hybridfree/eevblog-posts huggingface dataset:
Z-Wave lock depletes batteries - Page 1
Forum section: electronics / repair

author: danshtr
author_rank: Contributor
timestamp: January 22, 2019, 04:27:22 pm
content: Hi All,My Z-Wave door lock is using 4 AA batteries. They sometimes hold for weeks and sometimes they don't hold even for 48 hours.When the batteries deplete in a short period of time, I notice that only two out of 4 batteries are depleted, the other two are measuring 1.55V.Any idea how come batteries that are in series can deplete at a different rate?-Dan

author: Armadillo
author_rank: Super Contributor
timestamp: January 22, 2019, 05:02:35 pm
content: You didn't say if the batteries are all from the same NEW batch, so could be 2 old and 2 new.

author: danshtr
author_rank: Contributor
timestamp: January 22, 2019, 05:17:08 pm
content: All new batch. Tried two different vendors: Amazon and Energizer (bought from Energizer store at Amazon).

author: edavid
author_rank: Super Contributor
timestamp: January 22, 2019, 05:50:06 pm
content: Quote from: danshtr on January 22, 2019, 04:27:22 pmThere is probably an additional connection to the center tap of the battery string.

author: Armadillo
author_rank: Super Contributor
timestamp: January 22, 2019, 06:31:57 pm
content: The best is to confirm it with a multimeter set to ohms [if not auto then set to high ohm range].With the batteries out, black probe to known negative terminal and red probe to positions as shown.Only the known Positive and Negative should indicate a ohms reading.otherwise you may have a hidden circuit or a conductive leak from previous battery leaks, for example.

author: danshtr
author_rank: Contributor
timestamp: January 22, 2019, 07:12:37 pm
content: I have tested on all points, all showed out of rangeEDIT - forgot to add: the voltage on the "9V battery clips" is 6.3V

author: danshtr
author_rank: Contributor
timestamp: January 22, 2019, 07:19:27 pm
content: I might have inserted the battery holder upside down.I can not confirm or deny that the batteries had contact with the PBC directly...

author: Armadillo
author_rank: Super Contributor
timestamp: January 22, 2019, 07:20:10 pm
content: I forgotten to add;Your AA battery compartment must be hook/connected to the Z-Wave Lock for the measurement to be Correct, Otherwise you will be measuring empty space.But luckily, there is no conductive leak.Connect the empty holder into the circuit and measurement again to confirm.

author: Armadillo
author_rank: Super Contributor
timestamp: January 22, 2019, 07:21:05 pm
content: OK at least you have found the problem and solution.
Maha Powerex MH-C9000 replacement power adapter - Page 1
Forum section: electronics / repair

author: TheGrave
author_rank: Contributor
timestamp: January 21, 2019, 12:35:57 pm
content: Hi,My MH-C9000 adapter cable is about to die. Not something that cannot be repaired but opening up the power adapter will probably take quite some heating as it seems to be glued. Before I go down this road I want to order a replacement adapter. Anything you guys know that is compatible and easy to obtain (ideally with an EU socket)? Found some second hand stuff on eBay in the US but it will go up to 25USD with shipping and at this price point I'm thinking I might just as well take the leap and buy a brand new MC3000 for 3 times the price as 18650 and 26650 batteries started piling around my (internal charging) flashlights and headlampsOr maybe somebody who managed to open this adapter and nice enough to compile instructions?Cheers

author: Giorg
author_rank: Contributor
timestamp: January 21, 2019, 09:04:01 pm
content: any good quality 12V dc >=2A will do the job. Just make sure the plug is the same size!

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 22, 2019, 03:23:29 am
content: Quote from: Giorg on January 21, 2019, 09:04:01 pmyup its highly likely that the inside is just normal offline smps circuit like the rest, including the venerable pc atx psu and china hung low fixed 12V smps psu. the old plug can be reused no worry.
HP 209A Oscillator Stuck Fine Tuning Knob - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: January 22, 2019, 05:01:23 am
content: Hey Guys,I have project I am working on and wondered if I could get some input on these locked tuning knobs.The fine tuning knob was locked tight.I applied some penetrating oil to the shaft but can only get this shaft to rotate with a pair of vice grips. Replacing the knob just leaves it impossible to turn.Is there a lubricant that will get in there and loosen this shaft?Had a similar problem on a HP Sweep Oscillator of same vintage, that knob stayed a bit stiff after unlocking but it could be moved.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 22, 2019, 05:19:06 am
content: I've encountered different types of greases over the years in different equipment. Not sure what is in this one.Some of the grease I've had to clean up almost turned into a tar, and it couldn't be cleaned until the parts were separated. This may be a case of letting it slowly work over the course of a week or two. As you can see the shaft can get galled by the vice grips.Can the shaft be pushed out from the back if that inside cover and the main dial are removed? That's how other signal generator "fine" knobs were constructed in similar vintage equipment.Otherwise depending on the situation I've used:91% alcoholWD-40"Orange" cleanerOne of those Super Penetrating Oil things"Electronics" spray cleaner (check for paint and plastic compatibility)Automotive electrical cleaner (don't, damages paint and plastics)Brake cleaner (don't, damages paint and plastics)
Tektronix 7834 power supply defective. - Page 1
Forum section: electronics / repair

author: stfjohn
author_rank: Regular Contributor
timestamp: January 20, 2019, 04:56:48 pm
content: Hello everyone.Does anyone know how you can replace the condenser "C1237", apparently inaccessible?Thanks.

author: bd139
author_rank: Super Contributor
timestamp: January 20, 2019, 05:26:37 pm
content: Doesn’t the power supply just pull out as perhttps://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/rep-und-kal/7844_reparatur_engl.html?

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 20, 2019, 09:49:18 pm
content: Can you post a few pictures?

author: perdrix
author_rank: Frequent Contributor
timestamp: January 21, 2019, 03:00:17 am
content: C1237 is the tank capacitor, which is inside a metal box beneath the oscillator transistors.To get at it you pretty much have to completely disassemble the PSU. Refer to the Service Manual if needed. You need to remove the LV Regulator board, then the Cap Rectifier Board, then unsolder the leads to the transformer and the tank circuit and remove the inverter board (you'll need to unsolder the mains input leads too. Then you can remove the metal box containing L1237 and C1237 and open it up to get a the capacitor.How do I know - I just did all that with a 7854 supply.Good luck finding a replacement for that part - the original is 600Vrms (900Vdc), 0.03uf +/- 5%, 3.3A at 25kHz! I removed one from a 7904 supply which I'd kept for spares.PS If you are not already aware there are the Tekscopes and Tekscopes2 mailing lists on groups.ioCheersDave Partridge

author: stfjohn
author_rank: Regular Contributor
timestamp: January 21, 2019, 11:07:12 am
content: Thank you all for your help.Best regards.
iPhone repair using a CNC mill? - Page 1
Forum section: electronics / repair

author: tsman
author_rank: Frequent Contributor
timestamp: January 20, 2019, 11:14:31 pm
content: The PoP RAM on the Apple SoC had failed so they milled it off and replaced it. Desoldering just the RAM would have been difficult and replacing the SoC + RAM together would have caused it to no longer work due to mismatched crypto keys and chipIDs.They've done this before on other iPhones looking at their other videos.

author: stojke
author_rank: Regular Contributor
timestamp: January 20, 2019, 11:33:49 pm
content: At 3:04 the upper side of what ever is under the apple SOC doesn´t look too good.

author: Armadillo
author_rank: Super Contributor
timestamp: January 20, 2019, 11:40:04 pm
content: The CPU is bounded to the Touch ID, so CPU cannot be changed. The ram can freely change.I am sure DIY is different altogether. Watching is fun. Doing is another.I can say, with the underfill of the CPU below, installing the RAM above with application of hot air will be a huge huge challenge. Chances, are some of the lines will be shorted.Many iphone repair men will quickly not accept jobs of PMIC, CPU job, water damage jobs. Touch problem, VCC main etc.... they will grab.

author: amyk
author_rank: Super Contributor
timestamp: January 21, 2019, 02:27:11 am
content: Just wait for the Chinese to figure out how to hack the keying and release their tools, and everyone will be back in business... until Apple locks it down again, that is.

author: Armadillo
author_rank: Super Contributor
timestamp: January 21, 2019, 02:44:31 am
content: Then the Chinese better hack the cash card then hacking the touch ID because both are of the same category of "HARD".Not that I say they cannot but I think they can do better than spending their expertise on just the phone stuff. And then, you said it correctly, Apple can change it next waves of phones.

author: SilverSolder
author_rank: Super Contributor
timestamp: January 21, 2019, 05:05:39 am
content: That is very impressive handiwork... hats off!

author: texaspyro
author_rank: Super Contributor
timestamp: January 21, 2019, 06:05:29 am
content: Quote from: amyk on January 21, 2019, 02:27:11 amThey already have... at least for some models. Strange Parts did a video of a shop in Shenzen doing it. I think he then bought the hardware/software to do it himself.

author: bayati
author_rank: Contributor
timestamp: January 21, 2019, 09:19:17 am
content: Using CNC to remove bga ICs is an effective way, especially when adhesives are used to keep ICs tight. using hot air to remove big BGAs not just can damage the board but you can easily lift pads under the ICs and fixing them is next to impossible. I have change many emmc and cpus but still it takes more than an hour to remove adhesives. I am planing to buy (or if possible build) one of these CNCs.
Primadonna Elite Experience ECAM650.85.MS Frother Probem Will Not Pump Milk From - Page 1
Forum section: electronics / repair

author: unixpro
author_rank: Newbie
timestamp: January 21, 2019, 07:32:27 am
content: Hi Everyone,I have Primadonna Elite Experience ECAM650.85.MS that is relatively new (about 6 months) and used maybe once or twice a day. Recently I noticed a problem with frothing process in all milk based drinks - when steam is entering milk jug it's not able to lift or suck milk into jug head for frothing. As a result no milk or foam coming to the cup. Hot water and tea functions work well, water heats up.Descaled machine after I noticed this problem, disassembled and cleaner milk jug (there was no sign of milk stone).Any suggestions how can I further troubleshoot this?This is video of the process:Also could someone please advice where can I get service repair manuals for this model?Thanks in advance!

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 21, 2019, 07:55:09 am
content: Is it under warranty? Can't you ask in the shop if its still valid after you disassembled it?

author: unixpro
author_rank: Newbie
timestamp: January 21, 2019, 08:05:48 am
content: Quote from: nsrmagazin on January 21, 2019, 07:55:09 amIt might be. However I live in US and this is non-US model (220V), so DeLonghi in US denies even answering a simple question over the phone or e-mail about non-US model.
need help - Page 1
Forum section: electronics / repair

author: hudex
author_rank: Newbie
timestamp: January 20, 2019, 10:06:28 pm
content: can we use 4145 S.P.A. to measure the characteristics of the printeed device.if can then how any links will be appreciated please help

author: shakalnokturn
author_rank: Super Contributor
timestamp: January 21, 2019, 12:06:54 am
content: Could you be less precise?
Industrial SMPS sound - Page 1
Forum section: electronics / repair

author: additive
author_rank: Newbie
timestamp: January 20, 2019, 12:07:11 pm
content: Hello all,I am trying to fix a SMPS from an industrial robot.Long story short it has 3 x 24V outputs and 1 x 5V output, 24V outputs have MOSFETs at the outputs to turn them off when something is wrong and LEDs to indicate it.This specific power supply had 24V problem (LED on and 24V outputs measured 0V), so I took it apart, tested all MOSFETs, diodes, some resistors, capacitors and opto-isolators also and could not find any problem. Only the fans needed a gentle push to start spinning.I only replaced MIP0223SY chip, just in case (It seems to be responsible for generating 5V, 22V and some more voltages for the rest of the board).Then I assembled it back together and everything seems to work again. No red LED turned on and all outputs measured ~24.4V.Only problem is this sound that I can not figure out, it does not seem normal for me.I readhttps://www.repairfaq.org/sam/smpsfaq.htm#smpsstsmunder "Sounds that SMPSs make" that it might be caused by improper loading, so I tried with 2 x 47 Ohm 11W series resistors at the output. It worked longer, but after ~3 hours of running the sound still returns.When I probe the circuit with multimeter at the MOSFET, which gate is driven by NCP1563A (power factor correction chip), the sound will change.Unfortunately I could not find any schematic for this power supply. If needed I can try to explain more from what I have understood after tracing the tracks.Here is a short video:Also some images:Thanks for your time

author: coromonadalix
author_rank: Super Contributor
timestamp: January 20, 2019, 01:26:04 pm
content: The sound change is because of the meter impedance (supposed to be in the 10 megs range unless its an bench dmm who has giga ohms impedance say 0- 20vdc)Be careful when you probe, you may toast the smps while doing so, if you make some frequency changes or feedbacks changes while probing the smps may react badly.

author: additive
author_rank: Newbie
timestamp: January 20, 2019, 05:59:02 pm
content: Thanks for the heads up coromonadalix!I wrapped some wire around transformers and inductors today and performed measurements with oscilloscope.CH1 is MOSFET gate driving transformerCH4 is output transformerCH3 is around output inductor5V part:24V part:So yeah, this power supply seems far from fixed.I also found out for sure, which transformer was making the noise. But it does not seem important anymore, because of the pictures above.It is not worth searching any further I'm afraid.Thanks for the attention guys!
Can you offer a cross ref for this part? - Page 1
Forum section: electronics / repair

author: billbyrd1945
author_rank: Regular Contributor
timestamp: January 19, 2019, 02:57:49 pm
content: My project uses this chip: SONIX SN8P2711APB (14 pins).I can find plenty of them on ebay but would like to find a newer version of the thing with a datasheet I can understand. The datasheets available for this one don't really show pinouts in a way that this noob can make sense of. Mainly need to know VCC and ground. Thanks

author: Armadillo
author_rank: Super Contributor
timestamp: January 19, 2019, 03:15:44 pm
content: Datasheet Very Clearly Describe. Freely available.Don't understand your question, really.VDD = Voltage to Digital Circuit (Positive 5V power supply)VSS = GroundFor starting out with Microcontroller, start with the Right processor that can sustain you with many projects and active community discussions in the market.I recommend you to start with Atmel AVR [now bought over by microchip], chiefly the Arduino/GCC compilers and Atmel studio are freely available and kits are cheaply abundances and fast controller.for 14 pins for example, you can start with ATtiny84. Pinout will not be the same.

author: PKTKS
author_rank: Super Contributor
timestamp: January 19, 2019, 03:39:43 pm
content: Quote from: Armadillo on January 19, 2019, 03:15:44 pmTRUE.But STM is not that far awayAVR DUDE can handle their gizmos just fine as wellAnd ALIExpress has literally dozens of gizmos to interface both ATMEL and STMPaul

author: Armadillo
author_rank: Super Contributor
timestamp: January 19, 2019, 05:06:06 pm
content: Just like climbing the ladder, One Rung at a Time or you will easily quit trying and never reach.Take the baby step if you are new with VCC and VDD.The important is having fun while enjoying and not pulling your hair out trying and give up half-way.
Low power indicator warning misreading. - Page 1
Forum section: electronics / repair

author: jerb
author_rank: Contributor
timestamp: January 19, 2019, 09:13:12 am
content: Have a point and shoot film camera i'm trying to repair. 2 actually. same problem but slightly different.So the battery is in fact fully charged and good to go there's no issues battery side, contacts are clean no corrosion or any issues like that.There seems to be some sort of short in these things that i can't figure out how to address.The camera on the first one believes the battery is completed dead, so it will refuse to turn on.The second one the battery shows 1/4 and flashes as if it's dying but it'll power on and still function but won't charge the flash as is the feature of low battery preservation.These are semi difficult to take apart due to the nature of their soldering but so far i took one apart and replaced 3 tantalum caps with 47uf 10v electrolytics and no change.There is one tantalum left by the IR sensor, but i don't think they're the issue. I'm trying to understand which circuit may be responsible for power sensing or if it's simply just the main ic that has gone bad.There is one chip under the top main board, maybe a sop32 or something i stupidly didn't get a good enough look at it while i took it apart the first time as i thought it was just the caps.I also replaced the Flash capacitor as i thought it was possible, but it was originally a rubycon so i really didn't think that would be the issues. * spoiler it wasn't.Anyway any advice is much appreciated!
Busted SOURCE output on HP89410A (HP89441A) - Page 1
Forum section: electronics / repair

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: January 19, 2019, 08:58:14 am
content: I have a HP89441A (rebadged HP89410A) with dead SOURCE output.All the calibration and self-tests pass fine but the output is completely dead.Is there a CLIP or schematic of the Analogue Source module A35?CheersLeo
Simracing Wheel thrustmaster tx ferrari 458 italia (t300) totaly dead - Page 1
Forum section: electronics / repair

author: dbach1958
author_rank: Newbie
timestamp: January 18, 2019, 05:11:02 pm
content: Hello Forum, it's my first post here.I bought a used Thrustmaster TX Steering wheel as non working.It's completely dead, not even the power indicator lights up.Many times the issue is with the optocoppler (FOD4216) activated by 5 (3.3V) from USB, which triggers a triac to open the circuit to the PCB.I bridged it, and this part of the power supply seems to work.What I have read so far the normal DC voltage are 25V.What surprises me is the fact, that my PS output reads 32V DC and more surprising as a negative voltage (no I haven't swapped the cable :-) ).Also I have realised, even disconnecting the power cable, the voltage stays quite a while, slowly falling.Unfortunately I haven't any external 25V power supply at my disposition.Any advice is very welcomed.
Under counter chiller compressor doesn't turn on. - Page 1
Forum section: electronics / repair

author: Yamin
author_rank: Frequent Contributor
timestamp: January 23, 2019, 08:17:47 am
content: Hi,Bit of a odd question here. I recently got a call to have a look at under counter chiller/ refrigerator which was not cooling. Someone else whose got a refrigeration background had a look and said that the compressor was not turning on - but it turns on only for once when ever the reset button of the controller is pressed. So he suspects that there is faults with the electronics.I haven't seen the unit myself the only information I have got its that the brand is Flomatic 2 door under counter chiller. I looked online and there wasn't much luck getting a service manual or schematic. (already requested the manufacture to get a copy)I was hoping that you could give some tips/advice on what look for. I would like to do my home-work before I goThanks so much
Looking for someone in the South East UK who can repair Arcade games - Page 1
Forum section: electronics / repair

author: CJay
author_rank: Super Contributor
timestamp: January 18, 2019, 03:30:46 pm
content: This may be a long shot but there's some cool geek points involved, there's a Vectrex Home arcade machine in need of repair in Brighton, the owner is looking for someone local who's interested in repairing it, it sounds like it has a monitor fault.He's also got a JAMMA arcade cab which needs repair, the fault description is a bit vague but it could well be a monitor fault too, sound is OK but the picture is unstable.He is looking for a local tech, not advice or tech help so they'd need to be reliable and able.I dearly wish I lived closer to him but Brighton is a *long* way, too far for a quick trip and I'd need to make two trips.
DVD Drive No Power - Page 1
Forum section: electronics / repair

author: vidarr
author_rank: Frequent Contributor
timestamp: January 20, 2019, 02:46:13 pm
content: I have a Pioneer DVR-XD09 writer external drive that just stopped working. It doesn't work plugged in solo USB, or with the 5v plug also plugged in. I opened it up and tested a few points and see 5v at a couple locations, but I have no idea what I am doing. I watched the videos of troubleshooting where you follow the power through the circuit and it seems to make sense the way he did it. For whatever reason, I can't translate that method to my situation. Is there something in particular I should check?Same time, I need to have any working drive. I have a drive from a laptop. It needs this cable to work on my desktop:https://www.newegg.com/Product/Product.aspx?Item=N82E16812270183I noticed that it only has a power and a ground going to the drive. I looked for a pinout and cannot find one. Does someone have a pinout that can share with me? Or know which two are the power/ground on the drive? I can take a PSU 6pin cord and connect it to a SATA plug modified (reversed the L) to fit on the dvd drive for the power.This drive I need right away. I can make this makeshift cord work until a "real" cord can get here.Thank You.

author: Nusa
author_rank: Super Contributor
timestamp: January 20, 2019, 04:17:47 pm
content: https://linustechtips.com/main/topic/544704-making-molex-into-sata-5v/Sata part is easy, no change.Note the pitch is different on the power side. Trying to mod a sata cable probably will not work.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 20, 2019, 07:31:27 pm
content: Based on that picture, I can chose one of the 5v and one of the ground pins correct? There are two of each. I am just going to solder the power wires directly to the drive.Thank You.
Need Help Identifying a Part - Page 1
Forum section: electronics / repair

author: willbanks
author_rank: Contributor
timestamp: January 17, 2019, 09:31:57 pm
content: Hey all, I don't post here much but I have run into a wall.I work at a local repair shop, and I was given a Casio AP620 piano. The velocity of some of the keys were off and some keys didnt respond at all. I eventually identified the problem as a broken connector for the flat ribbon cable. When I pinched the connector together, it worked normally again.There is a crack in the jack connector that is causing no contact to be made, so I figured all I would have to do is replace the 30 pin female jack. But for the life of me, I can't find one anywhere, as I expected it would be fairly common. I searched up things like "flat ribbon cable female 30 pin connector", but nothing came up that would work or fit the pinout.So what I am asking is does anyone know what a connector like this would be "properly" called? I figured I must not be typing in the right keywords. I attached two pictures of the connector, one has the latch on and the other has the latch off. It is through hole and has 30 pins. I also attached a picture which shows what the kind of cable is that is inserted into the connector.If you have any idea what this piece would be called or know where I could get one, it would be awesome if you could let me know. Thank you!

author: pbarton
author_rank: Frequent Contributor
timestamp: January 17, 2019, 10:11:45 pm
content: It's a Zero Insertion Force (ZIF) socket, through hole, vertical mounting with 30 contacts/pins. With some specific pitch.So search for "ZIF socket, 30 contacts, vertical"Molex make several versions of these.Available from your local distributer, etc.

author: willbanks
author_rank: Contributor
timestamp: January 17, 2019, 10:33:02 pm
content: thank you so much!

author: fzabkar
author_rank: Super Contributor
timestamp: January 17, 2019, 10:38:37 pm
content: Searching for FFC/FPC might help.
Identify MOSFET package - Page 1
Forum section: electronics / repair

author: HugoPT
author_rank: Contributor
timestamp: January 16, 2019, 07:03:00 pm
content: Hello folksCan someone help me identify this mosfet package?I need to replace it but I'm not sure what is the package of it?Thanks for your time

author: iRepairElectronics
author_rank: Contributor
timestamp: January 16, 2019, 07:15:24 pm
content: what is this from? Make, Model,...numbers on the part?

author: HugoPT
author_rank: Contributor
timestamp: January 17, 2019, 10:53:51 am
content: BingoThanks for your time bro

author: Armadillo
author_rank: Super Contributor
timestamp: January 17, 2019, 09:04:15 pm
content: Portugal Scored? What's UP? LOL!
Removing old conformal coating? - Page 1
Forum section: electronics / repair

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 16, 2019, 03:50:13 am
content: I have an old bit of HP gear that I am giving a spit polish (5005A Signature Multimeter) and the conformal coating/clear spray coating on the PCB's is looking a bit blegh and could to with a fresh application.I found when cleaning the boards with isopropyl alcohol that the coating started to go a bit tacky and in some places I could rub it off with a bit of effort.I'm wondering if there is any product that I could use to dissolve the coating somewhat easily but one that wont damage the silkscreen or components?Anyone have any suggestions to try?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 17, 2019, 02:40:10 am
content: Does that seem to be a clear, hard coating or that soft coating?I looked in the 5005A manual and I couldn't find the conformal coating listed, so determining what works might require experimentation.If it's the clear hard coating, then it might be acrylic. I have experience with Humiseal 1B73:http://www.humiseal.com/products/aerosol-products/1b73/But I have not used the remover:http://www.humiseal.com/products/strippers/st-1080/For my own boards I just use Rustoleum Crystal Clear Enamel. It's also acrylic based:https://www.rustoleum.com/product-catalog/consumer-brands/stops-rust/clear-enamelSomething similar may be available in Japan. Maybe at places like Doit or Homepic.

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 17, 2019, 05:25:59 am
content: It is a hard clear coating, I think a type of acrylic laquer.Isopropyl alcohol doesn't really touch it much, (the coating only gets a little tacky) but methanol does, except methanol also takes off the silkscreen too....Replacement coating is easy enough to find here in Japan, but I just gotta get the old stuff off first....

author: tru3533
author_rank: Regular Contributor
timestamp: January 17, 2019, 05:44:18 pm
content: Have you tried to find the glass transition temperature?The glass transition temperature is the temperature range where the polymer substrate changes from a rigid glassy material to a soft (not melted) material.Heating the board to around 100 degrees celsius works great in many cases. (boiling water)And then the substrate can be removed easily with a flat bamboo stick or similar.
Trying to boot an old HTC PDA... - Page 1
Forum section: electronics / repair

author: gaopegn
author_rank: Newbie
timestamp: January 16, 2019, 08:19:56 am
content: Hi guys.I have an HTC apache(xv6700) which contains very important informations, and now it refuse to boot.This happened 3 times before, and the main cause should be the battery, because the device is usually run with USB power, and every time the problem happens when AC power were removed for more than 2 months.Sometimes the red LED light on, or half-boot, and this time the red LED flash for 0.1 sec, and then silent.I used to charge it for a long time to solve the problem, but now after a whole day the battery is more than 4v and it still not boot.Also, it do not power on without battery and with USB, the red light will flash continuesly.There are some relevant cases online:http://www.tomsguide.com/forum/id-975549/htc-apache-6700-boot.htmlhttps://forum.xda-developers.com/showthread.php?t=309830I tried to block some of the 6 pins on battery, the PDA will have different light such as solid red, but no way to boot.Are there any way to trick the device to boot? I need imformations in it.Thank you.

author: Zaddy
author_rank: Newbie
timestamp: January 17, 2019, 10:59:08 am
content: Instead of repairing yourself I would recommend you check with the genuine service centre. Let them have their say. Seems they will have a solution for this.
Tenma 72-10495 power supply. Need a schematic.  - Page 1
Forum section: electronics / repair

author: neilw20
author_rank: Newbie
timestamp: January 17, 2019, 10:23:41 am
content: I accidently connected a battery the wrong way round and killed right hand channel, now shorted.It will be much easier to repair with a schematic. Anyone have a 'top secret' schematic or service manual?ThanksNeil.

author: Jeroen3
author_rank: Super Contributor
timestamp: January 17, 2019, 10:47:44 am
content: https://www.eevblog.com/forum/repair/korad-ka3005p-power-supply-calibration/msg1109803/#msg1109803
Plasma TV buzz - possible cracked transformer - Page 1
Forum section: electronics / repair

author: CrackedCore
author_rank: Newbie
timestamp: January 04, 2019, 03:43:29 pm
content: https://imgur.com/a/a65gzVNSeems like this is the loudest source of buzzingIs there anything i can do about it?Zip tie it? Nail polish or something like that?

author: eKretz
author_rank: Frequent Contributor
timestamp: January 04, 2019, 08:58:13 pm
content: Depending on temperature you might be able to use hot glue to secure it. Probably even epoxy since it's not in contact with the windings.

author: iRepairElectronics
author_rank: Contributor
timestamp: January 16, 2019, 05:37:18 pm
content: There should be a reason why its buzzing. possibly drawing too much current?I would check the solder joint on that bad boy.It looks like a panasonic board to me. What make and model is it?

author: Armadillo
author_rank: Super Contributor
timestamp: January 16, 2019, 09:33:49 pm
content: Hi, how are you sure it is from this transformer?I think the most likely culprit are those from the HV inverters transformers, yes /no?
So who's making the "good" 10K audio taper pot these days? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: January 15, 2019, 02:29:46 pm
content: Hi all-Re-doing a vintage mixing desk and want to find a quality replacement for 10K ohm audio taper single turn rotary pots. These are the main gain pot on the input modules - 3/8" mounting hole and 1/4" shaft.I'd like to go with conductive plastic if I can. I know the Bourns product line and they seem fine, but is there anything else I should be looking at?(Penny & Giles is long gone, correct?)Thanks.

author: drknob
author_rank: Contributor
timestamp: January 15, 2019, 02:59:41 pm
content: Check Alps:https://www.alps.com/prod/info/E/HTML/Potentiometer/RotaryPotentiometers/RotaryPotentiometers_list1.html

author: cncjerry
author_rank: Unknown
timestamp: January 16, 2019, 03:54:15 am
content: +1 on Alps.
Removing broken touch panel from Surface 3 LCD with heat gun? - Page 1
Forum section: electronics / repair

author: torini
author_rank: Newbie
timestamp: January 19, 2019, 10:01:02 pm
content: About 2 months ago I bought a damaged Surface 3 (not pro) to use with external monitor, kind of like a smart monitor, I was certain that the screen was completely gone because the touch panel was pretty beat up (even the body of the tablet is bent at one corner) Today I connected it up just for the heck of it and what do you know, the LCD itself is perfectly fine. So I want to remove the damaged touch panel and use the tablet with the original screen instead of external monitor, but its pretty tightly glued to the screen. I want to know if using a heat gun on it to loosen the glue would be fine or not? And how much heat could it take before damaging it? There doesn't seem to be any gap between the two, is this what they call a laminated screen?

author: Jeroen3
author_rank: Super Contributor
timestamp: January 19, 2019, 10:18:01 pm
content: I don't think this is possible without specialised equipment.
Astec LPQ154 PSU out of R&S SML01 signal gen., high frequency ripple! - Page 1
Forum section: electronics / repair

author: alpher
author_rank: Frequent Contributor
timestamp: January 16, 2019, 04:14:24 pm
content: Hi, I've got this R&S sml01 signal gen. on the bench, it came with flickering LCD and supposedly bad attenuator.Powered it on and sure enough unit seems to be working but the LCD display flickers quite badly, so before doing anything else I decided to check the psu.It's a separate 4 output Astec LPQ154 modular unit, i've attached a specs sheet for it. Measured voltages are fine5V,12V,-12V and 24V all within specs but, when I hooked up scope to the 5V output the ripple was just over the top.With the psu running inside R&S sig. gen. the noise on 5V line was ~4Vpp !.When i removed the psu from the generator, hooked up on the bench with a resistive loads on the outputs (1, 12, 12, and 24respectively) the ripple on 5V line came to be ~900mVpp, on 12V lines ~1.7Vpp similiar on 24V line.Here are a cople of screenshoots from my scope:5V loadded @5A :and here 12V line loadded 1A:Now normaly I don't repair PSUs, have very limited experience with these, but what I noticed is that it seems to be rather high quality unit, electrolytic caps are all Nichicons, there is no leaked electrolyte no bulging and meassured with my Peak ESR meter all the caps seem to be OK ( granted I meassured in circuit) ESR < 0.1.Before I blindly start changing the caps, I wonder if there's something obvious that I don't know?What may cause the excessive high frequency noise on all of the outputs at the same time?Could it be something on the primary side of the transformer? or may a shorted diode somewhere in circuit cause these symptoms?As I said I have little to none experience with the se switching PSUs, especially this one.Seems way overengineered to me, schematic not available of course (at least I couldn't find one),here are some pics of it:Any pointers?

author: Armadillo
author_rank: Super Contributor
timestamp: January 16, 2019, 04:39:44 pm
content: Yoo!, I don't think that is ripple, it's RF feed thru or simply RF noise. With the casing open, it can propagate everywhere.What is the BW of the oscilloscope you set? Limit it to 20MHz and try again, yes / no?

author: alpher
author_rank: Frequent Contributor
timestamp: January 16, 2019, 04:48:15 pm
content: Thanks, the bandwith was full 100mhz, will measure tonight with 20Mhz limit, but at first when measured wth the cover on inside the generator noise was even higher.?What gives, it's suppossed to be a high quality unit, I don't think that even with the cover removed this amount of noise is normal?
Help identifying component SOT-23 - Page 1
Forum section: electronics / repair

author: jerb
author_rank: Contributor
timestamp: January 15, 2019, 02:02:58 pm
content: Have a SOT-23-3 Transistor that has the markings LP on the top of it. Nothing else. I need a replacement but i cannot find any information at all on it. Any help would be greatly appreciated. I want to think it's a voltage sensing transistor but i'm not sure.

author: Armadillo
author_rank: Super Contributor
timestamp: January 15, 2019, 02:09:09 pm
content: Try RT9169

author: jerb
author_rank: Contributor
timestamp: January 15, 2019, 07:42:38 pm
content: Wow that's one awesome regulator. The range on it looks promising. I guess i should have been less ambiguous but this part is for a gtx 1080 ti gpu. I'll see if i can find one and get it in. I've been looking all day on any donor parts, camera, motherboards, other gpus. But i just haven't been able to find one dimension wise that matches. I don't know how to tell the name difference between the slightly smaller and larger sot23 packages.edit: I've attached a photo of the area that the chip came off of.
Does IT8528E I/O chip require programming before use? - Page 1
Forum section: electronics / repair

author: torini
author_rank: Newbie
timestamp: January 14, 2019, 03:19:14 pm
content: Need to replace one of these chips, does it need to be programmed?

author: khaahk
author_rank: Contributor
timestamp: January 14, 2019, 06:03:41 pm
content: No

author: amyk
author_rank: Super Contributor
timestamp: January 15, 2019, 03:44:52 am
content: Quote from: khaahk on January 14, 2019, 06:03:41 pmDo you have a datasheet?Some of the ITE ECs share the same flash as the BIOS, others have their own internal flash.

author: fzabkar
author_rank: Super Contributor
timestamp: January 15, 2019, 04:40:50 am
content: It's not a datasheet, but it might help you to work out whether it has any flash.http://datasheetcafe.databank.netdna-cdn.com/wp-content/uploads/2015/09/IT8528E.pdfFrom the block diagram, it would appear that the "SPI ROM 4MB (BIOS/EC)" is external.
KRK Rokit 6 No Output - Page 1
Forum section: electronics / repair

author: Robin
author_rank: Contributor
timestamp: January 11, 2019, 08:17:49 pm
content: Hi guys,I have a KRK Rokit 6 on repair at the moment. The speaker turns on fine, but no sound is coming from the drivers.To start off, both sub and tweeter are fine.There is no DC on the outputsThe amplifier board uses two amplifier IC's. The TDA5052 for the HF and the TDA7492 for the LF. Just like the one in Dave's video it also HAD the black gunk but that's all cleanly removed and main capacitors and affected resistors are replaced.This is what I'm measuring. Everything on the power amplifier board seams to be fine. The reason why there is no output is that there is -19.25VDC (negative rail) on the MUTE pin of both amplifier IC's. To unmute it, it should be a positive voltage. The negative voltage comes from a comparator ic on the input/filter/limiter board. Which singals it compares, I don't know.Does someone have a suggestion on why the output of that comparator is pulled low?

author: Robin
author_rank: Contributor
timestamp: January 14, 2019, 08:21:39 pm
content: FIXED!The culprit was indeed that comparator. It was a JRC4580D and the only opamp I got laying around was a LM358, but the pinout matched so I threw it in. Now it works like a charm with a positive output as mute signal.
TTi CPX 200 Dual 35V PSU - schematic? - Page 1
Forum section: electronics / repair

author: John C
author_rank: Newbie
timestamp: January 14, 2019, 07:00:03 pm
content: On the off-chance, anyone got a schematic, or even service manual they could share? My venerable old friend has developed a fault - one half struggles to start up - all displays and LEDs flickering - won't stay on (spikes when o/p switch hit). Clears after a few seconds then clean happy o/p , but taking longer - so something deteriorating. Schematic would be a big help. Many thanks in advance!

author: JFJ
author_rank: Regular Contributor
timestamp: January 14, 2019, 08:17:41 pm
content: The TTi CPX200 service manual is too big to post on the forum, but it can be downloaded from here:http://w.ko4bb.com/getsimple/index.php?id=download&file=06_Misc_Test_Equipment/Thurlby_TTi/TTi_CPX200_Power_Supply_Service_Manual.pdf
Samsung LE40A616 LCD problem - Page 1
Forum section: electronics / repair

author: T-5
author_rank: Newbie
timestamp: January 14, 2019, 12:41:05 pm
content: Hi there!I found a Samsung LE40A616A3F in the dumpster. The problem with it is that portions of the screen are very slow to update and show a lot os smearing. To me (not very experienced with problems like this) it looks as if the driving current/voltages to the LCD transistors are not strong enough, maybe a power supply issue? But see for yourself, I made a video:https://t-5.eu/owncloud/index.php/s/ZqM43h4KW7nxDlsIs it repairable?Thanks in advance!Jürgen

author: Armadillo
author_rank: Super Contributor
timestamp: January 14, 2019, 01:06:20 pm
content: Defective LCD Panel.

author: T-5
author_rank: Newbie
timestamp: January 14, 2019, 05:30:14 pm
content: how sure are you? inpercent?

author: Armadillo
author_rank: Super Contributor
timestamp: January 14, 2019, 05:33:05 pm
content: 100%.ONE HUNDRED PERCENT.

author: T-5
author_rank: Newbie
timestamp: January 14, 2019, 06:47:31 pm
content: Thank you very much for your input!
Repair an AMD R9 380 4GB Graphics Card - Page 1
Forum section: electronics / repair

author: iRonNuke
author_rank: Newbie
timestamp: January 12, 2019, 07:12:10 pm
content: Hi I have a completly dead GPU (Sapphire AMD R9 380). No fans spinning, no display out or recognized by computer.Now I think I found a problem with it. A resistor(?) at PCIe bus seems to be dead. See picture for more. How do I find what type of component this is?Thanks!

author: wraper
author_rank: Unknown
timestamp: January 12, 2019, 07:15:03 pm
content: What do you mean by dead? Looks like polyfuse (resettable fuse), it should have low resistance, almost shorted.

author: iRonNuke
author_rank: Newbie
timestamp: January 12, 2019, 08:08:34 pm
content: I removed the heatsink and fan and did a testrun. The GPU itself it's getting lukewarm. Memory cold. Got 12V (and 3.3V) at some points so it isn't completely dead.Is that component at the attached picture a polyfuse? When I measured the resistance over that component it was an interruption.

author: DaJMasta
author_rank: Super Contributor
timestamp: January 12, 2019, 08:39:36 pm
content: An interruption? A short? It should read as a short or nearly a short for normal operation.Not recognized by the computer at all is definitely pcie interface related, but I think on modern cards that's all straight into the GPU. While there could be a little bit in between it, the GPU is either not fully powering up (power component fault) or is the fault itself.

author: iRonNuke
author_rank: Newbie
timestamp: January 12, 2019, 08:43:29 pm
content: Yes an interuption. I bridged the component but still no go. Didn't test out if the GPU as getting warm before that procedure due.Do you guys know any particular places to measure on this PCB?More information is that I think it got really hot before (or during) it died. Seems that some liquid (from the solder?) has flowed over the PCB at some places, like at the VRAM and around the PCIe slot.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 14, 2019, 05:47:33 pm
content: Quote from: iRonNuke on January 12, 2019, 08:43:29 pmSorry for the cardIt really is not good idea to short a fuse as fuse broke for a reason (there was some other problem that caused too high current flow)Fuse blew in attempt to protect further damage and bridging it can lead to this damage.Any case what is done is done.I would think the most common faults will be GPU VRAM and if these are done card is done as it is not feasible or cost efficient to replace those components most of times.Voltage regulators can also become faulty maybe someone can help further.Best of luck !
Frozen DS1054Z on startup - Page 1
Forum section: electronics / repair

author: Rbastler
author_rank: Frequent Contributor
timestamp: January 12, 2019, 12:18:07 pm
content: The other day I switched my DS1054Z on and it copletely froze on startup. The front panel didn`t work at all, but the scope itself was working with the Ultra Sigma software.Thats also was what I used to push the scope out of that frozen mode to first do a factory reset and then a firmware update. After that, it seems to work fine again. All I did was to click random buttons on the Ultra Sigma software and it worked again briefly. Switching channels and doing Autoset seemd to do bring the frontpanel back.Without that, no factory reset whatsoever worked.Maybe this helps somebody else, who has the same problem as I do and nothing else works.

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: January 14, 2019, 12:33:57 am
content: see you
Agilent U1252A multimeter - Page 1
Forum section: electronics / repair

author: Tharkun
author_rank: Newbie
timestamp: January 13, 2019, 12:31:19 pm
content: I have an Agilent U1252A multimeter. All functions seem to work as expected except DC volts which shows 0.0000V no matter what the applied voltage is. Ac volts is fine, as is dc millivolts, and the frequency counter, ohmmeter etc.I tried the obvious stuff like fuses, they all checkout fine, can’t see anything obviously wrong like dry joints, bridged or disconnected tracks, bulging or leaking caps, or burnt stuff.I can’t seem to get hold of the circuit diagram, which makes going further difficult.Where do I go from here, maybe someone has had this kind of fault before. Maybe someone can give me a rough indication of the path I should check, I’m guessing, most multimeters, have input protection, followed by scaling and ranging, then a to d conversion and comparison against an accurate reference, and display.Any hints anyone?Tim

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 13, 2019, 06:42:04 pm
content: You have done a lot of work and your guesses are right.You can try this:0. Give as pictures of the device and board.1. If the DC voltage is the only thing thats not working then the supplied voltage to the measuring IC is "0VDC", its not possible to receive "0VDC", it should be something like "0.001VDC". Can you check with a second multimeter the line for the "VDC" voltage measuring from the display to the input. The display should be supplied with the number from some IC, which is directly measuring or is connected to the measuring one.( I don't mean to offend you but it would be good to see how you measure and what is your "VDC" voltage source).
Simpler networks mini pass through adaptor - Page 1
Forum section: electronics / repair

author: Specmaster
author_rank: Super Contributor
timestamp: January 13, 2019, 12:29:35 pm
content: Has anyone worked on these 13A WiFi adaptors that pass network via mains system at all?I have one that stopped working and had a rattle inside it but I can't seem to open it up. Removed screws bug still no access to insides?