hybridfree/eevblog-posts huggingface dataset:
Removing Flux - Page 1
Forum section: electronics / beginners

author: dcbrown73
author_rank: Regular Contributor
timestamp: July 01, 2019, 01:13:31 pm
content: Hello,I've recently been buying cheap kits to practice on my soldering skills. While many I only used to practice, some I want to keep. (like substitution boxes) and so I went about trying to remove the flux left from soldering.What is the preferred method as I read different things from different people. I purchased MG Chemicals 413B in a spray can and while it removed the bulk of the left over flux, there is still a thin sticky film left.I also have some 99% Isopropyl alcohol that I use for cleaning other things, but those I usually submerge in the alcohol. That seems to do a better job than spraying the MB 413 and using a static free brush. Maybe if the MG 413 wasn't a spray can and I could submerge it in that.Should I just switch to the alcohol or am I just using the MG 413 incorrectly? I suppose the alcohol is less dangerous of a chemical.Thanks for any feedback.

author: Shock
author_rank: Super Contributor
timestamp: July 01, 2019, 01:42:41 pm
content: You are probably just seeing flux residue. It becomes dissolved in the solvent and once the solvent evaporates it remains distributed everywhere the solvent was.So keep your scrub stage to loosen up and dissolve the flux and add a couple of rinse stages in cleaning or spray it down so the flux can run off with the solvent. If you have problems you can contact the solder/flux manufacturer and see what they recommend or change brands. Remember to use ventilation and fume extraction especially with flux cleaners and non rosin fluxes that have god knows what in them.As I mentioned in another thread recently, start with as pure IPA as you can get and then cut it down with deionized water, if you need something more aggressive you can make up an IPA or deionized water cleaning solution with an electronics safe detergent or more aggressive solvent. Finally rinse in deionized water or IPA. This is essentially what is done in production.

author: radiolistener
author_rank: Super Contributor
timestamp: July 01, 2019, 01:48:45 pm
content: I think ethanol (also known as alcohol) is the best way.I'm using 96% ethanol (C2H6O) and it works great.Rinse your board in the ethanol for some seconds and then use cotton wool and toothbrush moisturized in ethanol to remove flux. Then rinse it in the ethanol again and clean it with cotton wool moisturized in ethanol.Then put it on the air for a minute to dry out and that's itThe good thing is that ethanol is not toxic, so there is no need to use safety glasses, gloves and gas mask

author: SteveyG
author_rank: Unknown
timestamp: July 01, 2019, 01:51:51 pm
content: Chemtronics Fluxclene makes short work of it, requiring very little scrubbing
Removing glue - Solvents & Suggestions - Page 1
Forum section: electronics / beginners

author: CkRtech
author_rank: Regular Contributor
timestamp: December 15, 2014, 09:36:54 pm
content: Hey all -Recapping a Samsung monitor's power supply board. Need to clean the glue off the PCB. Rubbing alcohol not really helping much. Up for suggestions.EX:

author: DmitryL
author_rank: Regular Contributor
timestamp: December 15, 2014, 09:39:44 pm
content: sidecutters; just cut it off

author: Leiothrix
author_rank: Regular Contributor
timestamp: December 15, 2014, 09:48:21 pm
content: Acetone.Side cutters probably easiest in that case though.

author: CkRtech
author_rank: Regular Contributor
timestamp: December 15, 2014, 10:08:55 pm
content: Thanks guys.Another one of my concerns with this glue (I am trying to remove as much as possible) -

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2014, 07:29:44 am
content: Freezer spray then simply crack it off when cold. The glue becomes brittle when cold. On the capacitor just use side cutters to pop it off the board and capacitor when frozen.

author: ExtremHybrid
author_rank: Newbie
timestamp: December 17, 2014, 03:43:16 pm
content: I personally like to use freezing spray and a cutter or even a hot-gun and then just peal things off with a paper towel and my fingers, before I resort to using Aceton.Aceton is really nasty stuff on multiple levels.It gets the job done very well, but it also can mess with other components your board, paint, markings, etc.If you have to get everything clean you just have to cut the components free from each other and then desolder them and then continue to clean every component with aceton and isopropyl alcohol (better for fats and greece than glues).Cleaning Bezin is also an option for some cases.It's good to have all three chemicals available in small quantities in little dispensers on your workbench.A box with q-tips and pre-cut papertowle (into 4 pieces) is also handy for clean up work.

author: CkRtech
author_rank: Regular Contributor
timestamp: December 24, 2014, 10:35:23 pm
content: Just wanted to hop back in here and thank everyone once again for their suggestions. I recapped the power supply (minus the large, 450v cap) and got the monitor working again. It takes awhile to "warm up" due to cutting in and out on first power up in the morning, but it functions the rest of the day. Perhaps I need to consider replacing some more components or doing a better job cleaning the glue off.Anyway - thanks again!
Removing glued(?) IC - Page 1
Forum section: electronics / beginners

author: olewales
author_rank: Regular Contributor
timestamp: April 11, 2016, 01:41:47 am
content: Hello, I need some practical advice.I am trying to remove damaged IC from PCB, but it seems to be glued to the PCB. It'sthis device. In the pin diagram (page 17) there is a pad in the center but it is not a large package and even though I am practically touching it with hot air nozzle blowing at 400degC I cannot get it to move. How do you usually approach this? I was trying to be neat but honestly I don't care if I damage the pads - I won't be replacing the IC. (just trying to repair the router. IC is running hot, loading 3.3V rail and not working anyways. I can disable this PHY when building new firmware). Should I just cut the traces around and not bother with desoldering anymore?

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: April 11, 2016, 02:27:04 am
content: If it's got a center pad, it's likely not glued. A hint that parts are glued is to look for nearby passives, if you can see the (usually red) glue underneath, then the other parts may be glued as well.Most likely you're not applying enough heat to the part. The EPAD will be soldered to the ground plane, which is drawing heat away from the IC. Just keep at it for a while, maybe at a slightly lower temperature than 400 C. When the board is nicely heated up, ramp up the temperature and focus the hot air on the IC alone.

author: KL27x
author_rank: Super Contributor
timestamp: April 11, 2016, 02:38:21 am
content: QuoteTurn the temp and/or airflow up. I've turned mine up to 480 for a small chip. It is very dependent on the board/pour.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 11, 2016, 04:24:04 am
content: Your data sheet shows that chip has a GIGANTIC thermal/ground pad on the bottom. Even if you could successfully detach ALL the pins around the edge, you would still have a very challenging task removing the chip without damage to the PC board and/or adjacent components.If the chip is really dead and must be removed, you could cut off all the legs from the package with a hobby knife. Then you could pretty easily de-solder/remove them individually.

author: olewales
author_rank: Regular Contributor
timestamp: April 11, 2016, 02:04:33 pm
content: I MADE IT! You were right, it was not glue. Just a soldered ground padI know that swearing is not very professional but... fucking hell. This was a nightmare.I was a bit skeptical about what Richard said, I mean: this is a 7x7mm part. How hard can that be?!Well, it took 40W iron @400deg heating PCB ground pad from the bottom (was looking at PSU current so I know it actually delivered about that much power) and hot air on the top at the same time. And even then it took quite some time and still needed to gently pry chip off with tweezers.I know about thermal mass but I'd never think that this pad could conduct so much heat out so that IC so small could resist hot air gun. Well, it's never late to learn.Thank you all for responses guys!
Removing goofed-up silk screen from pads - Page 1
Forum section: electronics / beginners

author: FlashEF
author_rank: Contributor
timestamp: October 08, 2012, 09:09:17 am
content: Hi,I've forgot to turn on silk screen over pads checking before sending my board to production, and was totally blinded for several lines crossing my pads. My question is how to best attempt to repair this. First idea is to cut the silk screen material on the edges of the pad with a razor blade and attempt to lift it by melting tin underneath. Luckily I've ordered thick tin plating. Before I do that I'd prefer to hear your ideas. This board is quite important and it would be good to save it.How it looks like:http://img.photobucket.com/albums/v508/Flash_EF/SilkProblem.jpg

author: AndyC_772
author_rank: Super Contributor
timestamp: October 08, 2012, 10:47:16 am
content: Oops! We've all done it, though many PCB vendors will automatically mask out any silk screen that overlaps exposed copper pads. It might be worth adding a note to your drill drawing to require vendors to do this for you in future.Are you going to solder the board straight away? If so then it doesn't matter too much if you remove some of the surface plating in the process of removing the silkscreen, as its main purpose is to prevent oxidation.I'd start with a fibreglass pencil, or possibly just scratch it away with a sharp scalpel. Shouldn't be too hard IMHO.

author: FlashEF
author_rank: Contributor
timestamp: October 09, 2012, 03:06:46 pm
content: Thank you for your replays. I'll post a photo when it gets cleaned and comment how it went.

author: FlashEF
author_rank: Contributor
timestamp: October 13, 2012, 07:49:11 pm
content: Not really worth a photo. The silk screen material scrapes clean of the pads - it seems to be unable to stick to metal. So - for anyone who does that mistake in the future - it can be removed with any any sharp object.
Removing hard-to-reach solder bridge? - Page 1
Forum section: electronics / beginners

author: pcee
author_rank: Regular Contributor
timestamp: September 12, 2021, 01:52:03 am
content: I’m no expert at soldering, but I find myself needing to solder wires to a 1.27mm pitch connector with solder cups.I’ve got 0.4mm 63/37 solder for the job, and it’s fine enough I think, but I still managed to use a little too much on one pin and some solder ended up bridging two pins. (Lesson learned: use some kapton tape to hedge against my clumsiness.)The gap between pins is only 0.25mm, so I’m having a hard time coaxing the solder out with wick. I could try some finer solder wick than I currently have, but the smallest I’ve seen is 0.8mm wide (not sure of thickness), so I don’t know whether I can get that between the pins.But is that even the right approach? All of the tips I’ve seen on fixing solder bridges have been along a row of SMD pins, but these pins are cylindrical, and the solder bridge isn’t simply sitting on the surface as with SMD.What should I try to get the solder out from such a tight space?

author: jmelson
author_rank: Super Contributor
timestamp: September 12, 2021, 02:08:47 am
content: If the wick won't work, apply MORE solder, then wick it all back up again. That's my technique. If you have liquid rosin flux, you can apply some of that to helpthe solder wet to the pads.I do this on 0.5 and even 0.4mm lead pitch chips all the time. A microscope helps to see what you are doing.Jon

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: September 12, 2021, 02:47:44 am
content: If your braid is too big twist up some thin stranded wire and dip it in flux.

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2021, 03:33:42 am
content: Sometimes it works to just add some flux and heat one of the pins.

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 12, 2021, 04:10:10 pm
content: A flux or a flux and a toothpick.

author: OldEE
author_rank: Contributor
timestamp: September 12, 2021, 04:21:18 pm
content: Heat up the recalcitrant pins, with a little extra solder if needed, and tap the connector on a hard surface such as piece of wood. The solder will come flying off.Usual warnings about flying molten solder so beware of your surroundings and where the solder might go. Use safety glasses!Been doing this for decades and it really works well if you are careful.Larry

author: Renate
author_rank: Super Contributor
timestamp: September 12, 2021, 07:13:35 pm
content: If you really want to make a mess and you have, say, 100 tube sockets to clean up.Use solder and an iron to heat it up then hit it with a 60 PSI air gun.When you're through, clean the walls.(I have actually done this.)
Removing negative spikes selectively - Page 1
Forum section: electronics / beginners

author: Thomashoej
author_rank: Newbie
timestamp: March 14, 2022, 05:14:27 pm
content: Hi,So i am working on a rev limiter for my mopedIn order to limit the revs, I need to remove the spark, which is done by shorting the negative signal from the pickup (a coil that essentially pulses at a specific point on every rotation). I've probed it and screenshot it, on my first attachmentMy problem is, that I have no idea how I can remove the negative signal...I though about using a transistor, but it turns out that it isn't too happy with -12v from collector to emitter.i would've used a relay, but they are too slow. the signal will be repeating at every 4.5 ms.does anyone have an idea to remove the negative signal, like on my second attachment (I manually connected a diode, to show what I wish for it to do)?

author: Terry Bites
author_rank: Super Contributor
timestamp: March 14, 2022, 06:47:01 pm
content: A suitably rated diode with a series resistor should do it. You could add a comparator- this will ignore the negative part of the waveform completely.eg
Removing noise spikes generated by fan  - Page 1
Forum section: electronics / beginners

author: Kevin.D
author_rank: Frequent Contributor
timestamp: January 02, 2013, 09:47:44 pm
content: Hi guys .I am buiding a project and I am using standard pc cpu fans in it ,they are generating noise on my power lines and I need to get rid of it .They are the 3 wire fans with the tacho output ,I am NOT using the tacho output ,just leaving it unconnected.When using them The fans I have here are generating whatLooks like bursts of 3 MHz noise pulses at the frequency of the fan ,each packet last about .1 mS they are about 200mV - 400mV p-p .Looks like there is some other very minor noise present to.How to get rid of it .?Thanks in advance

author: AndyC_772
author_rank: Super Contributor
timestamp: January 02, 2013, 11:11:55 pm
content: A 10uF ceramic capacitor connected directly across the fan's leads at the point where they connect to your board should help a lot, if you don't have one already.If that doesn't help, look carefully at your layout. Can you post a photo of your board showing exactly where the fan's leads attach to it?

author: SeanB
author_rank: Super Contributor
timestamp: January 03, 2013, 04:56:35 am
content: 100uF low ESR cap, 10R 0.5W resistor and another 100uF low ESR cap after it, both with a 100n chip ceranic across them. negative lead to go to the capacitor pad and then to the first capacitor pad, then connect to the ground plane.

author: Kremmen
author_rank: Super Contributor
timestamp: January 03, 2013, 03:26:45 pm
content: Or you might go as far as threading the fan wires through a ferrite bead?

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 03, 2013, 03:43:40 pm
content: QuoteI'd start by throwing out the fan, it should not behave like an AWG.

author: ciccio
author_rank: Frequent Contributor
timestamp: January 03, 2013, 08:59:36 pm
content: Quote from: SeanB on January 03, 2013, 04:56:35 amI've discovered that different model of fans, even from the same manufacturer, have different noise (more than 20 dB difference between two 24 V, 80 x 80 x 25 mm fans from a top-rated Company (SunOn)).SeanB' proposal works well, but I prefer to power the fan from unregulated DC, before voltage regulation, with an appropriate series resistor (to get the correct voltage across the fan) and a BIG electrolytic capacitor in parallel with the fan. The negative wire must be connected to ground at a suitable point, to be found by experiment, usually near the negative pin of the main supply's filter capacitor.Noise seem to increase with current, so using an higher voltage fan sometimes helps.My preferred solution (with dual rail supplies) is to power the fan from positive unregulated DC to negative unregulated DC, with two suitable series resistors, a big electrolytic in parallel with the fan. No connection to circuit ground.Typical values (from +/- 24 V dc unregulated) are two 330 ohms / 2W resistor and a 470 uF capacitor, resulting in about 15 V driving a 24 V fan at a lower than nominal speed.Best regards.
Removing the shielding from individual wires in USB3 cable - Page 1
Forum section: electronics / beginners

author: tchicago
author_rank: Regular Contributor
timestamp: January 16, 2022, 07:54:40 pm
content: Hello, all,I'm looking for some advice on how to remove the plastic/foil shielding wrap from the individual pairs in the multipair high frequency cables like USB3.I cut that wire and needed to solder it to something else, and found that the shielding is extremely tight and hard to remove. I managed to remove it from the pairs by slicing Xacto knife between the pairs, which is still hard to do without damaging the wires inside.But the removing the shielding from the individual wires seems nearly impossible. They are marked with red arrows on the photo. Tried heating hem with heatgun with a variety of temperatures, but the shielding does not soften nor unglues.Does anyone know how to do this? Tried googling/youtubing it, found nothing. There *should* be some easy way for those who assemble such cables and solder them.

author: kleinPE
author_rank: Newbie
timestamp: January 16, 2022, 11:05:00 pm
content: if heat does not help what about taping it into a shotglas and filling it with aceton, so the tips should melt away after a few hours.and sorry that i have to ask: have you tried using de-isolation pliers(google: abisolierzange)? but if the wire is small and tough you might want to get the manual ones.but dont cheap out, because the cheap ones have too much play in them and only bend the wires instead of cutting away the isolation.if its just 1 cable you might want to ask an electrician if you know one.edit: such tiny wires usually dont get soldered. the connectors into which they are pressed have tiny blades in them, which cut through the isolation without removing it. and the contact is then creatd by the blades.

author: tchicago
author_rank: Regular Contributor
timestamp: January 17, 2022, 02:33:18 am
content: Thanks for the replies! The solvents don't help. Tried isopropyl alcohol and acetone.The wire strippers also don't help because they take the overwrap together with the insulation of the wire, leaving the bare wire dangerously close to the grounded foil. Not good.After careful inspection under the microscope I found that it is indeed a wrapping, and if I can find a tiny corner of the wrap at the end, then I can lift it and then grab with the whole wire or pair between fingers, and slowly undo it in clockwise motion. This lifts the foil wrap from the pair of wires. The foil is actually a band 6-7mm wide wrapped at an angle in a clockwise direction. However each differential pair is then wrapped in in another layer of plastic, and in opposite counterclockwise direction. So I again need to find a tiny tip of that plastic wrap, lift it with something sharp and then twist with fingers to slowly unwrap it. At the end, the whole cable took about 30 minutes to free up each individual wire in its own plastic isolation. 4 pairs total and 4 individual wires.It is a very labor intensive work indeed.
Renaming Bluetooth module KRC-86B - Page 1
Forum section: electronics / beginners

author: vindoline
author_rank: Unknown
timestamp: March 17, 2016, 04:59:57 am
content: I recently got an inexpensive bluetooth audio module from everyone's favorite auction site with the thought of adding streaming audio to a table radio of mine. I bought a KRC-86B v4.0. For example see:http://www.ebay.com/itm/DIY-Module-KRC-86B-Bluetooth-4-0-Stereo-Audio-Receiver-Module-Speaker-Amplifier-/162005290326?hash=item25b8448d56:g:gcwAAOSwG-1W1AtKSurprisingly, it was a perfectly smooth hack to get up and running!My question is that the module appears as "KRC-86B V4.0" I'd rather it say something like "kitchen radio", especially if I mod several radios. They will all show up as "KRC-86B"! I can't find a data sheet or any real technical documentation on this board on the net. Does anyone know how to change the default name?thanks,John

author: Apollo
author_rank: Newbie
timestamp: February 04, 2019, 08:50:55 pm
content: Hi John, did you ever find a solution to re-naming the KRC-86B? I have a couple of these and would like to do the same.ThanksMike

author: vindoline
author_rank: Unknown
timestamp: February 04, 2019, 10:21:10 pm
content: Hi. Unfortunately, no. I ended up buying some different modules from here:https://www.tinyosshop.com/index.php?route=product/product&product_id=875They even have a page on specifically how to change the Bluetooth name. I ended up spending quite a bit more than I wanted to.Good luck! Let us know if you find an easy, cheap solution.-John

author: Apollo
author_rank: Newbie
timestamp: February 05, 2019, 08:10:08 am
content: Thanks John, looks like a nice little alternative, but am reluctant to buy the necessary bits just to change the name...Will let you know if I come across a solutionThanksMike

author: tooki
author_rank: Super Contributor
timestamp: February 06, 2019, 04:56:42 pm
content: Googling for 3 mins to find a decent quality pic of the board got me the part number of the bluetooth IC, and googling the part number autosuggested "csr8630 programming", and the very first hit is an instructable on how to reprogram it:https://www.instructables.com/id/CSR-Bluetooth-Module-Programming/
Renesas HS8/2134A need to read - Page 1
Forum section: electronics / beginners

author: james101
author_rank: Contributor
timestamp: May 28, 2022, 06:43:39 am
content: Hi guys just wondering if anyone can help us out with this issuesgot the following chip it working for nowbut i like to do a backup file of itbut its not unlockedwould glitching help and bypass the protection so i can copy itanyone know of a programmer that can read this type of locked chipsand recommend one to us.microprocessor Type Renesas HS8/2134Atried the orange 5 from china which of course is some type of copy does not list iton the programmer.but does the real orange 5 programmer cover this chip.can anyone check for us.thank you
Renewable Energy - Page 1
Forum section: electronics / beginners

author: ToeJam
author_rank: Contributor
timestamp: October 10, 2014, 09:03:51 pm
content: O0Hey Dave & everyone else;This guy has quite a PV system going on.Could be worth quite a trip north to have a look and interview the guy maybe?I remember seeing a video of PV being installed on your home roof Dave, and I've just bought my first battery for my own power backup system.Scotland doesn't get much solar exposure tho. Soaked through, Hydro is a better bet.Cheers mateThanks for all the great videosKeithScottish Borderswww.youtube.com/channel/UC0Z4oQ-buX7qb4teb0TRtWQ
Renu FlexPanels Tutorial Required - Page 1
Forum section: electronics / beginners

author: aju11
author_rank: Contributor
timestamp: September 03, 2019, 05:42:23 am
content: Hello,I have been assigned to work onRenu FlexiPanel HMIfor a project.Project Details:Interface Three 0-10V flow sensors, display Flow data on HMI screen, configure set-points via touch screen, control three proportional valves by PID.Renu FlexiPanel HMI has options to connect Analog Input and output cards.I am do not have any experience with plc/HMI programming.Is there a programming tutorial available for this plc?I tried Youtubehttps://www.youtube.com/channel/UCMNaPHG8qYKok0XEcDAWXeABut this has limited information.
ReoLink CCTV repair or scrap? - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: March 03, 2021, 01:00:35 pm
content: Friend passed me a Reolink CCTV hub. He bought it second hand and it didn't power up. It's 48V supply is fine and it has 12V and 5V on the SATA power cable. There is no 5V on the USB or HDMI.I traced 5V across the board to a single transistor when it dropped to 0.050V. However when I put the thermal camera on it I noticed the 8 pin IC providing the 5V power was smolderingly hot. Like over 125*C.Measuring the 5V close to the inductor for the regulator shows the voltage unstable and there are signs the chip is burning through.Without knowing what caused the switch regulator chip to go Nova, is there any long-shot salvage value in removing the inductor and soldering a linear 7805 to inject 5V from the 12V line into the circuit where 5V was supposed to be?I expect whatever caused the 5V rail to fail will just cause the new hacked one to fail.
repair advice (machine was never grounded) - Page 1
Forum section: electronics / beginners

author: algorithm
author_rank: Regular Contributor
timestamp: August 02, 2014, 07:25:57 am
content: I got this japanese electronic, I have many japanese electronics running on 120v just dandy normally.This 1 in particular, seemed to progressively get worse the longer it was plugged in.1 terrible flaw with this specific piece is there is no fuse.also, the machine required a ground, but there are not ground slots in japan normally.I know definitely this piece was used without grounding it ever before it got to the states. I received it with a little adaptor to bypass ground from the previous owner.It had a problem when it was purchased, but it got worse and worse.It has a panel of buttons with a display, and the buttons trigger randomly and sporadically, LEDs seem to go out and come on regardless of button presses...What would happen if something was run for nearly 20+ years without it grounded?& Then was grounded while powered after all that?Thanks ahead of time!

author: SeanB
author_rank: Super Contributor
timestamp: August 02, 2014, 06:00:18 pm
content: If it is grounded now the problem is likely unrelated, unless the socket outlet itself is faulty and is not actually grounded.Likely the power supply capacitors are showing age and gradually failing and need to be replaced. This causes extra ripple on the supply rails and will give symptoms like you describe with digital selection of inputs and such. Open it up, post some pictures and it is likely an easy repair.

author: algorithm
author_rank: Regular Contributor
timestamp: August 04, 2014, 10:17:55 pm
content: Quote from: SeanB on August 02, 2014, 06:00:18 pmOk, great, thanks for the information.When I tested the PSU all lines were good, but when the PSU is plugged in, all lines get lost except for the 5v.Does this mean that the faulty capacitor is after the PSU ribbon cable? On the relative board connecting?I will say if I remember correctly the caps on the PSU in question looked like the bottom seal might have leaked.Although when testing the PSU without a load, everything was great.Its been a while also, but the ESR reading seemed to check out iirc...The PSU ribbon goes to the motherboard, the board has tons of SMD caps.
Repair and parts for Philips HTS 5100b Home Theater System - Page 1
Forum section: electronics / beginners

author: Coll
author_rank: Contributor
timestamp: June 06, 2018, 01:50:13 pm
content: Hello I am currently working on repairing Philips HTS 5100b Home Theater System. I managed to find a service manual for it and have been trying to figure out the issue. Problem 1 is my brother ripped the optical audio receive port right off the board and burned some traces off that side. The other issue is randomly goes into protect mode and shuts itself down. After opening it up and checking some measurements I notice the wattage while the device is on is around 28W but drops to 23 when it starts to go into protect mode. I also notice that the supply to the amps dies off and goes from 46V to 0V. With that it brings the thermal warning pin low cause the main controller to go into protect mode. I first thought maybe the amps were getting to hot so I replaced the thermal compound. Didn't fix the issue, but I did notice another device was heating up far hotter than I believe is reasonable when the device goes into protect mode. What is weird is I don't exactly see a connection to this part of the circuit that might affect the amps, but I don't think this is a coincidence. I pulled off that device it being a FCQ20A06. Tested both forward voltage drops and only getting about 0.150V which is far below the 0.5V that the datasheet specifies. I believe I measured a short while this device was still in but have since been unable to find it. The low voltage drop shows it is failing but it still blocks reverse bias. I believe this device is failing intermittently and when it does completely shorts inside dragging down the supply for the amps. How this happens is unclear to me. There could be a short on another part of the board so I will keep test around.What I am asking for is help finding replacement parts as most of them seem obsolete.I need a torx177l optical receiver jack or one equivalent in dimensions and voltage specifications.https://www.mouser.com/datasheet/2/408/totx177l(f,t)-1209461.pdfI also need a replacement FCQ20A06 or equivalenthttp://html.alldatasheet.com/html-pdf/91351/ETC/FCQ20A06/47/1/FCQ20A06.htmlMight be a long shot, but it would be nice to get this device working again. Holds find and everything seems to operate fine besides the random shutoffs. So I don't think anything too critical was damaged. Hopefully more experienced engineers can shed some insight. I am having fun troubleshooting this with the skills I have learned so far, but I am no where near the level I wish to be, and I wish my schooling allowed me to do stuff of this nature.
Repair Horizon CT 7.1 Treadmill - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: January 14, 2020, 08:41:35 pm
content: Hi I have Horizon CT 7.1 Treadmill that was working good, but for some reason i stop using and it was stilling in my basement for about a year, after start using again, initially it worked good but soon it got problem while starting up.Initially when i turn it on while displaying self test it beeps twice and self test display gets stuck (refer to images) after about 10/20 minutes it beeps again gets normal and i was able to use it. after keep using for about a month, it totally stopped working, now when i turn it on self display appears, beeps twice and then nothing happens.I googled the issue, found one post describing exactly same but did not get the solution, i was looking for some help where to start, what could be the reason?

author: thm_w
author_rank: Super Contributor
timestamp: January 21, 2020, 11:27:18 pm
content: Open it, take photos of the control boards, look for any: burned components, damage, leaking caps, etc.What is the power source for it, 120V in?Some information here but may or may not be relevanthttp://productload.johnsonfit.com/inc/uploaded_media/ba2e870dabd6373a48f8e138dfc9c56f/service_guide/54c14b21a33d970fb0beb252b7d83034.pdf
Repair of HiFi Amp - Transistor as a voltage regulator - Page 1
Forum section: electronics / beginners

author: riffmaker
author_rank: Newbie
timestamp: February 22, 2019, 12:19:26 pm
content: Hi All,I am currently repairing an audio amplifier (Harman Kardon TA600), I discovered that one transistor was dead on the power supply board (I attach the diagram from harman, I highlighted in red the transistor that is not working anymore). The only information written in the user manual for this component is : 43029387 NPN power silicon. I tested each of the pin with a voltmeter before removing it, and it was 0V a the emitterI desoldered the component and I unfortunately broke a pin, but I attach you a pictureDoes anyone knows how I could replace it ? Which modern reference of transistor could fit ?Thank youPierre

author: dzseki
author_rank: Frequent Contributor
timestamp: February 22, 2019, 12:27:24 pm
content: Depending on the available space BD139 or BD239 would do. But the pinout of the transistor should be verified!

author: jackthomson41
author_rank: Regular Contributor
timestamp: February 22, 2019, 01:49:26 pm
content: Quote from: riffmaker on February 22, 2019, 12:19:26 pmyeahBD139, BD140 or BD137, they all can work and which one you select compare its pinout with yours.

author: riffmaker
author_rank: Newbie
timestamp: February 22, 2019, 02:18:48 pm
content: Thank you for your answers !Unfortunately, I checked with the original pinout, that doesn't fit... (I need the base pin at the center)I found this reference : ZTX692B (datasheet attached)Do you think that it could work ?

author: Benta
author_rank: Super Contributor
timestamp: February 22, 2019, 02:49:52 pm
content: That looks a lot like a Motorola MPSU06 (NPN) or MPSU56 (PNP). Common in amps from the 80s. If you're lucky, you might find NOS parts somewhere.

author: riffmaker
author_rank: Newbie
timestamp: February 25, 2019, 09:20:15 am
content: Thank you Benta, you're right that seems to be that reference !I now have to find some on the internet...

author: 6PTsocket
author_rank: Regular Contributor
timestamp: February 26, 2019, 12:10:57 am
content: Did anybody notice that the 30 volt output is labeled 29.2 volts on the same wire if you follow it onto the circuit board?Sent from my SM-G900V using Tapatalk

author: bson
author_rank: Unknown
timestamp: February 26, 2019, 12:38:19 am
content: Also check C5. If C5 is unable to hold a charge and effectively shorts, Q2 could be fried due to an excessive B-E voltage.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 26, 2019, 06:38:26 am
content: My old Interstate (Racal Dana) F43 function generator uses those same Motorola transistors as final output. After an... er... untoward eventI was able to find NOS replacements at UTSource. They have always been good to me.
Repair of racaldana 9906 universal timer counter  - Page 1
Forum section: electronics / beginners

author: calsytech
author_rank: Newbie
timestamp: December 31, 2024, 03:38:36 am
content: My timer runs when i press but time is not matching let me know any components to be replace

author: Analog Kid
author_rank: Super Contributor
timestamp: January 01, 2025, 01:07:51 am
content: Um ... you're going to have to give a bit more information if you want someone to actually help you here.

author: MathWizard
author_rank: Super Contributor
timestamp: January 01, 2025, 08:46:58 am
content: Do all the lights/modes/switches still work? IDK for sure how counters work but do any of the ranges still work ?Seems the schematic is hard to find, but this might help, using the 9905https://www.eevblog.com/forum/testgear/need-a-schematic-for-racal-dana-9906/
[Solved] Repair: replacing heatsinked high power TO-220 with D2PAK? - Page 1
Forum section: electronics / beginners

author: llkiwi2006
author_rank: Regular Contributor
timestamp: February 27, 2018, 09:04:24 am
content: Hi,I am working on repairing an audio amplifier that uses twoLM4752in through-hole TO-220 package vertically mounted to a big aluminium heatsink. The chips have blown and I could only find replacements in surface mount D2PAK package, so I wanted to ask what is a good way to mount the D2PAKs to the heatsink? The amplifier is rated that each of the chips could output 15W of power, so good heatsinking is essential. I was thinking along the lines of somehow gluing them to the heatsink while maintaining good thermal contact, and then just soldering wires to connect each individual pin to the pcb.Thanks in advance.

author: gasmeter
author_rank: Contributor
timestamp: February 27, 2018, 09:20:57 am
content: HiWhatever you do you need good thermal contact.It's a To-263 package as you say similar to DpakOptions are ...Thermally conductive aryldite if you want to glue it.A good option would be a thermal pad or grease and make a small aluminium block / clamp to adapt it to your heatsink mechanics.You could also cut a copper rectangle, solder the device to it then voila you have a pretend To-220 package. (Preferred option I think)Just bear in mind every mechanical interface point has thermal resistance.I hope that helps.Peter

author: llkiwi2006
author_rank: Regular Contributor
timestamp: February 27, 2018, 10:47:20 am
content: Thanks gasmeter.I found some 15mmx15mm copper plates on ebay for cheap, so I'm going to order some and see how well soldering the D2PAK chips to them works.

author: langwadt
author_rank: Super Contributor
timestamp: February 27, 2018, 11:45:24 am
content: D2PAK is basically a TO220 with the mounting hole cut off. Clamp it to the heat sink with something similar to thishttps://media.rs-online.com/t_large/RD504059-01.jpg

author: llkiwi2006
author_rank: Regular Contributor
timestamp: March 17, 2018, 12:41:47 am
content: For anyone curious, here are some pictures of what I ended up doing. Soldering leads to the legs proved to be the most painful (literally burning my fingers). I used some thinner (awg30) wires for the second one, and that turned out to be a lot easier to solder and insert into the board. Overall I'd say it worked pretty well.

author: Rog520
author_rank: Regular Contributor
timestamp: March 17, 2018, 12:50:10 am
content: Sorry to be a late reply on this one, but the LM4752T (TO-220) shows availability here (Canadian source):https://www.componentonline.com/search?search_key=LM4752TAnd a couple of ebay sellers list them, too.

author: llkiwi2006
author_rank: Regular Contributor
timestamp: March 17, 2018, 05:56:45 am
content: Quote from: Rog520 on March 17, 2018, 12:50:10 amThansk for your help anyway. For me I would've just been a lot more costly to try get the obsolete (TO-220 version) part and get it shipped to NZ. In the end I think my DIY solution worked quite well (see a previous reply for pictures).
Repair Samsung Smart TV - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: March 17, 2019, 06:58:23 pm
content: Hello guys,I do need the help of the masters from this forum.I have this samsung smart TV model UE40JU6550UXZG and another internal SN CY-WJ040HGLV3H.It has NO backlight and NO image. I have repaired an old Toshiba LCD TV without backlightbut there was image. The problem was from a LED bar strip.With this one I was thinking it is the same issue and I have completely disassembled the TVand I have checked all the LED bars and all are OK.After this, I have assembled back the LCD and the related components.When the blue board is connected to the yellow board, the TV starts but without backlight.If I remove that flex from the red curve, the backlight starts when I power on the TV.The yellow board I understood it is the T-CON board.It is possible to be only that the problem? Is there any way to check it to be sure?On the tcon board there Ive made a purple rectangle and there is a coil that goes into a small ic and the otherside of the coil it seems it is connected to GND or it is a short circuit on that side?With all the flatcables connected between the boards and with that coil removed, the TV starts withbacklight but without image.I really appreciate any help and ideas to solve this problem.Kind Regards!

author: Ghitza
author_rank: Contributor
timestamp: March 18, 2019, 11:57:56 am
content: No idea related to this problem guys?I don't know for sure if I can order that tcon board or not.Maybe someone has already encountered this problem.Thanks in advance!
Repair TV Led backlight, how to know which led is 6v or 3v - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: July 04, 2024, 09:21:01 pm
content: Hi,My Tv backlight was flashing and after replacing three individual led's on three backlight led strips a few times, the replacement led's keep burning up. The original led's on the strips are fine. I think it has something to do with 6v or 3v led's. Can someone tell how to see the difference between 3v and 6v led's. Many thanks in advance

author: thm_w
author_rank: Super Contributor
timestamp: July 04, 2024, 09:59:54 pm
content: What is the model of the TV, has anyone else stated what part number is used?You can apply 3V with a current limited supply and see if it lights up, if it doesn't go a bit higher.There are lots of tutorial videos on youtube

author: Bud
author_rank: Super Contributor
timestamp: July 04, 2024, 10:47:34 pm
content: Use a multimeter in Diode mode across the LED, it will show you the voltage drop in forward connection.

author: robsims
author_rank: Frequent Contributor
timestamp: July 05, 2024, 12:40:27 pm
content: ok thanks guys. I have another question, when i turn the powersupply of the tv off, some backlight led's still light up. So the powersupply led driver doesn't fully turn off. Anyone know what the problem with the powersupply led driver might be?

author: thm_w
author_rank: Super Contributor
timestamp: July 05, 2024, 09:18:58 pm
content: Quote from: robsims on July 05, 2024, 12:40:27 pmTurn the power off with a soft power button? Or physically switch something off?LED stays fully lit, or very dim?If its super dim it could just be a bit of leakage through some capacitors. If its reasonably bright, sounds like some component in the LED PSU or main PSU is damaged to the point it doesn't shut off completely.

author: robsims
author_rank: Frequent Contributor
timestamp: July 05, 2024, 11:11:47 pm
content: Turned it off and the led's are superdim. So i have to check the capacitors. I also noticed that when i turn the tv on, the backlight led's start burning very bright, then shut off for a very brief moment and then light up again. What may be wrong here?
Repairing a 12 dc power supply. - Page 1
Forum section: electronics / beginners

author: bustedparts
author_rank: Newbie
timestamp: August 29, 2017, 06:56:50 pm
content: I do alot of RC car racing. This is just a part of my hobbies. Anyway one evening I hear someone started cursing and I watched this person toss this power supply in the garbage. Well being the curious person am I took it home to see what was wrong with it. Hoping it is something simple like a blown mains fuse. I opened it up and found the fuse blown and I replaced it. When I power it back up and turn it on it quickly blows the fuse. No I have been sitting on this unit for about a year because I knew I was going to study more on the electronics and this would make a great repair project. So I contacted the manufacture and I asked if i could get a diagram of the unit. I could not get one due to they dont manufacture them . So getting a schematic is out of the question. So now I need to reverse engineer it in order to properly test the circuits to find out what isn't working . So I am looking for pointers on how to draw out a schematic in reverse order. Or maybe a guide on a proper work flow. It is something I have never tackled and any advise would be awesome.

author: jeroen79
author_rank: Frequent Contributor
timestamp: August 29, 2017, 09:13:54 pm
content: Brand and type?Can you post some good pictures of PCB?

author: CJay
author_rank: Super Contributor
timestamp: August 30, 2017, 10:31:36 am
content: Have paper, pencils, a multimeter, a bright light and the 'net to hand.Draw small sections of the circuit first, find the controller chips and datasheets, they'll probably have an application circuit in there which can make your life a lot simpler, most manufacturers don't stray too far from the application notes for commodity items.The bright light can help if it's a fibreglass board as some are translucent and you can trce tracks on a double sided board by holding it up to the light.The multimeter because you can use the continuity function to trace connections and 'buzz out' transformers, chokes etc.
repairing a cap by refilling it... - Page 1
Forum section: electronics / beginners

author: MyHeadHz
author_rank: Regular Contributor
timestamp: March 02, 2019, 12:05:39 am
content: Is it possible to revive a cap by refilling it with electrolyte, like using a syringe? I know there is a process to repack big caps, but I mean for small ones.

author: FotatoPotato
author_rank: Regular Contributor
timestamp: March 02, 2019, 12:07:01 am
content: No, not that I know of. Just get a new cap

author: Gyro
author_rank: Super Contributor
timestamp: March 02, 2019, 10:36:15 am
content: Theoretically, I suppose. Your problem though is that you have no idea what composition of electrolyte was originally used (they vary significantly between manufacturers and types) and you have no way of purchasing it.That makes it a practical (and economical) non-starter.

author: wraper
author_rank: Unknown
timestamp: March 02, 2019, 10:41:11 am
content: Quote from: Gyro on March 02, 2019, 10:36:15 amThe other problem that capacitor failing is not simply electrolyte evaporating. There are more complicated processes behind it. Also how you are you going to safely seal it again and keep vent still doing it's function?QuoteThere is none of such BS.

author: Shock
author_rank: Super Contributor
timestamp: March 02, 2019, 10:55:20 am
content: Quote from: Gyro on March 02, 2019, 10:36:15 amAs that leaf falls 100 new Chinese businesses start up selling refurbished name brand capacitors.Even if you got the electrolyte right, there is other related problems like damage to the dielectric that would make it waste of time as well. I think reforming is about as far as I'm willing to go.But transplanting electrolyte sounds like a fun evening of experimentation. Who knows it could take off like ink refills.

author: Gyro
author_rank: Super Contributor
timestamp: March 02, 2019, 10:58:06 am
content: Quote from: wraper on March 02, 2019, 10:41:11 amThere is a process where people remove the guts of old capacitors and fit smaller modern ones inside for cosmetic reasons - retaining the 'look' of old valve amps for example. Certain dodgy Chinese sellers carry out a similar practice with low rated, low quality capacitors inside premium quality brand cans for reasons of profit, but that's as far as 'repacking' goes.

author: wraper
author_rank: Unknown
timestamp: March 02, 2019, 11:06:42 am
content: Quote from: Gyro on March 02, 2019, 10:58:06 amThat's not repacking. It's placing different capacitor inside of cosmetic shell.