hybridfree/eevblog-posts huggingface dataset:
Part identification help need pls. - Page 1
Forum section: electronics / repair

author: Chriss
author_rank: Frequent Contributor
timestamp: April 15, 2019, 09:19:23 am
content: Hi!I have to identify a part on a graphics card.Check the picture for the part I search for.Is it a MOSFET or a diode?I found some sources on the internet they talk about like if it is a mosfet but when I check it with dmm it reakt like a diode.There are also several same parts on the pcb and I compared the readings with each other but they are the same.It is impossible does all the same parts are bad on the pcb.If I check for continuity between the middle pin and the right pin (D and S) it react as a diode.But no reaction when I measure between all the pins and the left pin.Any idea what part this could be?Thanks.

author: kosomsk
author_rank: Regular Contributor
timestamp: April 15, 2019, 10:52:23 am
content: 14N03 on semiFull name NTD14N03Rhttp://www.onsemi.com/pub/Collateral/NTD14N03R-D.PDF

author: testpoint1
author_rank: Frequent Contributor
timestamp: April 15, 2019, 11:12:13 am
content: Quote from: Chriss on April 15, 2019, 09:19:23 amT14N03, MOS FET, TO-252

author: Chriss
author_rank: Frequent Contributor
timestamp: April 15, 2019, 08:22:10 pm
content: testpoint1:Thanks for the info.Do you maybe have a datasheet for it?The datasheet from this sitehttp://www.onsemi.com/pub/Collateral/NTD14N03R-D.PDFis incorrect.Based of the pinout on that link the middle pin is the D and the right pin is the S.Between these two pins I can read a diode type of reading. If I put the positive probe of my dmm on the Dand the negative probe to the S I got a reading like 1998mV. If I interchange the probes I got a reading of 600mV.And I can't brake the conductive state of that two pins as it should be done on a regular MOSFET.I know, there is a protective diode between the S and D but why can I not make conductiv the D and S and after that I should could break the conductive state between the S and D.I mean, I should power on and off the MOSFET with my dmm.I also don't assume does 5 or 6 of these MOSFETS are actually all killed on the graphics card, but they allreact the same way.

author: bob91343
author_rank: Super Contributor
timestamp: April 17, 2019, 04:21:57 pm
content: For this kind of identity problem, I would use one of those cheap Chinese 'magic' devices that cost around $30 complete and are capable of identifying many kinds of parts. They were invented by Europeans but China has produced them at very affordable prices. Google MEGA328 I think; get them from ebay.They measure nearly any part, R, C, L, diode, transistor (many types) and so on. They also identify lead configuration. I have found mine nearly invaluable. Not that the result is always accurate but for what it does I don't mind. Once I establish identity I can use my other test gear for better readings.

author: Chriss
author_rank: Frequent Contributor
timestamp: April 17, 2019, 07:27:21 pm
content: Yea!I ordered one of these tester from aliexpress some days ago... anyway thanks for the suggestion.
Keithley 2410 Fan Replacement - Page 1
Forum section: electronics / repair

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: April 16, 2019, 08:14:31 pm
content: so, finally, i couldn't stand the whining fan on my Keithley 2410 any longer. Being an early version, it still had the simplistic bottom plate drill-out pattern as opposed to the later-version circular venting slots for the fan. so i hacked an orifice into the bottom with the exact diameter of the fan replacement, a NOCTUA NF-A6x25/5V PWM.The PWM feature is not used here, but i didn't care, as i was just looking for a quiet fan that would also deliver enough static pressure besides the required airflow. although the NOCTUA is barely noticeable when operating "open frame", the noise reduction after been built into the SMU's cabinet isn't quite as impressive, but still very well worth the effort.To give you an impression of the achieved noise reduction in comparison to the original fan, have a look at the acoustic measurement done with my phone and "Audio Tool", the phone being placed on the workbench 10 cm away from the SMU: grey curve is original fan, green curve is NF-A6X-25.
ICOM-R7100 - Page 1
Forum section: electronics / repair

author: Radiosonde
author_rank: Contributor
timestamp: April 16, 2019, 08:13:28 pm
content: HelloI received (yeah...) a IC-R7100 receiver a few months ago from a ham radio friend for repair.It was possible to turn the receiver on and hear some noise but otherwise it was totaly deaf, so I started inserting a signal and tracing it back, I stopped at the 2. Mixer Unit which seemed to be broken. I also inserted signals in the 10.7 Mhz and the 455khz IF, everything ok, no problems whatsoever.My plan was to build a new mixer module around a AD831 and hack it into the receiver, then re adjust it.Repair isnt possible because the MIX2 IC is the only ASIC in the whole receiver, it is such a PCB-Chip weird thingie which I cant replace or repair.Everything looked nice and I started to build the mixer PCB, I "simulated" the same conditions as in the receiver on my bench with signal generators to be sure it will work, it will, even if I am out of the specified 500 Mhz the mixer works fine and outputs a usable IF.Sadly now nothing works, the receiver greeted me with various problems when I opened it today to check some values:1. It doesnt do noise anymore, only a very silent hum in the speaker2. The demodulator stages dont work, I havent done something with them in the last two months3. The 1. local oscillator doesnt "track" anymore, it should follow the typed in frequency in a specific way to keep the IF on a constant value, nothing, it is about 100 Mhz of and only chages value slightly, I tried it with the adjustement procedure but here I only can tweek in khz ranges at best.What could be the reason for getting worse and worse?I am very frustrated now, it is like one step forward and five back?Could this be affected by bad electrolytics?The unit was in storage for 10 years as defective.Like I said it is annoying because now the design of the new mixer and invested time is wasted, I am sceptic that I can an want to fix all these problems that were not here in the beginning.Thank you for support
Simpson 606 chart recorder - Page 1
Forum section: electronics / repair

author: bob91343
author_rank: Super Contributor
timestamp: April 15, 2019, 05:31:57 am
content: I have one of these with a broken and stripped gear. It's a nice unit and I'd like to get it going.It's made by Goerz in Europe and has many nice ranges and chart speeds.The gear in question is between the pen drive motor shaft and a drum gear that moves a dial string attached to the pen.I can provide pictures if it would help. The whole gear is maybe a half inch in diameter or less and the same height, with a shaft hole of around .09 inch or less. There are two gears on the same part, one about 50 teeth meshing with the motor and the other maybe 18 teeth meshing with the drum.Basically I want to replace the gear but have no idea where to get one. I have ordered a gear assortment from China. Maybe I can cobble up a replacement.A search online yields no help on contacting the manufacturer. Simpson people in Wisconsin never heard of the unit.

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 15, 2019, 01:02:36 pm
content: If Simpson does not recognize it then it sounds like something they stuck their label on at some point in well past history. I would post a picture so that someone might recognize it under a different manufacture's name, if that ever happened.

author: bob91343
author_rank: Super Contributor
timestamp: April 15, 2019, 04:30:03 pm
content: Rather than post a picture, one can look at several of these units on ebay. It's not a large unit, and yes it was rebranded. Or, I think, a special import with the proper logos etc. to make it appear as though it was a genuine Simpson product. Which it was not.I have some pics of the damaged part and the interior where it is supposed to go, if that would help.I do find it odd that such a nice unit is so rare. Perhaps it was overpriced or poorly marketed.The famous model 260 has to be the most popular VOM in history, in spite of the fact that there were better units with more logical interface. Notably the Triplett 630, that had two main drawbacks, namely its larger size and use of a rare 30 Volt battery for Ohms. I have one of each but seldom use them.

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 16, 2019, 11:25:33 am
content: Quote from: bob91343 on April 15, 2019, 04:30:03 pmBest of luck with you search.

author: bob91343
author_rank: Super Contributor
timestamp: April 16, 2019, 05:22:46 pm
content: Thank you. I have ordered an inexpensive batch of assorted plastic gears from China. When they arrive in a month or so I will see if any are close enough to do the job. I'm sure I will have to cement two gears together but that's the easy part.I just wish the company were accessible to at least ask them if they have such a part somewhere.
Resistor weird color code - Page 1
Forum section: electronics / repair

author: ramiro
author_rank: Newbie
timestamp: April 15, 2019, 12:27:17 pm
content: HelloI am trying to repair a Power Supply , and beside a blown chip it has an resistor that i meassure with 2 mohm in the circuit what doesn't seem right for me but i can't read it because it has 2 times gold in the middle and gold shouldn't be in the 3. band.The color code is red red gold gold green .I also attached a picture of the resistorThanksRamiro

author: StillTrying
author_rank: Super Contributor
timestamp: April 15, 2019, 01:08:15 pm
content: 2R2http://kiloohm.info/resistor-4/red-red-gold-goldDon't worry about the green.

author: Shock
author_rank: Super Contributor
timestamp: April 15, 2019, 01:19:23 pm
content: Here is a chart that may help.

author: ramiro
author_rank: Newbie
timestamp: April 15, 2019, 02:28:11 pm
content: Thanks 2.2 was right the psu is working fine now , just a little confusing that you have to ignore a band.
Agilen/Keysight U1273A Dim display... - Page 1
Forum section: electronics / repair

author: Lockon Stratos
author_rank: Regular Contributor
timestamp: April 12, 2019, 04:13:56 pm
content: Hi all.So i have a u1273a which served me very well and im loving its oled display, but unfortunately it became so dim that its practically impossible to read... Is there a way to salvage it or get a replacement display?Thanks in advance.

author: rsjsouza
author_rank: Super Contributor
timestamp: April 12, 2019, 08:04:49 pm
content: There is a discussion with suggestions at:https://www.eevblog.com/forum/testgear/replacing-oled-screen-on-an-agilent-u1253a-multimeter/Unfortunately, sourcing the display is not very trivial.

author: Lockon Stratos
author_rank: Regular Contributor
timestamp: April 15, 2019, 12:03:53 pm
content: Quote from: rsjsouza on April 12, 2019, 08:04:49 pmThanks, digging through it ATM but it doesnt look pretty...
Repair Fluke 5500A Error 104 - Page 1
Forum section: electronics / repair

author: Regiano
author_rank: Newbie
timestamp: April 13, 2019, 04:32:49 pm
content: I had a problem and entered 220V at the input of my fluke 5500A Calibrator , now it is turning on ERROR 104 trip relay, can someone help me with this defect.thanks

author: dacman
author_rank: Frequent Contributor
timestamp: April 15, 2019, 02:31:05 am
content: I would suggest sending it to Fluke for repair. I know someone that zapped a 5520A and Fluke replaced a plethora of items in it. (The 5502A and 5522A have input protection. The 5500A and 5520A do not.)

author: coromonadalix
author_rank: Super Contributor
timestamp: April 15, 2019, 03:01:07 am
content: services manuals with schematics, surely you have them already ??https://archive.org/details/FLUKE5500ASERVICEMANUALWITHSCHEMATICS/page/n269you can choose different format, the pdf is around 12 megshttps://www.dropbox.com/s/48p5qlqob1f4ysj/FLUKE%205500A%20SERVICE%20MANUAL%20WITH%20SCHEMATICS.pdf?dl=0the input sections are at section 6-12 page 263 ...do you have something burned busted cracked to help pinpoint a section ??
Outdoor Unit Inverter PCB for Split Type Air conditioner - Page 1
Forum section: electronics / repair

author: D3K
author_rank: Newbie
timestamp: April 12, 2019, 07:00:30 pm
content: Dear friends,I am trying to repair some air conditioner outdoor unit boards to supplement by income as I am a student.Where I live we have a lot of problems with inverter PCBs. I've read that if you test without a compressor the three-phase output should be present for a few seconds before being switched off by the controller.My question is this; is it possible to test the inverter board without the indoor unit?There are some pins denoted TEST/SS pins but could not get a useful output when checking the U,V,W outputs with a differential probe.Any help is greatly appreciated.

author: Gregg
author_rank: Super Contributor
timestamp: April 12, 2019, 10:58:09 pm
content: The quick answer to your direct question: yes, it is possible; many things are possible with enough time and money.The big question is, “is it practical for a student to attempt making more than they spend on test equipment and simulation hardware?”If you have a whole bunch of the same dead cards and access to the controller card, it may work out for you if count the learning experience as value and not just the pittance you may be able to charge for “rebuilt” boards.Then there is the liability factor, safety concerns etc.I’m not trying to discourage as much as enlighten you to the reality of your endeavor.

author: soldar
author_rank: Super Contributor
timestamp: April 14, 2019, 10:23:03 am
content: The compressor is not in the indoor unit but in the outdoor unit.
Johnson Controls 8 NET 16 power supply repair - help needed - Page 1
Forum section: electronics / repair

author: E Schnieder
author_rank: Newbie
timestamp: April 19, 2019, 10:03:00 am
content: Hello,I've bought a Johnson Controls power supply to mount in a 19"-Rack for Eurocard-type PCBs. I tried to switch it on outside of a case, which should work, but the only thing it did was creating some sparks and blowing the fuse. Typical magic smoke.Taking it apart I found out that some SMD components are burned beyond recognition.Does anyone have a similar power supply or even schematics of this one to help me fix it?
Panel Visonic alguien que lo trabaje o lo conozca - Page 1
Forum section: electronics / repair

author: sergio06
author_rank: Newbie
timestamp: April 12, 2019, 03:36:14 pm
content: Hola, tengo una alarma vieja es una Visonic Powermax Espress se bloqueo me sale P1: N2: N3 queria saber si alguien sabe como desbloquearla..Saludos cordiales

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 13, 2019, 12:31:36 pm
content: Holà. Ingles aqui por favor...Soft ResetA Soft-Reset will not reset the master installer code or user code. A soft-reset will reset the zone programming etc. All devices will be deleted.To perform the Reset:Enter Installer Mode.Scroll through the menus until you see FACTORY DEFLT, Press <OK>.Display will show <OK> to restore, Press <OK>.Display will show ENTER CODE, enter the master installer code.Display will show PLEASE WAIT... for a short time, after which the factory defaults will have loaded.The display will revert to FACTORY DEFLT.Hard-ResetA Hard-Reset will reset the Master installer code to 9999 and the user code to 1111.To perform a hard-reset on the Powermax Pro control panel;Remove the mains power to the control panel.Open the control panel and disconnect the battery.Identify the 3 pins marked DEFFit a jumper across the D and E pinsApply battery power to the panel for approximately 10 seconds.Remove battery power from the panel.Remove the jumper from the D and E pins.Re-connect the battery.Close the panel and apply mains power.
HP 3585B Display Replacement - Page 1
Forum section: electronics / repair

author: Cloud
author_rank: Regular Contributor
timestamp: April 12, 2019, 08:49:54 am
content: The display in our old trusty 3585B is slowly fading away and we aren't ready to say goodbye to it. What options do we have to save the patient? I was looking at CRT tubes on ebay but they are mostly in unknown condition. Is there any way to do LCD conversion as on some of Tektronix scopes or maybe a good way to stream data via GPIB?

author: drknob
author_rank: Contributor
timestamp: April 12, 2019, 01:19:59 pm
content: https://www.sphere.bc.ca/test/hp-crts.html

author: dacman
author_rank: Frequent Contributor
timestamp: April 12, 2019, 09:12:30 pm
content: It has rear panel X, Y, Z outputs that can be used to duplicate the display on an oscilloscope. With a little engineering, the CRT can be replaced with an LCD.
Converting a cheap Yihua/WEP 852D+ to be safe - Page 1
Forum section: electronics / repair

author: ullbeking
author_rank: Newbie
timestamp: April 09, 2019, 01:57:13 am
content: Hi all,I bought a Yihua/WEP 852D+ from Ebay for cheap because it was great value and recommended. After I received it I also heard a lot of other things and saw some videos questioning its safety, grounding, etc.I'm re-acquainting myself with electronics after a very, very long hiatus.Does anybody know of a guide that shows how to "repair" this SMD iron plus hot air compressor so that it is safe? Thanks!!Kind regards,ubk

author: ttelectronic
author_rank: Regular Contributor
timestamp: April 09, 2019, 02:30:58 am
content: I think the mistakes in wiring vary, me and a relative both got one and I think both the switch and fuse on one were on the neutral side and the other the switch was on the hot side, but the fuse was on the neutral. If you do mess with the internal wiring, make sure you are right in what you do to fix it, and generally the ground should be crimped, not soldered to the wire, which I think they usually are.

author: ullbeking
author_rank: Newbie
timestamp: April 10, 2019, 06:04:30 pm
content: Quote from: ttelectronic on April 09, 2019, 02:30:58 amThanks for the heads up. Of course, I'm not going to mess with the insides of a soldering iron unless I know what I'm doing.However, ensuring that it is grounded properly is an important special case. Why does ground need to be crimped instead of soldered?Also, are you saying that in these cheap copies of legitimate soldering irons, the ground is often soldered?

author: ullbeking
author_rank: Newbie
timestamp: April 12, 2019, 10:17:17 am
content: Quote from: ttelectronic on April 09, 2019, 02:30:58 amNevermind the question I asked above, but thank you for mentioning this. I searched and found the answer to this myself. It all makes perfect sense. For example:https://www.eevblog.com/forum/beginners/earthing-why-crimp-and-not-solder/
Agilent E3646A Repair - Rotary encoder and N80C51BH 3440-88804 Failures - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: April 12, 2019, 03:32:52 am
content: Hi All,I thought I would post this here, it is my repair of an Agilent (Keysight) E3646A dual output power supply.It started off with a bad encoder, but then I slipped with a probe and blew U7, so then I had to replace the microprocessor too !I have this unit for sale on TM if you are in NZ and looking for one.
Peaktech 1885 / BK Precision 1697 repair [schematic needed] - Page 1
Forum section: electronics / repair

author: Noy
author_rank: Frequent Contributor
timestamp: April 11, 2019, 08:14:54 pm
content: Hi, i got a two Peaktech 1885 with some issues.They are the same like BK Precision 1697.Does anybody have some schematics for this or the other "Family" Models (BK 1696, 1698 / Peaktech 1890)?The first Peaktech has no output anymore (no voltage at the bananaplugs, i think the output "switch" (thought is would be an relais but looks like a transistor) is broken).The second is constantly 3V above the programmed output voltage. But it is not possible to calibrate it with the internal Pots mentioned in the Manual. I think a reference is broken...It would be nice if somebody has the schematic or maybe repaired already one or both of the mentioned issues...?
Hameg HMO3524 channel 1 repair - Page 1
Forum section: electronics / repair

author: Noy
author_rank: Frequent Contributor
timestamp: December 12, 2018, 11:03:55 pm
content: Hi guys,i got a HMO3524 with 3 working and 1 non working channel.Channel 2-4 is ok. Channel 1 is clipping anywhere at the max (not shown on screen), it is independent of DC/AC input select and 50 Ohm input selection also.Only if i put it into GND selection its shown on screen. I opened it already and I try to check the difference between channel 2 and channel 1.Until now i found out that it is overdriven. I will post pictures and more details tomorrow. But has anybody any suggestions, what it could be?

author: Noy
author_rank: Frequent Contributor
timestamp: December 16, 2018, 12:06:18 am
content: OK now some new information...I took a thermal image from channel 1 and channel 2 (see attached).Difference is currently the PMBFJ620 JFET himself the hot (SC70) package is ok. But anything put the channel into clipping, it's totally oversteered.Here are some pics:

author: Noy
author_rank: Frequent Contributor
timestamp: April 11, 2019, 08:04:07 pm
content: Replaced the Opamps and its back working...Only the small part (dark grey) left to the SOT-23-3 beside the blue pot mold a bit as i touched it accidently with my solderiron...The channel works and it looks like everything is ok but what could the part be? It mold directly like it would be out of plastic...
Old panasonic inverter microwave - inverter repair - Page 1
Forum section: electronics / repair

author: ExtraThiccBoi
author_rank: Contributor
timestamp: April 11, 2019, 07:47:24 pm
content: Hi,my microwave just stopped working, i took it apart and noticed a blown ceramic 3kV capacitor on the inverter HV side, it was also sparking in that spot.I replaced it and when i turned on the heating, the new cap blew again and split in half.I do not see any other damaged components. I checked the high voltage rectifier and the diodes have both Vdrop of around 2.8V. One of the diodes seemed to have a cold connection. Could that be causing the HV cap to blow?The transformer reads dead short which seems kind of strange to me, is it supposed to be like that?My other idea is that the logic does not give correct PWM causing the inverter to put out too much power or something.Anyone got any idea what to do? I would be like to repair atleast the inverter and giving it my own logic (from an arduino or whatever).Thanks!
Fluke D804/8024b Touch-Hold switch - Page 1
Forum section: electronics / repair

author: ogdento
author_rank: Regular Contributor
timestamp: April 10, 2019, 12:28:50 am
content: Hi,I recently acquired a nice looking D804 (I think it's the same as the 8024b) and upon cracking it open it seems the Touch Hold button is shattered.There was a piece rattling around inside, but the two bits together don't make up the full part.The part number is 607333... has anybody got a spare kicking around? I'd buy it or at least love to see some photos so I can try to fashion a replacement... it looks like there should be two "fingers" that fit around the actual pushbutton, but I don't know exactly what it's supposed to look like.Thanks,Tom

author: GLouie
author_rank: Regular Contributor
timestamp: April 10, 2019, 11:18:03 pm
content: You mean the peak hold switch, right?Give me a day to take mine apart and photograph the part.

author: GLouie
author_rank: Regular Contributor
timestamp: April 11, 2019, 12:11:02 am
content: You seem to be missing some parts.Some pics attached (2 batches):

author: GLouie
author_rank: Regular Contributor
timestamp: April 11, 2019, 12:12:25 am
content: More pics:

author: ogdento
author_rank: Regular Contributor
timestamp: April 11, 2019, 05:13:09 am
content: Wow, GLouie thank you so much... it seems I am indeed missing quite a bit of it! Those pictures are super helpful, half of mine is just gone.I'll take a crack at a 3d model and see what I can come up with.
Rohde & Schwarz CMS-50 with Digital 840.2301 info needed - Page 1
Forum section: electronics / repair

author: pa4mic
author_rank: Newbie
timestamp: April 14, 2019, 08:44:51 am
content: Hello all,I have an Rohde & Schwarz CMS-50 unit and i found an digital unit in it that is not described in any service manual i have found till today, its 840.2301. The unit is different from the digital 840.5400.02, my version has 4 eproms and the older ones 5 eproms (as far as we know now the 5 eproms version goes to firmware 5.x and the 4 starts from 6.x to 6.06 known till now)If there are people that can help with any information, documents or maybe software versions please let me know.Michael
GW instek PSH 3630 repair - No voltage output - Page 1
Forum section: electronics / repair

author: ginSeven
author_rank: Newbie
timestamp: April 10, 2019, 05:23:19 am
content: Hi,I am currently repairing a PSH 3630 1KW programmable power supply. It boots up fine, and all the controls work. The only issue is when I will trigger to enable the output, the output is 0. I have tried applying a voltage to the sense pins behind, and it does show up on the display. Any ideas on where to start?Device history:There are 3 power supply modules that are connected in parallel, one of them was blown, and found out it was the fuse. I removed and disconnected that module until I get a replacement part for it. Currently there are only 2 modules working. There is a main controller board (display and controls are connected here), and some slave controller boards (interconnected by cables). Tried swapping out modules and controller boards, but it doesn't work as well.Thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 10, 2019, 10:22:55 am
content: maybe something like this may helpI saw a video repair months ago, dont recal where i saw ithttp://thesignalpath.com/blogs/2018/11/23/teardown-repair-of-an-gw-instek-psw80-40-5-1080w-multi-range-programmable-power-supply/
[Fixed] Don't laugh at me, but in 2019 I need to fix a VHS Player - Page 1
Forum section: electronics / repair

author: Zucca
author_rank: Unknown
timestamp: April 08, 2019, 09:45:33 pm
content: Short Story: my father broke his beloved VHS Player JVC HR-S8600: it always spits the cassette out.I found these two mechanical parts that were rattling free inside the device:I have no clue where they were mounted!It looks like they were joint together, like this:Maybe some of you were working on those units and remember what to do or were the hell those parts falls of from this device:This above is the top part, I have the feeling those were mounted on the bottom part. Yes I hate mechanical problems in electronics devices.Service Manual:https://www.dropbox.com/s/gjqm1sdyjksuntr/jvc_hr_s8600_s9600.pdf?dl=0Other Pictures:https://www.dropbox.com/sh/7moqrfjf6e19e83/AABqthYODrzixbzo_PyyDzAma?dl=0Thanks in advance!

author: Mickster
author_rank: Contributor
timestamp: April 08, 2019, 10:32:57 pm
content: Wild Arsed Guess...Can you see a photo-interrupter somewhere around the cassette loading mechanism, which doesn't have anything to erm interrupt it?

author: Psi
author_rank: Super Contributor
timestamp: April 08, 2019, 10:45:34 pm
content: I had a quick look and couldn't see anything obvious.I would focus your investigation in this area.It's likely broken due to the force of inserting a tape and this is where those sort of parts are.I don't think you have much choice but to first remove the entire tape loading module from the VCR so that you can see it properly on all sides.Take a video of everything you do to when removing it. Then you will have a reference to check when reassembling if you're not sure where something goes or what connector goes where.

author: zed65
author_rank: Contributor
timestamp: April 08, 2019, 10:55:58 pm
content: Maybe ontop of this thing

author: tsman
author_rank: Frequent Contributor
timestamp: April 08, 2019, 11:01:59 pm
content: It is mechanism part 10 TENSION STUD BASE and 11 TENSION STUD. See attached. I've included a very fuzzy photo of another JVC VCR mechanism which you can see the plastic part.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 08, 2019, 11:04:13 pm
content: part no 10 in the section 5.3 mechanism assembly M4 ??tsman got me while writing this loll

author: Psi
author_rank: Super Contributor
timestamp: April 08, 2019, 11:07:05 pm
content: Nice spotting!Quote from: tsman on April 08, 2019, 11:01:59 pm

author: Zucca
author_rank: Unknown
timestamp: April 09, 2019, 09:58:04 pm
content: Little Bastard!After some tiny drops of grease on some mechanical parts, some general cleaning with compress air and IPA everything works like expected.tsmanandcoromonadalixPM me if you are coming to Munich, thiswill be yours for free!Thanks on the others too, for them just 0,5L for free.
Help.. can someone identify this IC please? - Page 1
Forum section: electronics / repair

author: cozza
author_rank: Regular Contributor
timestamp: April 08, 2019, 10:03:13 pm
content: Hi, I have had to replace a damaged USB port on this LED light controller. Unfortunately while de-soldering the socket, I accidentally flicked the edge of the 6 pin IC with my soldering iron tip and chipped the package. I don't have a schematic for the unit as it's not available.I'd like to replace the chip for reliability, it is still working but is probably no longer moisture proof.The only marking it is ".F" , it appears to be a signal conditioner or buffer for the two data lines. It's a USB 2 (or possibly USB1) connection.If anyone recognises this 6 pin device, please let me know.Thanks!

author: wraper
author_rank: Unknown
timestamp: April 08, 2019, 10:07:45 pm
content: Quote from: cozza on April 08, 2019, 10:03:13 pmIt's not like plastic packages have moisture proof outer layer. They do absorb some moisture but chipped corner basically has zero impact on that. Part should be some sort of ESD protection device.

author: cozza
author_rank: Regular Contributor
timestamp: April 08, 2019, 10:36:43 pm
content: ESD protection seems quite likely as the signal connections measure less than 1 ohm in to out across the device.I forgot to mention, this is a fairly high end unit and I'd be happier knowing it was going back into the field in a reliable conditionThe package is compromised more than the photos show. I had trouble getting focus on the damaged area.

author: stefanh
author_rank: Contributor
timestamp: April 08, 2019, 10:56:19 pm
content: This could be an ST USBLC6-2P6 which have a device marking of "F" according to the datasheet.https://www.st.com/content/ccc/resource/technical/document/datasheet/06/1d/48/9c/6c/20/4a/b2/CD00050750.pdf/files/CD00050750.pdf/jcr:content/translations/en.CD00050750.pdf

author: coromonadalix
author_rank: Super Contributor
timestamp: April 09, 2019, 12:15:12 am
content: its an usb port ? if you check the 2 center pins in ohms to ground, what values do you have

author: cozza
author_rank: Regular Contributor
timestamp: April 09, 2019, 12:40:35 am
content: Thanks Stefanh, from the datasheet, marking, and pinout measured on the board, I'm pretty sure you've found the answer!Much appreciated, I will order one in and replace it!

author: stefanh
author_rank: Contributor
timestamp: April 09, 2019, 03:39:34 am
content: No worries - I was pretty sure it was a USB ESD Device, and I often use the SOT23-6 part. Was quick and easy to check the datasheet I had on hand.
RED SCREEN Oscilloscope Tektronix TBS 1102B 100Mhz/2Gsps  - Page 1
Forum section: electronics / repair

author: MARSHALBSB
author_rank: Contributor
timestamp: April 04, 2019, 05:06:06 pm
content: Evening everyone,Today while turn my oscilloscope on, I've noted that where use to be BLACK is now RED...I tried to adjust the bright intensity and it works...for 30 seconds...then it turns RED again... Everything, but the screen, seems to work fine. That's probably a LCD problem, yet, just want to share and know what you guys think about it.

author: Chris56000
author_rank: Frequent Contributor
timestamp: April 05, 2019, 04:41:30 pm
content: Hi!The display and waveform is quite usable according to the picture you've provided for us, and certainly doesn't look like a physical fault to me – I'd be thinking about a display or setup configuration issue for a fault like that!Have a read of the user manual for the 'scope and see if there's a setting to adjust the display's colour pallette, and if there's not an obvious display colour setting that appears to match the display you're getting, the next thing to try is a Factory Reset of the whole scope!Chris Williams

author: stj
author_rank: Super Contributor
timestamp: April 06, 2019, 11:49:30 am
content: interesting.it's not a stuck signal in the red datapath or the blue would look purple.maybe the firmware is corrupt - can you re-flash it?

author: MARSHALBSB
author_rank: Contributor
timestamp: April 08, 2019, 04:30:55 pm
content: Thanks for your reply...Well, at the time you were completely right...however, after that, things get wierd, look at the picturehttps://drive.google.com/open?id=1k4kt_xh5ZCS8kKKwtbcuY_tF1qf0YiFwthis was few minutes after my firs post.After the weekend without touch it ... It's working just fine, no RED sign!

author: MARSHALBSB
author_rank: Contributor
timestamp: April 08, 2019, 04:41:56 pm
content: Thank u for reply,I Could never update the firmware. I can see the file in the flash drive, I choose update, but nothing happens... so I forget about it...But look at the GIF I made just few minutes after my first post:https://drive.google.com/open?id=1k4kt_xh5ZCS8kKKwtbcuY_tF1qf0YiFw
Need a Keithley 2000 Current Input Fuse holder (2001-312D)  - Page 1
Forum section: electronics / repair

author: essele
author_rank: Frequent Contributor
timestamp: April 08, 2019, 02:32:03 pm
content: Hi,I've got a Keithley 2000 with a missing fuse holder for the current input (the white twist in bit), I believe the part number is 2001-312D.I've had a quote from SJ Electronics in the UK (via a Keithley request) but they are quoting £18 + carriage + VAT, which brings the price close to £30 which is absolutely mad (not to mention a potential 6 week lead time, but they can't confirm this.)I don't suppose there is anyone here with one they could sell? Or can anyone point me at another source? (I'm assuming this is a standard part just resold by Keithley??)Thanks,Lee.
Is a Polyester capacitor a good replacement for a Paper Capacitor? - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: April 07, 2019, 05:32:36 am
content: I got to replace a vintage cap that goes into the rectification block of a vintage computer power supply.I can source the KEMET Paper Capacitor 470nF 275V ac ±20% Tolerance P409 Through Hole +85°Chttps://au.rs-online.com/web/p/products/8788032/Would be smarter to get something more "modern"? Like a 470nF Polyester Capacitor PET 250V ac ±10%https://au.rs-online.com/web/p/polyester-film-capacitors/6225069/

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 07, 2019, 06:24:21 am
content: Where is it, across-the-line? You may want an MKT or MKP style X2 rated capacitor. If it's part of a resonant circuit, you may need better performance (polypropylene, rated for whatever current). Otherwise, probably fine and generic, yeah.Tim

author: gkmaia
author_rank: Frequent Contributor
timestamp: April 07, 2019, 08:44:52 am
content: It the C38 bellow.Note the schematic has it as 0.1uf, while the one I removed had 0.470uf. May have been a different revision, but the wiring is similar.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 07, 2019, 09:14:55 am
content: It is a filter cap directly acorss the line. So it must be X1 or X2 class rated. These can be polyester..470 µF would be rather large, possibly even a little unsafe (may get a slight shock touching the plug just removed from the mains). Something like .22 µF should be OK too.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 07, 2019, 07:22:23 pm
content: I'd replace it with same value. It may not be a hazard due to the circuit (at a glance, no idea), and it's a low risk anyway (but it is indeed a thing, and can be quite surprising). MKT or MKP, X1/X2 rated.Tim

author: sergioag
author_rank: Unknown
timestamp: April 07, 2019, 07:34:17 pm
content: Quote from: Kleinstein on April 07, 2019, 09:14:55 amThat's correct. Also, C37 and C38 should be class Y because they connect to ground. Since you're already there, it pays to be careful and make the thing safer.
Submersible pump wires identification - Page 1
Forum section: electronics / repair

author: Gassan
author_rank: Contributor
timestamp: April 09, 2019, 03:11:44 pm
content: Hi All,I got a three phase submersible pump that I have to test by putting it into the mains. I'm afraid to test it because I'm not really sure whether it's a three phase or a single phase motor.There are six leads. The internal connections are not visible because they are within the enclosure. I don't want to disassemble it just to see the connections as doing so might lead to risk of water leakage in the future.Three of those leads are interconnected. They have continuity and there are around 3.5 ohms between each of the leads. The colors of the these wires are red, white and black.The rest of the three leads don't have any connection between each other. One of them, a green wire, for sure is the earth. It has continuity with the body of the pump.The remaining two leads are white in color. As mentioned, they don't have continuity with each other and any of the other wires as well. This is what made me worry. I couldn't figure out what could be the purpose of these wires. Could it be a switch connection? Could it be for some kind of motor control? I don't know.Since the resistance between each of the interconnected leads are about the same, I guess they are coming from three coils of an induction motor. If the motor is single phase capacitor start, induction runtype, then I expect the resistance between the leads to have different values.That's as far as I can describe my problem. I took two photos of the actual thing but couldn't attach them because the file size was too large.Hope someone would pop up with a brilliant solution.

author: amyk
author_rank: Super Contributor
timestamp: April 10, 2019, 01:41:14 am
content: More information about the make/model of the pump itself?You can resize the photos and upload them.

author: DTJ
author_rank: Super Contributor
timestamp: April 10, 2019, 03:50:30 am
content: Quote from: Gassan on April 09, 2019, 03:11:44 pmJust a guess - perhaps the two white wires go to a pressure switch or other flow sensing switch (electrodes??) to enable prevention of dry running of the pump.

author: Gassan
author_rank: Contributor
timestamp: April 10, 2019, 07:27:44 am
content: Thanks.I've talked to someone and he also came to a similar conclusion. Hr said that it should be a thermal switch which would help to prevent the motor from overheating.

author: Gassan
author_rank: Contributor
timestamp: April 10, 2019, 07:31:48 am
content: The pump is very old. I don't have any of its documents. The name plate of the motor also couldn't be found.

author: beanflying
author_rank: Super Contributor
timestamp: April 10, 2019, 07:58:35 am
content: Post up a photo. Industrial pumps was my 'real job' when I had one I might be able to ID what it is.Generally all wiring and control of 3 phase submersibles was above ground and in a cabinet. To that end the six wires will likely be used as part of a Star Delta Starter.
Identifying inductors and testing link switch for condenser dryer pcb. - Page 1
Forum section: electronics / repair

author: Aglovale
author_rank: Newbie
timestamp: April 06, 2019, 07:21:03 pm
content: Hi all. I am trying to repair my condenser dryer -It won't power on- and I need some help if possible. I have been testing caps, diodes and relays without any faults found as of yet. However, while I was testing inductors I noticed odd readings from 3 inductors in particular. According to the colour bands on 3 inductors in picture 1, (only 2 are in picture 1 as the other was de-soldered for testing. however, the de-soldered one is identical to the blue circled inductor - even in readings) the ohms seems to be way off. According to Digi-key web site, the blue circled inductor (Yellow, violet, red and silver band) should be 4700uf and I have a reading of approx 17ohms. The red circled inductor (brown, black, black and silver band) should be 10uf and I'm getting a reading of approx 0.6ohms; all 3 inductors are approx 10x4 mm in size.I found it strange that all these inductors were faulty. However, after some research it seems that the link switch (Picture 2, circled in purple) commonly fails on these boards and can damage resistors (maybe also inductors?) in in the process - from what I have read. The other option of course is that I'm reading the bands incorrectly.Can someone help me identify the resistors and maybe tell me if there is anyway I can test if the link switch is working correctly (as I am not familiar with them).Thank you.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 06, 2019, 07:48:13 pm
content: they are inductances not resistors, and the hint is L2 and L3 on the pc boardInductor Colour Codeshttp://www.learnabout-electronics.org/ac_theory/inductors04.php

author: Aglovale
author_rank: Newbie
timestamp: April 06, 2019, 07:58:02 pm
content: Quote from: coromonadalix on April 06, 2019, 07:48:13 pmThank you so much, I am fairly new to electronics - as my ignorance indicates - I've edited title and description to reflect on your information.

author: Aglovale
author_rank: Newbie
timestamp: April 06, 2019, 08:30:02 pm
content: Ho do I test inductors ?

author: coromonadalix
author_rank: Super Contributor
timestamp: April 06, 2019, 09:02:16 pm
content: Well the cheap way is : to test them as a short, if they read something in ohms they may be good since you dont have "infinite / open" valueThe official way is to test them with an lcr meter
Hp34401a resets itself in 2 seconds cycle. - Page 1
Forum section: electronics / repair

author: henas
author_rank: Contributor
timestamp: April 05, 2019, 06:03:33 am
content: I hope someone can push me in the right direction.Ebay purchased Hp34401a after switching on lit all the segments followed by displaying GPIB address and shortly after resets itself. This can go in 2 second cycle forever. There is no "Error" message segment lit on the display.This unit has single chip display but as far as I can see it works fine and is communicating with main CPU. If I press any front panel button quickly enough after GPIB address appear and before the reset is invoked there is some response. It depends on the function button pressed I have either single short beep or some solenoid. In addition the display is acknowledging rear/front switch press displaying "Rear" segment.Just to test if CPU can detect an error and report it to the display I disabled communication with earth referenced logic.As previously all segments are lit followed by GPIB address but in addition "Error" segment is lit too.As previously the unit rests itself, now in longer 7 sec cycles.I checked all floated voltages 5v/18v/-18v and earth referenced 5V. All well with in spec with no excessive noise. I checked -15v/+15v on CR402/CR401/CR304/CR305/CR306/CR307 all good. Reference voltages +10V, -10V, 5V and 7V are OK too. Tantalums seem to be fine but I replaced a few with slightly higher ESR anyway.It appears the unit resets itself in sync with power on reset signal XPONRST. I lifted pin 5 on LM2725 but no change. XPONRST still present.What am I missing? Any help is appreciated.

author: Kwakerman
author_rank: Regular Contributor
timestamp: April 05, 2019, 06:24:31 am
content: Do all the power supply rails stay up during the reset process (just wondering if it may be the PSU dropping out and causing a reboot rather than a reset)?

author: henas
author_rank: Contributor
timestamp: April 05, 2019, 10:39:11 am
content: I recheck all the voltages including reference and they are rock solid, no dipping.

author: Samogon
author_rank: Frequent Contributor
timestamp: April 06, 2019, 04:38:36 pm
content: I would look at digital part, MCU RAM ROM.
TV Stuck On Startup Loop - Page 1
Forum section: electronics / repair

author: hillbillyhickey
author_rank: Newbie
timestamp: April 04, 2019, 07:47:56 am
content: G’day everyone, i’ve got a Bauhn Tv (it’s an Aldi brand), that is stuck on the startup loop, 1 capacitor was blown so I replaced it and tested all the others, they’re all fine. I cannot for the life of me find anything helpful online, everything/everybody says to check the capacitors and nothing else, so here I am.Thank you in advance to any good folk that help me.Sent from my iPhone using Tapatalk

author: fable
author_rank: Regular Contributor
timestamp: April 04, 2019, 08:10:36 am
content: What is the model name?

author: hillbillyhickey
author_rank: Newbie
timestamp: April 04, 2019, 08:17:19 am
content: It’s a Bauhn ATV-55FHDED mateSent from my iPhone using Tapatalk

author: Tajjbe
author_rank: Newbie
timestamp: April 04, 2019, 08:28:46 am
content: Have you checked the voltages from the voltage regulators? - Check if you have a steady 5V and/or 3.3V 12V or what other dc voltage supplys it got.

author: fable
author_rank: Regular Contributor
timestamp: April 04, 2019, 08:47:45 am
content: You will need to put new firmware via usb or by reprogramming flash ic

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 05, 2019, 06:28:10 pm
content: Sometimes firmware will get corrupt by the PSU failure, from my own experience it is more often a 24Cxx memory containing user and configuration data that gets corrupt, sometimes just blanking (FF ing) this memory is enough to escape the boot loop. Then having access to service mode can be a big help.
DYMAR 2081/100 service manual? - Page 1
Forum section: electronics / repair

author: tozitom
author_rank: Contributor
timestamp: April 06, 2019, 09:48:21 pm
content: Just got this gear from an ebay auction, but seems to be out of calibrationand could not find service manual yet... Does anyone have it please? Would like to calibrate and give a full restoration too.Thanks
Metabo Powermaxx BS Quick - broken switch - Page 1
Forum section: electronics / repair

author: dziacial
author_rank: Newbie
timestamp: August 01, 2018, 09:37:20 am
content: Hi to everyone, this my first post.I have Metabo cordless drill with broken switch. To be specific MOSFET and diode released magic smoke. I can replace MOSFET with another one because is has markings. The problem is a diode. I have no idea what diode I should use. There is a photo of a broken switch:I have another quite similiar drill with the same switch. This on broke some time ago and was replaced under waranty to another with different diode.The switch is: Defond EGD-1112 B 12A 12VCan anyone tell me what diode I should use?

author: Zucca
author_rank: Unknown
timestamp: August 01, 2018, 10:10:54 am
content: Welcome!Terrible repair from the warranty guys! You can do much better than those monkeys.I would read the diode model in the "repaired" switch and search in the www an SMD diode with similar or bigger parameters....Since it looks like the diode is the weak point, I would go with one with bigger current capacity.

author: Marco
author_rank: Super Contributor
timestamp: August 01, 2018, 10:37:39 am
content: Would a TO277 Schottky fit? =>30V =>20A should be enough (given the 40A rating of the MOSFET).

author: dziacial
author_rank: Newbie
timestamp: August 01, 2018, 10:58:41 am
content: Quote from: zucca on August 01, 2018, 10:10:54 amI told them about that and they send my a photo of a few similiar switches claiming that they receved them from Metabo. I asume that Metabo is repairing broken switches or Defond changed diode because of frequent problems.Now that I look at this photo it looks like one diode have 2100 written on it. Could it be SB2100 schottky diode?

author: Zucca
author_rank: Unknown
timestamp: August 01, 2018, 11:07:22 am
content: yes, it looks good the SB2100.

author: Alan1
author_rank: Newbie
timestamp: April 04, 2019, 07:59:05 pm
content: Hi,What were the symptoms of broken switch, I occasionally get no rotation when trigger pressed......