hybridfree/eevblog-posts huggingface dataset:
100 Ohm L&N Resistance Standard. What kind of oil fills precision resistors? - Page 1
Forum section: electronics / repair

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: May 31, 2020, 03:24:25 pm
content: General question that somebody may know an answer to...Some time ago I've bought a resistance standard. I believe it was L&N, 100 Ohm, that was faulty... and empty.I believe somebody was trying to fix it and they couldn't find the problem. It was showing as open.Of course the wire right by one of the terminals was open. I've fixed a problem but wanted to see if I could restore it to specs.It's pretty much spot on. I've taken some measurements but don't remember now.. it was some time ago. Being oil-less affects its stability.Also... another question... how full suppose to be container when you fill it with the correct oil... completely full or not.I'm just afraid that if I fill it to the brim the changes in the temp and unavoidable expansion will make it leak.How tight suppose to be the container?Should I seal it with... silicon or is there a better, correct material to do so.How to test it after restoration, refill and seal?What would you use to check the performance.

author: Gyro
author_rank: Super Contributor
timestamp: May 31, 2020, 03:56:53 pm
content: This thread might help...https://www.eevblog.com/forum/metrology/oil-for-a-leaking-tinsley-standard-resistor/

author: tggzzz
author_rank: Super Contributor
timestamp: May 31, 2020, 05:35:29 pm
content: Beat me to itA little research often brings dividends, but it does help if you remember topics!

author: Gyro
author_rank: Super Contributor
timestamp: May 31, 2020, 06:24:59 pm
content: My failing memory and trigger finger aren't as bad as I thought!

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: June 04, 2020, 03:02:05 am
content: Thank you all. I think I have mineral oil somewhere here... still debating how much space to leave in the container for expansion... will report when done.

author: coppercone2
author_rank: Super Contributor
timestamp: June 04, 2020, 03:44:20 am
content: I think you need to boil it for a while, let it cool, and seal quickly. Don't seal it hot though.

author: Gyro
author_rank: Super Contributor
timestamp: June 04, 2020, 12:57:29 pm
content: I don't see why boiling it would help.Certainly don't start messing with the resistor and hot oil - you don't want thermal shocks.
1013d oscilloscope  - Page 1
Forum section: electronics / repair

author: Mal
author_rank: Newbie
timestamp: February 01, 2022, 08:07:34 pm
content: Would anyone know what screen will fit and work,all I know is it is a capacitive touch screen and is 7"and where can I get one please

author: bob91343
author_rank: Super Contributor
timestamp: February 01, 2022, 09:00:48 pm
content: More info needed. What company?

author: BrokenYugo
author_rank: Super Contributor
timestamp: February 01, 2022, 09:06:53 pm
content: No numbers on the panel assembly?

author: Mal
author_rank: Newbie
timestamp: February 02, 2022, 01:47:08 pm
content: The number on the back is hz-tft070ie001 I carnot find this number anywhere the only one I've seen is w v g a at070tn90or the other model 92 it is made by fnirsi.there eas someone on this site that fixed one with a different screen but I can't find it anymore I would be grateful if anyone can helpFnirsi was not helpful in any way at all, my screen is cracked at the top right corner and won't work at all, it does light up but that is all

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 09, 2022, 04:24:17 am
content: A bit late because I did not saw this post till now, but all the information you need can be found here:https://github.com/pecostm32/FNIRSI-1013D-1014D-Hack/blob/main/Aliexpress%20links%20to%20handy%20stuff
1070 GPU. DVI port removed, wire in its place, why? Stuck on low clocks too. - Page 1
Forum section: electronics / repair

author: FM
author_rank: Newbie
timestamp: January 13, 2024, 01:53:42 am
content: I got this last week. Gigabyte 1070 video card.DVI port is removed. I don't know why.A wire is soldered across two spots where it looks like the DVI port was. I don't know why.I've read of people simply ripping out DVI ports and the rest of the cards still working fine. Never read anything about soldering a wire in there for some reason.The card seems to work fine, except it's stuck in 2d low clock speeds. While starting a game or benchmarking, the clocks may momentarily increase to around where they should be, then goes way back down and stays there.DVI port completely removed.The HDMI port apparently doesn't work at all.All three displayports work.I've tried forcing higher clocks with MSI Afterburner, and setting Max Performance in Nvidia driver utility, but they still do the quick spike up and then stay back down. The main problem with this card is the low clock speeds, but the soldered wire is interesting too so figured I'd post it and see if anyone had some ideas why the card is this way.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 13, 2024, 02:32:37 am
content: the wire connect the dvi pcb support ? dont know why, unless the ground is not common, remove the remaining pins with a fine cutter, they may short, if the hdmi doesnt work that could be another problemremoving dvi, it's a joke and change nothing, just create problemstry to find display port to hdmi cable it will be fine ...but personally i would toss the card, hs was removed, you need to redo all the compound pad and or add thermal grease
1080 TI Mosfets - Page 1
Forum section: electronics / repair

author: blendfish
author_rank: Newbie
timestamp: October 19, 2020, 05:54:48 pm
content: HiAnyone know where in the UK it would be best to purchase some AOE6932 mosfets (or something similar enough that it works)? The only suppliers I can find are dodgy aliexpress ones with 2 month delivery times.If its just the mosfet that's damaged and I remove it with (i've got a rework station) would the card boot up without it?

author: blendfish
author_rank: Newbie
timestamp: October 19, 2020, 06:16:16 pm
content: Scratch that, finally found somewhere that would ship them out.
1080 TI Repair - Q546 - Page 1
Forum section: electronics / repair

author: Yaruns
author_rank: Newbie
timestamp: June 06, 2021, 02:57:12 pm
content: Unfortunately the component at Q546 on my GTX 1080 TI Founders Edition has fallen off and I am looking to order a replacement to solder back on.Does anyone know what this part is? I believe it said LP1 on it.Any help would be appreciated!

author: MathWizard
author_rank: Super Contributor
timestamp: June 06, 2021, 10:05:10 pm
content: nothing is showing up right away looking for the LP1 code, it could be a BJT, mosfet, or a dual diode for reverse voltage protection. What's the label on the 6-pin chip right next to it ?

author: Yaruns
author_rank: Newbie
timestamp: June 06, 2021, 10:31:59 pm
content: Thanks for the reply, the 6 pin chip is labelled K72.
10GbE Switch replacement part - Page 1
Forum section: electronics / repair

author: quarks
author_rank: Frequent Contributor
timestamp: December 09, 2021, 12:56:16 pm
content: does any one by chance knowm-tekPart# TG24102SIGI am looking for a datasheet and a source to buygoogle search did not show helpful results

author: asis
author_rank: Frequent Contributor
timestamp: December 09, 2021, 02:37:38 pm
content: Hi,Are these BASE100/1000 group transformers by any chance?https://datasheetspdf.com/pdf/921604/MAGTEK/G24102MK/1

author: quarks
author_rank: Frequent Contributor
timestamp: December 09, 2021, 07:15:27 pm
content: thanks for your replyit is a 10GbE switch, therefore I do not think these are Base 100/1000 parts, but I will double checkEDIT:asis gave a very good hintletters TG24xxx seem to indicate 10G Base-Thttps://en.mag-tek.com.tw/products_detail/160.htmand G24xxx is for 1G Base-Thttps://en.mag-tek.com.tw/products/46_49/1.htmbut still I have have not found a source to buy a TG24102SIGI have contacted service@mag-tek.com.twbut any other further hint is welcome

author: Mick B
author_rank: Regular Contributor
timestamp: December 10, 2021, 04:10:34 pm
content: Alibaba say they have them in stockhttps://m.hindi.alibaba.com/p-detail/hot-selling-electronic-components-tg24102sig-in-stock-1600372857000.html

author: asis
author_rank: Frequent Contributor
timestamp: December 13, 2021, 07:53:58 am
content: Hi,As far as I remember, we are talking about Cisco C3560-24TD (+ dual tranking port's)or C3560E-12D.DS-X2-FC10G-CX4 - Copper X2 transceiver.What could have happened?A thunderstorm on such short cables of 1-15m is unlikely to have contributed to the failure, and with Fiber Channel X2 SX / LX transceivers are even more so.DS-CAB-1M = 1m Cable for 10G Copper X2 transceiver,DS-CAB-15M = 15m Cable for 10G Copper X2 transceiver.Alibaba sometimes sells in lots.It is easier to find the used switch and dismantle the transformer from there.

author: quarks
author_rank: Frequent Contributor
timestamp: December 18, 2021, 12:13:55 pm
content: I do not know what happened, but one port 10G-Base-T is not working and when I opened up the switch one TG24102SIG showed blow/overheat sings

author: asis
author_rank: Frequent Contributor
timestamp: December 20, 2021, 09:24:24 am
content: Hi,The transformer is a consequence.The internal structure of the transceiver microcircuit is probably damaged.If the switch is multi-port, there can be several of them and, as a rule, they have a cooling radiator.If you have a pyrometer, try to determine which chip is by measuring the temperature from the bottom of the PCB.It is unlikely that you can restore working capacity: you need to find a donor and re-solder the BGA.Alas.

author: wraper
author_rank: Unknown
timestamp: December 20, 2021, 09:57:48 am
content: IMHO it's pointless trying to find the exact part. There should be plenty of substitutes readily available. There are only a few types of such transformers, and basically every manufacturer makes the same stuff. I suggest posting a photo and its dimensions.
1/15th HP shaded pole motor question, - Page 1
Forum section: electronics / repair

author: CaptDon
author_rank: Super Contributor
timestamp: May 06, 2025, 10:24:57 pm
content: My range hood has a 4 pole shaded pole motor rated at 1/15th HP. It is driven from a motor speed controller which appears to be a normal triac style device. Something is wrong with the old motor. It buzzes loudly when running directly from a variac (as it also does in the original range hood installation). It is rated for 120VAC 3 amps and rated at 1600RPM. By the time I put 50 volts on it, it is running at full RPM under the normal load of the twin squirrel cage blowers attached to it. Raising the voltage above 50VAC doesn't increase the speed, only the G forces of the vibration/buzzing. When running on the range hood speed controller it is already at full RPM at the low setting and turning up the speed control to max just increases the vibration and noise!! All of the same part number replacement motors are 'capacitor run' and rated 1625RPM 120VAC 1.0 Amp, a huge energy savings. My real question is can a capacitor run motor run o.k. at lower speed from the range hood speed controller? I am curious about the capacitor failing from the weird waveforms it may see at low duty cycle. Any thoughts?? Thanks!! (B.T.W., the bushings etc. on the old motor are in perfect condition and no sign of burning or damage to the windings. I am thinking maybe some bad segments on the squirrel cage armature?)

author: CaptDon
author_rank: Super Contributor
timestamp: May 07, 2025, 01:05:41 am
content: I have come to the conclusion this 4 pole 120VAC motor is acting like it is mis-wired internally. It makes full output at 60VAC!! Turning the speed controller to full speed doesn't increase the speed, it only makes the cabinets vibrate like they are going to come off the walls! It has been this way since we bought the house!! New motor time!!

author: bdunham7
author_rank: Super Contributor
timestamp: May 07, 2025, 01:11:38 am
content: Is it clear that the motor is supposed to be running at 120VAC at full speed? Perhaps the motor controller is supposed to limit it to 50VRMSor something like that. In any case, would a run capacitor as a voltage dropper fix it?

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 07, 2025, 11:45:07 am
content: Edit: I see bdunham7 had the same thought… I just type slower.If the rotor had some open segments, it could never reach full speed as the the torque would be significantly reduced and with the impeller mounted, so long as it is in its normal housing with the correct amount of airflow, it could never get to full speed due to the reduced torque.One thing not considered: that the controller is could be a single SCR, not a triac. If that’s the case, the most the most the motor would ever see is 60 volts. Maybe? Weird things have always been done to save a buck in consumer white goods…
121GW DMM port broken, looking for part - Page 1
Forum section: electronics / repair

author: bertramhuang
author_rank: Newbie
timestamp: June 12, 2020, 09:22:03 am
content: Last year I bought 121GW from eevlog official website, and been using it. It's working great still.The only problem is one of the DMM terminals seems lost the plastic piece and now when I insert the probe it is loose.It's gone over 1 year warranty though.Is there anywhere I can find this 4 ports terminal part or any similar part can be a substitute?

author: beanflying
author_rank: Super Contributor
timestamp: June 12, 2020, 09:30:14 am
content: You might like to drop an EMAIL to Dave directly. There was a batch late last year with some problems and buried in this thread just before and a little after were a few posts about ithttps://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2794226/#msg2794226

author: bertramhuang
author_rank: Newbie
timestamp: June 12, 2020, 09:48:48 am
content: Thank you beanflying. Thanks for the quick response and email sent

author: retiredcaps
author_rank: Super Contributor
timestamp: June 12, 2020, 04:54:05 pm
content: Another DIY possibility ...http://mrmodemhead.com/blog/fluke-banana-jack-repair/
121gw multimeter replacement battery terminals - Page 1
Forum section: electronics / repair

author: PL
author_rank: Contributor
timestamp: May 17, 2025, 04:35:33 am
content: Hi. I have a 121GW EEVBlog multimeter. The AA batteries leaked, and have corroded several of the battery terminals in the compartment. They pull right out so it would be easy to replace. Where might I buy those terminals? I've sprayed the compartment andthe terminals with contact cleaner and scrubbed with a tootbrush. Is there any other cleanup I should do? See attached photos.Thanks.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 17, 2025, 06:27:59 pm
content: Good Morning PL, I recommend you open up the meter, as I'm pretty sure you will find corrosion under the battery compartment.

author: J-R
author_rank: Super Contributor
timestamp: May 18, 2025, 03:42:12 am
content: I agree with the idea to open it up for a look inside.Also, I think vinegar will work the best to neutralize the battery deposits. It's what I use first, then once all the bubbles are gone I can assess the damage and contemplate options.If you still think you need replacements, private message Dave and maybe he could pull some contacts from one of his parts bin units and send them to you.
XW-20S  12V Battery Charger - Page 1
Forum section: electronics / repair

author: freda
author_rank: Regular Contributor
timestamp: November 12, 2023, 02:44:43 am
content: a NTC 10D-9, went MOhm,maybe the design does not handle some overload condition ?removed the mosfets, 09N65GX, RU7088R and checked okthe diode MBR20100CT is oki don't have a NTC 10D-9 replacement yet, so i thought i might check theusual suspects...the controller is the usual 3842,i'll have to rig up a test circuit for itnote no fuse, and no earth, its in a metal case! entirely dependent on insulationholding up on the pcb, some of the strands of the 240v lead in are frayed.....hilarious, just saw a utubhttps://youtu.be/glmC8J53h64
12V garden light connectors - Page 1
Forum section: electronics / repair

author: coppice
author_rank: Super Contributor
timestamp: January 31, 2024, 04:49:56 pm
content: There are a lot of Chinese made 12V garden lights available, which seem to have a similar 2 pin waterproof connector, which screws together, squeezing a sealing ring. Does anyone know if they follow a standard, or if they are just used for these products?
12v to 230v inverter - Page 1
Forum section: electronics / repair

author: p.larner
author_rank: Frequent Contributor
timestamp: February 14, 2024, 05:31:03 pm
content: I have a 600w mercury soft start inverter,its input was more or less a dead short,on investigation i found 2 banks of 4 fets, one of these was shorted between all legs,i replaced it but its still poorly,the 4 fets on the same bank/side of the pcb get hot in seconds,on further investigation all there gates have a squarewave drive but the waveform is riding on top of a 5v so the top of the peak is 12v the bottom of the squarewave is 5v,the fets are hard on as soon as power is supplied to the inverter,the pwm controler is a tl594 ic,any ideas what to check?.

author: Jwillis
author_rank: Super Contributor
timestamp: February 14, 2024, 08:13:05 pm
content: One bank of MOSFETs will be the low side (12V) and the other will be the high side (230V in UK) . What often happens is if one of the MOSFETs is shorted or a bank is shorted, that indicates that the inverter was over loaded. This usually destroys either the PWM controller and /or the the comparator.A good way to destroy a high frequency inverters is using electric motors (like power tools) because of the extreme inrush current of the power tool. The inrush current can exceed the maximum power rating of the inverter instantly upon startup.
12vDC to -400V DC-DC inverter - Page 1
Forum section: electronics / repair

author: daveyk
author_rank: Frequent Contributor
timestamp: November 11, 2022, 09:50:00 pm
content: Is anyone aware of any companies that make something close to this in a small package (~41mm x 53mm). I think the -400volts is a relatively very low current.The original MFG was German "tersteegen-electronic" that appears to be no-more.

author: jonpaul
author_rank: Super Contributor
timestamp: November 11, 2022, 11:06:16 pm
content: Endicot, coto-coil

author: Talli
author_rank: Newbie
timestamp: November 14, 2022, 04:19:08 pm
content: Go to ebay..Tons of sellers and different packages... Should be easy to find one... Close to that voltage
13 inch 2002 Sony crt. Need some advice. - Page 1
Forum section: electronics / repair

author: DC Jack
author_rank: Contributor
timestamp: July 26, 2025, 12:50:07 am
content: I found a neat little 13" Trinitron CRT on the curb and snatched it up. It's so cute! But it has a problem. When there is a change sudden change is brightness on the horizontal draw the picture loses linearity and it takes a couple of lines to recover. I've checked all of the caps in the HV section and the neck board that drives the tube and replaced a couple suspect caps, but none had outright failed. This did not solve our even reduce the problem.Any advice on what to try next, explain the theory of this failure. I have only worked on one other CRT and that was a few years ago and the problem was a shorted HOT did to a failed cap. That was easy. I didn't need to know much about CRT theory for that one.

author: benj38
author_rank: Frequent Contributor
timestamp: July 27, 2025, 08:18:01 am
content: Quote from: DC Jack on July 26, 2025, 12:50:07 amIf you look carefully at the picture you will see that this isnotthe case: there are many places where there is a huge change in brightness but no subsequent distortion.The picture looks like it is simply not adjusted correctly, mainly with respect to the various pincushion adjustments (upper and lower corner pincushion, etc.)Later generation Trinitron monitors had a plethora of geometry adjustments, and I would try to first see if the problem can be resolved this way.Also, keep in mind that you will never get a perfectly geometrically correct image on a CRT, but obviously what your monitor currently displays is not good.

author: Haenk
author_rank: Super Contributor
timestamp: July 27, 2025, 08:40:03 am
content: I had those issues with bad/cheap cabling. Good cables were quite expensive back then, with ferrite beads at both ends.Also sometimes had line noise coming from the computer, maybe leakage to the gound line.

author: amyk
author_rank: Super Contributor
timestamp: July 27, 2025, 08:58:14 am
content: Try a vertical gradient (brighter on top, darker on bottom or vice-versa) and see if the picture width changes proportionally.

author: Uunoctium
author_rank: Frequent Contributor
timestamp: July 27, 2025, 09:16:31 am
content: Silly question: is the input properly terminated?It looks to me like the signal level is too high.
1300w SMPS for amplifier, self oscilating, with unknown mosfets - Page 1
Forum section: electronics / repair

author: lazyman
author_rank: Contributor
timestamp: July 14, 2021, 10:23:36 am
content: Hi,I am trying to repair SMPS and amplifier. Made in china, with deleted markings from mosfets and ics. I know its based on some old self oscilating design, got it working with IRF840.Problem is, amplifier is declared 1300w at 4 ohms, has 7 pairs output transistors with 4 mosfets step driver, in class H.Died on generator, probably overvoltage, burned mov and exploded capacitors.I need help to indentify proper replacement mosfets for this power.

author: lazyman
author_rank: Contributor
timestamp: August 30, 2021, 01:59:43 pm
content: Maybe this can be of help. I cant find modern mosfet with such low treshold voltage and this big die. Treshold voltage is main problem

author: lazyman
author_rank: Contributor
timestamp: August 30, 2021, 02:09:39 pm
content: IRFP460N works, but i suppose its not good for 1300w.
13s ebike charger - Page 1
Forum section: electronics / repair

author: p.larner
author_rank: Frequent Contributor
timestamp: October 18, 2023, 08:54:42 am
content: i have a 13s 48v ebike charger with no output,its a greenway unit i think,it has a 7812 reg i want to check for op,is it best to probe between its output and carger neg op?.

author: soldar
author_rank: Super Contributor
timestamp: October 18, 2023, 02:54:32 pm
content: Quote from: p.larner on October 18, 2023, 08:54:42 amYou might get better response to your questions if you put a little more effort into your posts. Like provide more information, use proper spelling, punctuation, etc. Just a thought.
1440p ASUS 24" LED Monitor not working - Page 1
Forum section: electronics / repair

author: anilavermesh
author_rank: Newbie
timestamp: June 02, 2019, 02:49:10 pm
content: Hi All,My monitor recently stopped working and I've identified the following symptoms:When the monitor is powered on, the LED indicator lights upWhen powered, on startup, a few gray lines flash (where the ASUS logo normally appears) and disappear on a black backgroundNo signs of physical damage, cracks etcAny idea what the issue is?Help of any kind is highly appreciated, Thanks!

author: Rasz
author_rank: Super Contributor
timestamp: June 04, 2019, 01:15:47 am
content: check if its missing backlight with a flashlight
1602 Display Problem - Page 1
Forum section: electronics / repair

author: radiotek
author_rank: Contributor
timestamp: May 02, 2022, 09:27:05 pm
content: I just turned on my LC-100 LC meter and now the display is really weird looking.If I turn the display at a certain angle I can just about read what it normally displays and it looks like its working..Not sure what to do, I was thinking about disabling the back light but I really do not think it would help.Any idea what these characters are that are being displayed and how to get rid of them ?Any help would be appreciated.

author: TheMG
author_rank: Frequent Contributor
timestamp: May 02, 2022, 09:44:51 pm
content: That's the contrast setting is out of adjustment. Is there a contrast adjustment pot somewhere on the board? It could also be a soft function.

author: jeremy
author_rank: Super Contributor
timestamp: May 02, 2022, 10:04:16 pm
content: Agree on the contrast setting. It is usually controlled by the VO pin on the display, maybe measure the voltage there and see if it is sensible? Also, have a look on the PCB if possible and see what connects to that pin.

author: metrologist
author_rank: Super Contributor
timestamp: May 03, 2022, 04:02:21 am
content: Scroll down for the contrast mod, or change value of R1.https://vk4ghz.com/lc100-a-lc-meter-mods/
18V Charger Replacement  - Page 1
Forum section: electronics / repair

author: vidarr
author_rank: Frequent Contributor
timestamp: August 11, 2023, 07:41:18 pm
content: The charging "station" for my drills broke. While I am waiting for the replacement parts to arrive, I need a quick fix, so I don't lose work. There are a lot of videos online about using a laptop charger/psu to charge 18V tool batteries. This is far from ideal, I know. My question is, of the four outputs of the charger (original), which two are the power supply? My first guess was the Red and Black, but then I was thinking maybe it is the Red and Green.If the charger was working, or the batteries had any charge, I could figure this out easy enough. I looked up the pinout for the charger and cannot find anything. So, can someone help me determine which two outputs of the charger (inputs of the batteries) are the positive and negative?Thank You!

author: vidarr
author_rank: Frequent Contributor
timestamp: August 11, 2023, 07:44:21 pm
content: Here are a couple extra pics.

author: inse
author_rank: Super Contributor
timestamp: August 12, 2023, 05:42:53 am
content: If you plug in the battery you should be able to measure the voltage on the according cables.If there is not a single Volt left in your battery pack, you have an additional problem.Nevertheless I would assume red+ black- green,yellow temperature sensor and maybe some coding of voltage or capacity

author: thephil
author_rank: Regular Contributor
timestamp: August 12, 2023, 12:08:54 pm
content: What brand is it? That would help finding someone who can help – e.g. by quickly measuring their own battery.
+/- 18v DC_PRT ?? understanding Power supply . - Page 1
Forum section: electronics / repair

author: jeremiah goike
author_rank: Newbie
timestamp: October 08, 2022, 09:29:59 pm
content: Hello,I am attempting to modify a small Yamaha MS101-4 powered studio monitor/powered speaker.I need to make it run on 12VDC battery power and It currently takes only AC power.The internal ac/dc power supply puts out +24VDC with ground and also +18,-18 with ground.I am proficient enough to implement 12VDC DC to 24VDC DC step up and also to find something for the +/- 18VDC BUT....There is a additional pin that is labeled "DC_PRT" and I don't know what that means.See photo.I am hoping someone here can fill me in on this and possible coach me on what to do with that pin.Also, if someone knows the 2 different series 'molex' style connectors used that would be amazing!

author: fzabkar
author_rank: Super Contributor
timestamp: October 08, 2022, 10:18:04 pm
content: DC_PRT = DC Protect ?Power amps sense the presence of DC on their outputs and go into protect mode if it exceeds a certain threshold. Usually there will be a protection relay.

author: jeremiah goike
author_rank: Newbie
timestamp: October 08, 2022, 10:24:34 pm
content: Ah, thanks DC protection, that makes sense.Curious how I should deal with this as I am hacking together a way to run this speaker on DC only and remove this ac/dc power supply.I wish i knew someone I could just hire for this project!!

author: DrGeoff
author_rank: Frequent Contributor
timestamp: October 08, 2022, 11:11:16 pm
content: For a project like this, two immediate solutions spring to mind.1) Get a small inverter and continue to power the speaker off the mains from the inverter. No mods needed.2) Rather than attempting to redesign the power supply, refit a new amplifier that runs from 12V. Probably a class-D amp and a simple preamp/input circuit. Then you can eliminate the old power supply completely and replace the innards with something simpler.

author: jeremiah goike
author_rank: Newbie
timestamp: October 09, 2022, 07:47:38 am
content: Those are not bad ideas, thanks.I'm afraid the inverter would likely introduce unwanted noise into the power.A 12v amp would loose functionalities and likely quality of the internal amp which has tone controls and multiple balanced and unbalance inputs, it would be tough to emulate or retrofit while keeping those functionalities
18W USB-C TS80 LCD backlight when out - Page 1
Forum section: electronics / repair

author: FranticKoala
author_rank: Newbie
timestamp: May 21, 2020, 09:50:15 pm
content: On the recommendation from video #1114 and what my needs are I purchased a TS80 about a year ago I have used it multiple times a day almost every day since i got it. It has been wonderful!The problem came a couple months ago when the screen "backlight" when out. It was quite hard to read but still worked. Recently though the screen had got so dim that 90% of the time I am not sure if it is on or not.I re-flowed the screen connector and most of the chips on the PCB. That did not fix the issue.What I don't know now is if it is actually a screen issue or if it is something else. If it is the screen itself does anyone know where i can get a replacement (The screen model number is quite hard to read).Thank you for any help. FK

author: chriva
author_rank: Regular Contributor
timestamp: May 21, 2020, 10:06:46 pm
content: They have an OLED display so unless it has power delivery issues, it'd need a new display
1938 Hallicrafters SX-16 Meter Repairman? - Page 1
Forum section: electronics / repair

author: Henry Finley
author_rank: Regular Contributor
timestamp: July 26, 2023, 01:00:21 am
content: The S-meter on my old Hallicrafters has a broken needle return coil. It's a right-side-zero type. Does anybody know where I maybe able to send it for repair? I'm in NC, USA Thank you
1984 Vintage PC : power supply ripple ? - Page 1
Forum section: electronics / repair

author: CeD
author_rank: Contributor
timestamp: November 07, 2020, 06:27:00 pm
content: Hello everyoneI'm trying to fix a toshiba T1100 ; this is "the first laptop" (at least by toshiba) and it's a very old 1984 pc powered by a 80c88, it has 256Kb of RAMCurrently, it boots "one time out of ten". It seems something fails to "start" properly.Probind around, I can see the voltages are somwhat ok, and the CPU gets its 4,77Mhz clock.But nothing happens 9 times out of 10. I stripped it down to the bare motherbaord ; same symptoms.The problem IS on the motherboard.I'm not really used to DC-DC boost converters,This uses a 12V battery ( that I redid, and is brand new) to generate 4 voltage rails+12V (blue)+5V (yellow)-5V (pink)-12V (cyan)I'm trying to figure out wether or not the levels of "ripple" I see are OK or not,I have no experience whatsoever with thoseThis is with averaging onThis is probably more accurate, and is with averaging off.At worst, we got low frequency (33Khz) ripple of around 100mV on the 5V rail (yellow)And maybe + and -75mV (let's say 150mV) if we take into account what seems to be high frequency stuff.Doesn't sound too bad to me but again, never had any experience in such DC-DC Buck boost converterAny opinion ?

author: BobRyan
author_rank: Contributor
timestamp: November 08, 2020, 04:09:04 pm
content: Try taking those measurements again but use different probe grounding techniques as described inhttps://e2e.ti.com/blogs_/b/powerhouse/archive/2016/07/27/how-you-measure-your-ripple-can-make-you-or-break-you
1N920 diode substitute advice please - Page 1
Forum section: electronics / repair

author: fudmuffin
author_rank: Contributor
timestamp: January 30, 2020, 11:07:12 am
content: Howdy,I have an oldschoolTelevideo 925 terminalthat I would like to get working. I've detected one of the diodes as blown in the video circuit and hoping for advice on suitable replacement. I should mention that I am being extremely cautious around the CRT and Flyback transformer, which can hold adeadlycharge, even though it is only a diode that I am wanting to replace.The diode is D301 on the schematic and listed in the parts list as an1N920. Any suggestions on most suitable readily accessible replacement?I have some 1N5819 diodes on hand among others but not really sure they'd be suitable.I have attached:* The schematic with a red arrow pointing to the diode.* The parts list for the video section.* 1N920 spec sheet.* Some pics of the pulled diode. Markings seem to be something like a "K" and "O".

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 30, 2020, 12:15:07 pm
content: Hi,I would try a 1N4935. These should be easy to get.Jay_Diddy_B
1st time Deoxit D5 user. Is the Windex smell normal? - Page 1
Forum section: electronics / repair

author: Cliff Matthews
author_rank: Unknown
timestamp: June 07, 2019, 04:48:47 pm
content: Bought it locally this morning (@ $25 CAD ~18 USD it was priced better than Amazon.ca) could this be a fake?Not only the smell caught me off guard, the over-label did too (turned-out it's a just a bilingual Canadian thing..)

author: Bill158
author_rank: Regular Contributor
timestamp: June 07, 2019, 07:55:27 pm
content: I get a smell more like a weak RAID or pesticide, but it could be a windex smell also.Is the liquid a weak Red in color?Bill

author: Cliff Matthews
author_rank: Unknown
timestamp: June 07, 2019, 11:20:29 pm
content: Well, if you mean weak red, as in red-shift in stars, I think so. I sprayed it on some paper and it's so fine it soaked fast through instantly onto a metal surface below. So I let both sit for a few hours. FWIW, I wanted to go slow since this will be sprayed into pots on a vintage TEK T935A scope. See what you think..

author: amyk
author_rank: Super Contributor
timestamp: June 08, 2019, 01:19:02 am
content: Certainly does not help that the MSDS lists the ingredients as "trade secret - proprietary"

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: June 08, 2019, 01:40:46 am
content: Well, it's not oleic acidhttps://www.garagejournal.com/forum/showpost.php?s=9138ce5514faa80c16c87321b4bd536b&p=5086165&postcount=10

author: Cliff Matthews
author_rank: Unknown
timestamp: June 08, 2019, 12:01:12 pm
content: Quote from: amyk on June 08, 2019, 01:19:02 amYou're right, I wasted $25at the top of the 2nd page..

author: Bud
author_rank: Super Contributor
timestamp: June 08, 2019, 12:21:27 pm
content: Where did you buy it ?

author: Cliff Matthews
author_rank: Unknown
timestamp: June 08, 2019, 05:32:00 pm
content: Quote from: Bud on June 08, 2019, 12:21:27 pmKW Surplus in Kitchener (https://goo.gl/maps/7VThNont2zrzT2RY7).AFAIK, they just started carrying it, so if you're closer to the Cambridge or London stores, check them first.
2.4 ghz r/c toy cars Tx and Rx issues - Page 1
Forum section: electronics / repair

author: sainbablo
author_rank: Regular Contributor
timestamp: September 27, 2023, 06:24:15 am
content: HiWould a knowldgeable individual please point to right place for discussionabout Tx and Rx issues of 2.4 ghz toy cars? Thanks
2013 Sole 85 threadmill stopped working - Page 1
Forum section: electronics / repair

author: speo
author_rank: Newbie
timestamp: March 30, 2025, 08:52:20 pm
content: First, let me tell you a few words about myself: 56 years old, soldering since I was 10, good understanding that electricity is not a joke, but not to be trusted when it comes to electronics, I need some help repairing my treadmill.When I was walking on the treadmill today I heard a pop (sounded like an electrical pop) and the band stopped moving. The sound came from the front lower part of the treadmill, where the motor control board is located. The LCD panel is still working, the buttons are still working and performing the right tasks on the screen. On the screen it is showing that I am starting, stopping, programming it, but just the motor is not spinning and the band is not moving. A little bit of smell of burnt electronics also came from the same area where the pop sound came from.I unplugged from the power outlet, I opened the cover, and I can see some green LED coming on when I power the treadmill, the LCD works fine, buttons are working fine, but when I start a program, the band doesn't move, so it's powering fine, no fuse or transformer issue.I disconnected the DC motor and powered it up with a 12V 7Ah battery and it is turning and moving the belt with ease, so I think the issue is the motor control board. Visually I cannot see any obvious damage on the board.This is where my debugging skills reached the limit. Unfortunately, even if the motor and the board are covered by lifetime warranty, I don't have the receipt anymore. I will buy a new board, but I am also interested to see if I can fix this one, and this is where I need your help. If I am able to fix it, at least I'll have a backup board.My best guess would be first to test the power FET's, I guess that's what those 3 parts with heat sink are...Threadmill model: 2013 SOLE 85Control board:https://www.sole.parts/solef85motorcontrolboard2013-2015Motor:https://www.sole.parts/sole-f85-2013-drive-motor.htmlMotor specs: 90V, 30A, 4000RPM, 4HPThanks, any help would be appreciated.

author: speo
author_rank: Newbie
timestamp: March 30, 2025, 10:48:31 pm
content: I think I found the problem.After removing the control board I had better access to visually inspect it and it's obvious one of the FETs is burnt (first pic) and I think the reason is the white piece that conducts heat that was supposed to sit behind that FET moved away to the left and the FET couldn't cool properly (see second pic). The issue is, it appears that when it popped, it damaged a piece of the PCB tracing as well. Can I run a solid wire instead of that tracing?

author: Zero999
author_rank: Super Contributor
timestamp: March 31, 2025, 07:31:43 am
content: Quote from: speo on March 30, 2025, 10:48:31 pmIt isn't a FET. It's a dual diode, hence the symbol printed on the package.https://www.vishay.com/docs/88597/fep30xp-e3.pdfIt's certain other components have failed. Definitely the MOSFET and possibly the controller IC.
2020 iRobot Roomba i3 - need guidance - Page 1
Forum section: electronics / repair

author: Synoptic
author_rank: Contributor
timestamp: February 15, 2024, 08:35:55 pm
content: Hi there ! In an attempt to repair a 2020 Roomba i3, I would like to seek if someone here wants to help me.Symptoms : Looks stuck in a boot loop. (led does circle, then stops for 1 second and redo the same circle).I have opened up the machine and already started probing the PCB.Probing some of the Test Points on the PCB, I found a serial communication channel that spitted out some information : seehttps://pastebin.com/eQiVSRGBfor a log capture.The serial stuff comes from the big STM32F303, probed on TP2I was hoping to find a bootloader message or something that could help me find something like a corrupted boot image or something, but nope.https://imgur.com/a/QNYgkPv

author: markusdd
author_rank: Contributor
timestamp: February 25, 2024, 02:00:28 pm
content: surprised no one commented here: are you still debugging this?The log messages show one error consistently: it complains about some 'emitter control' being busy and then there is this error, all of this somehow points to the charging circuit:  Emitter ctrl 1: Busy, will try again 0M)  sending turn ON cmd at 111M6U  ERROR send cliff emitter control 1 failMab  onlineM/P RPC Switched pwr voter 2 set vote to 1MG.  saw charger contacts rising 1 falling 0, keep emitters onM`  insertedMA4g  voter 2 votes to turn bin emitter 1 (1: on 0: off)M;  onlineM2TD  initial safety cliff cal requestedM18P  cliff cal read ctrl: send successM  init done!M*R  Emitter ctrl: send successM)EI am not sure when they say emitter they mean emitter of a transistor, possibly some software speak for some event happening or so.have you checked the circuitry around the battery?

author: Synoptic
author_rank: Contributor
timestamp: February 25, 2024, 02:33:22 pm
content: Hi! I stopped debugging and sold the robot.The emitter in my opinion is the high-level definition of some infrared sensor that detects voids/edges (stairs for example).Without schematics and a comprehensive manual, this mission was getting too difficult for what it was worth.Thanks for your help!

author: markusdd
author_rank: Contributor
timestamp: February 25, 2024, 04:13:10 pm
content: sure.yes without any docs this kind of stuff can get almost impossible to track down, good catch on the log though...this is wayyyyy more than you usually get.
2024 signal generator power switch - Page 1
Forum section: electronics / repair

author: clemmi
author_rank: Newbie
timestamp: June 11, 2023, 09:38:39 pm
content: My Marconi Signal Generator 2024 has a bad power switch. Otherwise it works fine.How can I replace the power switch with same or add an external one if replacement is not available.I searched the site and found no help, repair companies do not want to do this repair.--> I can use schematic to replace with an external switch, it has four cables going to it.Thank you for any ideas. wd6y@arrl.net

author: Hamelec
author_rank: Regular Contributor
timestamp: June 12, 2023, 10:06:23 am
content: Hi Kal,look for something like that:https://www.digikey.de/en/products/detail/e-switch/P227EE2B18A/210544..you have to check the dimensions73, good luck

author: clemmi
author_rank: Newbie
timestamp: June 12, 2023, 04:51:04 pm
content: Thank you. i got a simple DPDT switch to mount on the front.It would be easy if I found the diagram of which cable goes where.

author: andy3055
author_rank: Super Contributor
timestamp: June 12, 2023, 07:44:16 pm
content: Elekrotanya has it. Just Google for Marconi 2024 schematic.

author: Hamelec
author_rank: Regular Contributor
timestamp: June 13, 2023, 12:30:23 pm
content: a circuit diagram to rewire the power switch ?you are kidding..
20MB MFM HDD spindle motor speed control - Page 1
Forum section: electronics / repair

author: fzabkar
author_rank: Super Contributor
timestamp: September 01, 2020, 10:55:05 pm
content: This is not strictly a repair question, but it follows on from this thread:https://www.eevblog.com/forum/repair/ambient-temperature-dependant-fault-(old-mfm-hard-drive)/In that other thread it appears that the 10MB MFM HDD has a trimmer to adjust the speed of the spindle motor to a tolerance of +/-1%. ISTM that this kind of design is asking for trouble, so I then looked at the design of a 20MD HDD that was supplied with the IBM PC-AT.Here are the circuits from IBM's Tech Ref Manual:http://www.users.on.net/~fzabkar/PC-AT/AT_20MB_HDD/AT_20MB_4_50.jpg(spindle motor + stepper positioner)http://www.users.on.net/~fzabkar/PC-AT/AT_20MB_HDD/AT_20MB_3_50.jpg(read/write analogue circuits)http://www.users.on.net/~fzabkar/PC-AT/AT_20MB_HDD/AT_20MB_2_50.jpg(digital logic for motors)http://www.users.on.net/~fzabkar/PC-AT/AT_20MB_HDD/AT_20MB_1_50.jpg(uC + MFM interface)AFAICT, HE0, HE1, HE2 are the Hall Effect outputs from the spindle motor and are used for commutation. HE2 provides the Tach for the uC. The motor also produces an "R Index" signal for the uC. There are 3 phases -- 0A, 0B and 0C.AISI, there is only one way to control the speed of the motor, and that is by PWM-ing the -MOTOREN and/or MOTOR signals. Would that be how it is done?

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 02, 2020, 07:09:25 pm
content: Although I'm no expert on the matter I suppose the same.-MOTEN seems more convenient to PWM considering C4 on MOTOR line.
222K inductor? - Page 1
Forum section: electronics / repair

author: jbomba
author_rank: Contributor
timestamp: December 09, 2020, 01:55:57 am
content: Hey guys im repairing a speed controller for a client as the controller is well over $1000 aud. i have found an open circuit inductor a blown resistor that links to a tny256gn ic. I plan to replace all 3 components. Would i be correct in assuming 222K stands for 2.2 mH? i have attached photo for reference. Planning to replace with the followinghttps://au.rs-online.com/web/p/products/1350142/

author: bob91343
author_rank: Super Contributor
timestamp: December 09, 2020, 05:41:20 am
content: Sounds right to me, although I am no expert. I would guess the K means 20% tolerance.

author: srb1954
author_rank: Super Contributor
timestamp: December 10, 2020, 06:50:04 am
content: Quote from: bob91343 on December 09, 2020, 05:41:20 amK is 10% toleranceM is 20% tolerance although this is rarely seen these days

author: bob91343
author_rank: Super Contributor
timestamp: December 10, 2020, 06:42:23 pm
content: Thank you, my error.
2246 distorted readout characters - Page 1
Forum section: electronics / repair

author: yannis
author_rank: Newbie
timestamp: May 29, 2021, 09:44:52 pm
content: 2246 passes all diagnostics successfully. Readout character dots are misplaced and appear distorted. Any suggestions or help how to fix the problem would be greatly appreciated.

author: rvalente
author_rank: Frequent Contributor
timestamp: May 31, 2021, 07:06:35 pm
content: I'd check if the eprom is correctly set in the socket as well as firmware checksum.

author: yannis
author_rank: Newbie
timestamp: June 02, 2021, 06:11:09 pm
content: Dear RVALENTE thank you for the reply. I reseated both eprom and rom chips that were on bases and check the chesksum of readout rom as well as system rom through diagnostics menu and they are ok. Unfortunately the problem remains. I can see a change in the misplaced readout dots (they move but still out of place) when I scroll the underline in the service menu window.

author: james_s
author_rank: Super Contributor
timestamp: June 02, 2021, 07:40:23 pm
content: The interesting thing is that the distortion is not consistent, the letter E for example is distorted in different ways in different positions. I wonder if it's related to the position of the character on the screen? I've seen vaguely similar behavior in old arcade game boards when there was a stuck bit on the output of a character RAM.

author: yannis
author_rank: Newbie
timestamp: June 06, 2021, 10:38:25 am
content: James_s thanks for the comment.The problem is so weird that I cannot figure out where to start from. Same characters are not only distorted differently on the same screen but they chance every time I move the underline with the up or down cursor. Initially I thought that the problem might come from PS capacitor noise since 33 years had past from the day I bought the scope from TEK as a student in the states. I recaped the PS but the character problem remained.

author: philwong5176
author_rank: Unknown
timestamp: June 07, 2021, 01:03:24 am
content: I want to remind you to replace ALL 17 ZM diodes. See thread below:https://groups.io/g/TekScopes/message/170804?p=,,,20,0,0,0::relevance,,17+diodes,20,2,0,762879242245, 2246, and 2247 Tek scopes all use the same power supply.I have a 2245A and a 2246.

author: yannis
author_rank: Newbie
timestamp: June 10, 2021, 07:11:46 pm
content: Thanks for the tip. I ordered the diodes and the old ones will be replaced as proposed.

author: james_s
author_rank: Super Contributor
timestamp: June 11, 2021, 04:25:29 am
content: How does the readout circuit work on these things anyway? Does it just step through eprom addresses and output the data to a pair of DACs?