shaken.(not stirred)It sat on a shelf for 2 or so years.In the mean time my TDS784A had problems turning on but not working.It's P/S had 4 caps that decided to be incontinent and wet the PCB.Re-capped the P/S and all was well, until the input 1 & 2 attenuator assy's started to misbehave when set to below 200mv.I swapped the input attenuator assy with another one from another dead TDS784A, so far ok.Then being the good little $%#@! that they are, input 1 relays decided to do the same thing again.I got the dead TDS754D's owner to give me the scope so I could upgrade it to 1 Ghz.Thanks to the people here that posted how to do this...Thank you!!Swapped the P/S, changed the ID resistors and then enabled the 2M and 2C options.Fortunately it has the new style CPU & Acq boards.)Any way...Any help, information on what is happening & why etc would be greatly appreciated.J_SUpdate>I disabled the 2C 'comm' trigger option.Ran the Glitch trigger cal again, it failed.Ran it again and when it got to the Slow Ramp cal with 1 Mhz input.I set the freq. to 995 Khz and set the vert B/W to 250 Mhz.It passed both T1 and T2 slow ramp cal with the 995 Khz input.But... Murphy doesn't like perfect endings, the pulse trigger cal status still shows running.Ideas on this new situation?
Texas Instruments Collegiate (SC-10?) calculator repair. - Page 1
Forum section: electronics / repair

author: Refrigerator
author_rank: Super Contributor
timestamp: September 08, 2018, 07:27:07 am
content: I bought myself a TI Collegiate calc at the flea market today, i'm pretty sure it's the SC-10 but mine has "collegiate" written where you'd otherwise find the SC-10.During exams in my university they don't allow calcs like my TI-82, and i thought i could use this calc.Paid a whopping one euro for the thing but it doesn't work, once i put in the batteries it displays a zero (?) on the screen but does not react to any button presses.It's serial No.988 so it's one of the first thousand made, which makes me want to fix it even more.Currently i have not done anything to it besides put in some fresh batteries, because i'm not sure how the thing comes apart and i don't want to wreck it.Also the half of the case with the display is bulging out, i'll upload some pics.

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 11, 2018, 12:06:36 am
content: I don't dare give any advice on how to open the thing neatly.I'm betting on a broken FFC in the hinge not quite sure how that should affect the LHS of the keyboard though.http://www.datamath.org/Sci/Modern/JPEG_SC-10.htm#internal

author: xrunner
author_rank: Super Contributor
timestamp: September 11, 2018, 12:14:24 am
content: If I had to guess I'd say the top and bottom of the case snaps together - never to be taken apart again. But if you want to try, you'd have to find the right area to pry it apart, which in turn might muck up the plastic.Good luck.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: September 11, 2018, 12:24:36 am
content: Quote from: xrunner on September 11, 2018, 12:14:24 amYes clipped construction seems likely. Finding the clip locations with a soft plastic pryer seems most sensible approach.It might be the taps will be damaged as result but it is a risk you might have to accept in case you wish to repair the unit

author: Refrigerator
author_rank: Super Contributor
timestamp: October 07, 2018, 07:18:05 am
content: Yep the calculator clips together. I took it apart to check the insides but it looks pretty clean, there's only one capacitor on the main board besides the main IC.There was some corrosion at the battery terminals but it was only superficial and cleaned off easily.The main IC looks like it has a crack running across it but i'm not sure. I think this calc might be beyond repair.Too bad because i really liked that funky slidy unit changer thingy.I'll upload some pics later.
Adjustment of bias and other VR's, portable amplifier. - Page 1
Forum section: electronics / repair

author: Ashhhhh
author_rank: Contributor
timestamp: October 05, 2018, 09:34:57 pm
content: Hi guys,I'm trying to resurrect a Lectrosonics Maxi Mouse amplifier.It was a bit of a basket case and is now up and running, I would like to adjust the bias next.Unfortunately the manufacture doesn't provide any details but I was able to search out a schematic.Would someone be kind enough to cast their eyes over it and give thoughts on the bias adjustment?In addition there are two other unlabelled VR's, one near the bias and the other near the charger input. It would be great to know their role and adjustment.Thanks!Ashhttp://cloud.tapatalk.com/s/5bb7d8f7a3717/maximouse__17049f_sch.pdfSent from my Pixel using Tapatalk

author: cvanc
author_rank: Frequent Contributor
timestamp: October 06, 2018, 12:26:51 pm
content: The 5K pot at the LM301 sets your output stage biasThe 25K pot near the loudspeaker controls how hard the audio compressor works (note the CLM50 optocoupler in 2 locations on the schematic - this is the compression control device)And the 25K pot in the power supply sets the power supply output voltage. BUT... are those batteries rechargeable while in the unit? If so you might have to set the 25K power supply pot to provide some specific charging current that the batteries would be happy with - you might do this by pulling the battery fuses and putting your meter (in amps mode) across the open fuseholder.Good luck.

author: commongrounder
author_rank: Frequent Contributor
timestamp: October 06, 2018, 04:14:04 pm
content: On a battery powered amp like this, there is often no emitter resistors on the output transistors to refer a set bias value to. If I were adjusting this unit, I would put a scope across the output, and feed in a mid to low audio frequency sine or triangle wave at a low volume. Then I would adjust the bias until the crossover notch in the waveform just disappears. That should give the best balance between distortion and power consumption(battery life). The service manual might have had a spec for current measured across one of the (empty) fuse holders as a way to arrive at a typical bias setting to avoid the need for a scope.Best of luck to you!

author: Ashhhhh
author_rank: Contributor
timestamp: October 06, 2018, 08:59:34 pm
content: Thanks to you both.Excellent, I'll use a scope and do exactly that.Any thoughts on adjustment of the compression pot?Yes, the batteries are charged within the unit, I just need to source a 20VAC wall wart.Quote from: commongrounder on October 06, 2018, 04:14:04 pmSent from my Pixel using Tapatalk
Vizio VO42L FHDTV10A - Blown Mystery Transistor on Power Board  - Page 1
Forum section: electronics / repair

author: Metal Beard
author_rank: Newbie
timestamp: October 06, 2018, 02:35:45 am
content: Hi Guys!I identified two blown components on the main power board for this TV. The power board # is DPS-260HP-1 AI have searched with no luck to find a schematic or component list for this board.I can buy a replacement board for about 40-50 bucks, but if all it needs is a few components, i want to put my skills to use and fix it!The first component was R919 which i believe was a 75 ohm resistor, i say believe because it had burned text that was hard to read, and read as open on a meter.The second component is more of a challenge. It's some kind of transistor, Q905. The problem is that it exploded.The top line where the component ID should be listed is literally gone. I can only make out F3 then either an M or N but it is cut off.Below that on the next line is either Q or 6, then gone.Bottom line of text is clearly an ST branding mark.My best guess is a STF3N62K3 which is a N-Channel Power MOSFET. But with out any kind of schematic, or knowing for sure, it's impossible to say.Any ideas?Thanks in advance for any help.Large pics in this linkhttps://imgur.com/a/atuHERk
. - Page 1
Forum section: electronics / repair

author: FRR
author_rank: Newbie
timestamp: September 14, 2018, 01:46:52 am
content: .

author: TiN
author_rank: Super Contributor
timestamp: September 14, 2018, 05:05:55 am
content: I maybe have one ADC but it need some parts (DG4xx switches and some JFET perhaps).Also it's a bad idea to power on meter with open traces in that area, because that part of circuit is bootstrap capacitor multiplier supply. Chances are that now you killed bunch of opamps/parts in input front end which uses boostrapped +38/-38V supply to provide high impedance input that this meter have.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 04, 2018, 10:37:46 am
content: Not sure i would go all the way to remove parts, you may create more problems, i would focus on the remaining problems if there is, after a good cleanup.You have good cleaning products who can go under the parts and do a very good cleaning.At my job we use liquid flux who goes everywhere, we rince to board fully after in de-ioniozed hot water with Atron SP200 and or Atron AC205, it remove any greassy stuff and flux residues, and with air spray we remove any water excess and put it in an pcb dryer.

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: October 04, 2018, 07:23:31 pm
content: Quote from: FRR on October 04, 2018, 06:23:01 amwell, unless you have definitive information on all exposed parts being suitable for ultrasonic cleaning, just don't do it.as coromonadalix already said, proper (and repeated) cleaning will most likely do the trick. i can confirm that from my own repair experience on several stone-old 200x units.patience is the key.

author: TiN
author_rank: Super Contributor
timestamp: October 06, 2018, 01:47:15 am
content: If that would be me, I'd go with desoldering/cleaning/soldering new components (not old ones! When not custom parts) path. With care and patience, it does not sound so bad. Also meter must need full recalibration anyway, so that doesn't matter anymore. 304.6/304.7 errors are often result of excessive board leakage, cleaning of ohms area and area around switches near LTC1043 may help on those.
Help Identifying a DC Connector - Page 1
Forum section: electronics / repair

author: DrDeke
author_rank: Contributor
timestamp: October 10, 2018, 07:42:12 pm
content: I have misplaced a DC connector which is needed to get one of my UPSes to work. I would like to order a new one, but I do not know what this type of connector is called. I have looked through some catalogs but not seen anything that looks similar. The distance between the center of the two pins in the connector is exactly 0.5 inches, but that doesn't help without knowing the name of the connector.Pictures of the connectors in question:Male #1Male #2Female #1Female #2If any of you know what kind of connector this might be, I'll be very grateful to hear it.

author: LapTop006
author_rank: Unknown
timestamp: October 11, 2018, 10:59:04 am
content: Are they essentially shrouded banana's in some form of holder? Possibly too small?

author: Nusa
author_rank: Super Contributor
timestamp: October 11, 2018, 11:08:04 am
content: I'd start with whatever web presence the UPS brand you didn't mention has. You never know, they might actually sell the cable you need. If not, one of their reps may be able to answer the question.

author: BradC
author_rank: Super Contributor
timestamp: October 11, 2018, 11:13:36 am
content: Looks like an MGE or Liebert battery bay shorting connector. I have searched for years for compatible connectors for both those and the 5 pin external pack connectors and got nowhere short of buying expensive second hand or surplus cables and cutting them up. I've never found a source for those shorting plugs other than the battery bay though.(edit : not shorting connector). I mis-remembered, it's the battery connector for the 72V packs.

author: bob225
author_rank: Frequent Contributor
timestamp: October 11, 2018, 11:34:28 am
content: They look like a older Anderson power plugedit number 7 as keep hitting reply instead of saveThe dc plugs are Wellshinhttp://www.wellshin.com.tw/en/m/eg. Sockets45 amp EM-02225 amp EM-0095 pin patch - WellShin PPC-25P-5ALI hope someone finds this useful,edit. 547 one of the distributors for wellshin ishttp://www.braemacca.com

author: DrDeke
author_rank: Contributor
timestamp: October 12, 2018, 10:33:08 pm
content: Quote from: Nusa on October 11, 2018, 11:08:04 amYeah, I suppose I should have mentioned that. It's a Liebert (later Emerson, now Vertiv) UPStation GXT2000RT-120. This line of UPSes has been discontinued for quite a long time and the brand has changed hands twice during that time, so I'm doubtful the company would be of much help. They'd probably suggest buying one of their new (and expensive) GXT4 series models.Quote from: BradC on October 11, 2018, 11:13:36 amYou hit the nail on the head; what I am specifically looking for is the battery shorting connector (connects the two 48 V strands in series to get 96 V after you have installed the battery assembly and are less prone to shorting or accidentally touching the 96 V). But I can build one of those if I can get ahold of the right connectors.Quote from: bob225 on October 11, 2018, 11:34:28 amPerfect, thanks - that's exactly what I needed! Much appreciated!
Tektronix TDS-540 Console Port? - Page 1
Forum section: electronics / repair

author: EB5AGV
author_rank: Contributor
timestamp: July 21, 2016, 09:45:30 pm
content: Hi all,I am working on aTektronix TDS540which, as most units, has some ACQ board problems. I have already carefully cleaned residue and replaced caps and have also removed some faulty opamps and TTL circuits, which will be soon replaced by new ones.But I don't know how to get into the serial console port for detailed troubleshooting. I have read about building an adapter. Could someone let me know how to do that?. My unit does not have Option 13. Should I have it?Best regards,Jose

author: picburner
author_rank: Frequent Contributor
timestamp: July 22, 2016, 05:51:03 am
content: Hi,this is the TDS console port schematic that I made several years ago:

author: EB5AGV
author_rank: Contributor
timestamp: July 22, 2016, 08:01:58 am
content: Quote from: picburner on July 22, 2016, 05:51:03 amThanks!. I will build one myselfIt will be a very useful tool to troubleshoot this unit, I am sure.Regards,Jose

author: piotekp90
author_rank: Contributor
timestamp: October 02, 2018, 09:37:09 am
content: Which port is a console port J37 or J40? I have read many topics about console port but I still don't know to which connector I should connect the converter. I see that orginal RS232 connection board is connected to J37.

author: picburner
author_rank: Frequent Contributor
timestamp: October 02, 2018, 10:29:56 am
content: J40 is the console port, J37 is reserved for opt 13 serial/parallel port.

author: piotekp90
author_rank: Contributor
timestamp: October 04, 2018, 08:47:27 am
content: I have redrawed your schematic and now I'm working on a PCB layout. Do I understand the J40 pinout correctly?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 04, 2018, 10:22:22 am
content: To be sure, while unpoweredCheck the grounds and data pins going to the mcu with an ohm meter if they are at the right pins would be a start ...

author: picburner
author_rank: Frequent Contributor
timestamp: October 04, 2018, 04:43:48 pm
content: J37?? I guess you meant J40.However the pins are marked right.Keep in mind that in my schematic U1 (MC68681FN) is in PLCC-44 not DIP40.

author: piotekp90
author_rank: Contributor
timestamp: October 05, 2018, 08:06:30 am
content: I meant J40 (sorry my mistake). I have prepared schematic for PLCC44 version like in your schematic.
Trying to replace a faulty thermal link/resistor - Page 1
Forum section: electronics / repair

author: XaviPacheco
author_rank: Regular Contributor
timestamp: October 01, 2018, 01:02:54 pm
content: Hi,I found this Thermal Link/Resistor A5MC-220JK to be open. I don't find the same replacement. Is there another way for me to replace it? I thought of a 22 ohms/ 2W resistor, but the actual protection wouldn't make sense then.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 01, 2018, 08:47:09 pm
content: you had an response on "all about circuits forums" why ask here ? lollsame response :https://www.digikey.com/products/en?keywords=285-1901-NDSince it has an 18week of lead time, put an 22 ohms 2w resitor in serial with an 139 degree thermal fuse, thermally glued or an shrink against the resistor.

author: XaviPacheco
author_rank: Regular Contributor
timestamp: October 01, 2018, 09:30:19 pm
content: Well.. I just wanted to hear a different approach from someone elseI needed a fast solution rather than waiting long only for that component. I just thought of putting the 22 ohms resistor without the thermal fuse. Of course, I know the consequences if it fails againA faulty bridge rectifier caused the thermal link goes away. I've replaced the bridge, I'm only stuck for that component, and I just have the 22ohms/2W resistor at the moment.

author: macboy
author_rank: Super Contributor
timestamp: October 03, 2018, 01:05:11 pm
content: Hmm, for me it shows:"Quantity Available 25,869 Can ship immediately "In this case, the manufacturer lead time is of no consequence, unless you need 25870 of them!edit: Apparently Arrow has free shipping worldwide on all orders no matter how small. Butbe prepared to receive a very large package for your one component.
IT 8987E, 1431 BXS - Page 1
Forum section: electronics / repair

author: Gabriel82m
author_rank: Newbie
timestamp: October 02, 2018, 10:45:29 am
content: ITEIT 8987E1431 BXSSC20LA

author: Gabriel82m
author_rank: Newbie
timestamp: October 02, 2018, 11:06:30 am
content: Quote from: Gabriel82m on October 02, 2018, 10:45:29 amAny one can help me to know how and where i can bye this IO chip?

author: Zucca
author_rank: Unknown
timestamp: October 02, 2018, 01:25:29 pm
content: Picture?

author: Gabriel82m
author_rank: Newbie
timestamp: October 02, 2018, 02:00:33 pm
content: thank youThis is pic

author: coromonadalix
author_rank: Super Contributor
timestamp: October 02, 2018, 09:54:41 pm
content: on ebay :https://www.ebay.com/itm/2-peice-New-ITE-IT8987E-BXA-ITE8987E-8987-IT8987E-BX-QFP-I-O-IC-chip-8987E-/182204818262Read this thread about it :https://www.eevblog.com/forum/repair/replacing-laptop-motherboard-super-io-chip-ite8987/

author: Rasz
author_rank: Super Contributor
timestamp: October 03, 2018, 04:20:31 am
content: neither number, you need programmed chip

author: Gabriel82m
author_rank: Newbie
timestamp: October 03, 2018, 06:19:29 am
content: I have seen this chip BXS in ebay that have nomberITEIT 8987E1506 BXSSC35UABut my chip nomber isITEIT 8987E1431 BXSSC20LAWhat do you think if i can bey this is it ok?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 03, 2018, 10:34:00 am
content: If the : ITE IT 8987E is the same its supposed to fit, you have other numbers for batch and production date.But it is a programmed chip.as written on other posts.Unless you can find another "same board" donnor, you wont be able to make your board working again, if you dont have the tools/softs and firmware to program it.
Fluke 177 Meter Dead - Page 1
Forum section: electronics / repair

author: Manoj Soorya
author_rank: Newbie
timestamp: September 29, 2018, 09:18:56 am
content: Sir,My Fluke 177 is not display nothing. It suddenly happen. Battery is good.There is a chip name LT511 24351.. any datasheet of this chip? I think the problem with this chip.and any link to purchase a new chip from ebay or some other site?Thanking youManoj Soorya

author: retiredcaps
author_rank: Super Contributor
timestamp: September 29, 2018, 06:50:37 pm
content: Q1) When you turn on the meter to DCV, does it show anything on the lcd? Does it show 0.000 or nothing on the lcd?Q2) Did you try a fresh new battery?Q3) Can you post clear focused pictures of your pcb? both sides please.Q4) If you hookup the 177 to a DC power supply, how much current does it draw?

author: t1d
author_rank: Super Contributor
timestamp: October 01, 2018, 10:22:23 am
content: Happened suddenly? Under what conditions? Did you just blow a fuse?

author: retiredcaps
author_rank: Super Contributor
timestamp: October 02, 2018, 03:03:55 am
content: Quote from: t1d on October 01, 2018, 10:22:23 amThe fuse in Fluke handheld multimeters only protect the current ranges. A bad fuse is likely not the problem here.
Component ID  - Page 1
Forum section: electronics / repair

author: homestea
author_rank: Regular Contributor
timestamp: October 01, 2018, 03:59:52 pm
content: Can anyone help identify these burnt up Diodes? Working on repairing an Agilent handheld spectrum analyzer and cant find the specs for these. Thanks in advance for any help you can provide!

author: homestea
author_rank: Regular Contributor
timestamp: October 01, 2018, 04:18:02 pm
content: Thanks so much!!!
fixing my cheapo soldering station  - Page 1
Forum section: electronics / repair

author: hussamaldean
author_rank: Unknown
timestamp: October 09, 2018, 12:33:36 pm
content: Hi all,I have cheapo soldering station for smd rework. however, after 6 months of usage I've noticed that the temperature is unstable and goes even worse with the time like going up to 800 and stays there for three minutes and the heater is off.this video shows the partial problemhttps://i.imgur.com/LVps6yS.mp4anyway, since I know how to program Arduino, and with extra stuff used I managed to fix itof course the following has been usedMax6675 thermocouple type K signal conditioning ICL298N Motor driver used as switch for switching1602LCD for displayencoder to set the temperaturesince I don't have 3D-printer I couldn't build my own case, so I referred to store and I got myself a box and start what I hate most, labour work but I managed to get it pretty decent thoughthis is the final product.hope you like this small topic with my attempt to fix it.price of the new one is about 60$the fix is about 12$but the results are far superior compared with the original
B&G H3000 CPU. Identify a burnt chip. Help wanted. - Page 1
Forum section: electronics / repair

author: sotos
author_rank: Frequent Contributor
timestamp: September 30, 2018, 01:00:57 pm
content: Please help me identify a burnt chip from a B&G H3000 CPU. From this chip tracing the tracks it goes to the NMEA hardware connector out.Any help will be appreciated.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 30, 2018, 02:25:41 pm
content: Try marine products forums ?Contact, Write, Fax, E-Mail,Call M-F [9.00am-5.00pm Central US (- 6h GMT)] at:Hellas Marine, Inc.Chicago Marine Electronics212 E. Crescent Ave.Elmhurst IL. 60126, USAUSA Phone : +1 (630) 501-1938Email : cme@chicagomarineelectronics.comtech support :http://www.chicagomarineelectronics.com/support.htm
Hantek 1008C 230V on oscilloscope ground - Page 1
Forum section: electronics / repair

author: kr
author_rank: Newbie
timestamp: September 30, 2018, 08:13:57 am
content: Hi,I accidentally shorted 230V to negative lead of my oscilloscope while doing some measurements. My laptop(PCH) and hantek both are dead.... on hantek board i can see that C410 was completely blown away, near L413 is showing ohms instead mH(measured with element tester), I can't find any service manual for this board, maybe someone could measure their C410, L413 and post photo of R15 which seems to be damaged aswell and can't be identified. Might be other damage that i cannot see right away. I'm not very experienced with troubleshooting electronics so any advice is welcome. Sorry for bad english.//Edit : 1R15 is X10 - fixedU3 is ASM11177 - fixed i got 3.3V backStill not recognized usb device, still no diodeOne HC595 looks damaged.Starting to think it's not worth to trace everything.//Edit : 2STM32 propably damaged... will try to read but dunno is it protected or not
replacement for IR 10D-4 and 10D-4R rectifier bridge diodes for power supply - Page 1
Forum section: electronics / repair

author: jaunty
author_rank: Regular Contributor
timestamp: September 28, 2018, 09:47:09 am
content: I have a power supply for a very important project that uses FOUR bridge rectifiers - each comprised of a pair of international rectifier 10D-4 and 10D-4R three leg diode pairs ... does anyone know of a source for NOS versions of these??? I can't find ANY by google ... nor can i find any spec - they are from 1974 ish. I'm ASSUMING i could probably build up replacements from 1N4004 through 1N4007s .... but still ... i have no spec ... can anyone take an educated guess at this?

author: capt bullshot
author_rank: Super Contributor
timestamp: September 28, 2018, 09:52:39 am
content: From your description, these could be dual diodes with common anode or common cathode. One can replace them by single diodes of appropriate ratings.Could you post a picture of the diodes and their environment pleaseIs this a 50/60Hz rectifier or a switch mode power supply? That would make up a significant difference in diode choice.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 28, 2018, 12:31:57 pm
content: You can take bridge rectifiers and use half of it

author: drussell
author_rank: Super Contributor
timestamp: September 28, 2018, 02:21:01 pm
content: Any combination of diodes with appropriate specifications will replace your current diodes, whether it is two duals, four singles or a four-diode bridge package.Also, please stop creating different threads for problems with the same unit. This is unhelpful.

author: jaunty
author_rank: Regular Contributor
timestamp: October 03, 2018, 03:04:58 pm
content: Quote from: capt bullshot on September 28, 2018, 09:52:39 amhi - yes - dual diodes ... they look like thishttps://page.auctions.yahoo.co.jp/jp/auction/p457004569linear power supply. I threw in some 1N4004s and it seems to be holding it together for the moment - i figured the 1A rating on the 1N4004 would be adequate considering A. the main fuse is only 500mA and B. there are four secondaries feeding off that ... each with it's own bridge rectifier

author: jaunty
author_rank: Regular Contributor
timestamp: October 03, 2018, 03:06:52 pm
content: Quote from: drussell on September 28, 2018, 02:21:01 pmok ... i thought it would be MORE helpful to not overcomplicate a thread .. since (technically) it was a completely different issue (even though the same PS) ... and i figured that was also better for people like me who 'mine the archives' looking for specific topics ...
Atten 8586 Repair/Upgrade 907 iron with T12 parts - Page 1
Forum section: electronics / repair

author: ElectronicSailor
author_rank: Newbie
timestamp: August 16, 2018, 06:35:29 am
content: Hi guys. I have one of these Atten 8586 Combo Stations with a clone of the 907 handle.https://www.aliexpress.com/item/2-in-1-Soldering-Station-ATTEN-AT8586-Hot-Air-Gun-Soldering-Iron/624671611.htmlThe 907 iron the atten has, has 7 pins but only 5 wires with one for esd and a stainless steel heating element.https://www.aliexpress.com/item/ATTEN-907-ESD-Soldering-Iron-Handle-Soldering-Station-handle-7-pin-for-AT8586-AT936b/32673518970.htmlMy basic problem is, the heat transfer is kinda bad. The tip sits too lose on the heating element for my taste.Since The t12 tips have a integrated heating element, the heat transfer would be better I assume, so I'm looking if I could somehow convert my hakko to use a T12 iron with tips.I did a lot of reading on that topic, but there are still some things that are not really clear to me, and I hope you can help me there.I found the following parts.A handle for 936 to t12 conversionhttps://www.aliexpress.com/item/T12-Heater-Handle-For-Modification-Hakko-936-Soldering-Station-Iron-DIY/32835896063.htmlSome brackets:https://www.aliexpress.com/item/T12-Handle-Core-Bracket-DIY-Soldering-Station-Kits-Sleep-Wake-Switch-Plug-For-Hakko-936-907/32871990940.htmlhttps://www.aliexpress.com/item/Durable-T12-Iron-Tip-Holder-Pluggable-Handle-Core-Bracket-DIY-Welding-Accessory-for-HAKKO-936-907/32885424034.htmlhttps://www.ebay.de/itm/HAKKO-936-907-to-T12-Handle-Core-Bracket-Fo-616-STC-Soldering-Station-Controller/181953967128?epid=28009609014&hash=item2a5d4d3418:g:O9UAAOSwNphWZP5vI assume I would have to make some kind of frankenstein soldering iron for this to work ^^So would it be enough, using the cable of the old 907 iron with a T12 Shell and one of the above brackets or would I need some kind of special circuit like from the link below to use T12 parts?https://www.eevblog.com/forum/reviews/interesting-936-to-t12-(fx951-integrated-tip)-conversion/I probably also would have to find out if the atten iron has a thermistor or a thermocouple and what the t12 parts uses...My feeling tells me, the parts from above are probably not enough and I'm still missing something, if the conversion is possible at all.Thank you.edit: measured ohm between the two white cables from the heater ~12.5 ohm, and the red and yellow cable ~1.5 ohmSo the heating element is probably a A1323 with thermocouple?

author: attenchina
author_rank: Newbie
timestamp: September 30, 2018, 01:44:30 am
content: ABOIVE , IT IS RESELLER,I FOUND atten official in Chinait ishttp://www.atten.com