Beginner needs help with repairing TV power supply - Page 1
Forum section: electronics / beginners

author: Nosnibor
author_rank: Newbie
timestamp: January 03, 2016, 11:11:30 pm
content: Hello, first I appreciate your patience and I hope someone is able to mentor me through this process. First I will start with some details. I am attempting to repair a Samsung Plasma TV model PN60E7000. The TV will shut of and do what I guess is called "cycling" the power but basically I get some clicking. The TV will not power back up without being unplugged. So I have some knowledge as I have built computers but when it comes to all the pieces on a board I start to fall off. I took the power supply out today and hoping I would find a blown capacitors because I know that is probably the easiest thing I could do however I could not identify any like that. So I started looking for more answers online and it started getting into very technical things over my head. I can't tell if the fuses are blown because I think they are ceramic and from some videos on youtube I guess I have to start testing individual components on the board to see if they are shorting? Also I read that a bad solder joint could also be the cause but I don't I recognize any of those either.If anyone has any suggestions on where I should start I would appreciate it. The power supply S/N is CN07BN4400514ASK28C871668. Thank you for your time.

author: DimitriP
author_rank: Super Contributor
timestamp: January 03, 2016, 11:19:20 pm
content: Welcome and Happy New Year!!!Have a look here and here and here :http://www.ebay.com/itm/BN44-00514A-PN60E7000-Samsung-Power-Board-Repair-Kit-For-VS-200-and-VA-60V-/201455734352?hash=item2ee7b28e50:g:efwAAOSwwbdWLbtOhttp://www.ebay.com/itm/Repair-Service-BN44-00514A-Power-Supply-Boards-for-SAMSUNG-PN60E7000-PN60E8000-/181947805780?hash=item2a5cef3054:g:Hd8AAOSweW5VchIuhttp://www.ebay.com/itm/REPAIR-SERVICE-PN60E7000FFXZ-POWER-BN44-00514A-TURN-ON-NO-PIC-OR-DEAD-POWER-/272074979484?hash=item3f58eeb89c:g:s9MAAOSwxN5WbG3e

author: Nosnibor
author_rank: Newbie
timestamp: January 03, 2016, 11:23:10 pm
content: Quote from: DimitriP on January 03, 2016, 11:19:20 pmThank you for the reply. I have seen packages like these before. I guess I was concerned that I would get them but because they are just based on "what is most likely to fail" I wouldn't actually get the problem fixed. However I guess it will give me the experience I could use to replace components.

author: natbuk
author_rank: Contributor
timestamp: January 03, 2016, 11:26:29 pm
content: In terms of 'blown capacitors', for electrolytics, look for bulge in the top - they usually have a 3-way built in weakness (in case the pressure builds up, at least they explode more gracefully!). Any bulging caps, replace them with long life, high-temperature, low impedance types.You can buy a capacitance ESR meter which measures the AC impedance. They're fairly dear, though - around 50 UKP. They measure the effective resistance at some frequency (usually 10kHz, or sometimes 100kHz). As aluminium electorlytic capacitors age (and are baked up byt the heat!), they go impedance. This can affect all sorts of things and make marginal problems that can be hard to track down.Usually, the easiest thing is to just replace them, and be done with it (if you don't have a meter, and if your time is in any way valuable).If there are any tantalums in there (fairly unusual now) look for blakening.You can also often see where the PCB has got hot by discolouration (or even better, if you can run the unit looking at the PCB with a thermal camera). Hot areas are good places to start looking for intermittent faults.

author: Nosnibor
author_rank: Newbie
timestamp: January 03, 2016, 11:29:31 pm
content: Quote from: natbuk on January 03, 2016, 11:26:29 pmI think the only thing I understood was blown capacitors. I was looking for the bulging but I didn't see any of that. Is it possible that without the bulging they may still be bad?

author: DimitriP
author_rank: Super Contributor
timestamp: January 04, 2016, 01:21:24 am
content: Yes capacitors can fail without any bulging.I've repaired one of my monitors with no visual clues as to which capacitor was bad.In doing a search just to find if it's a common problem and sure enough I stumbled on someone selling a replacement capacitor kit for my model.I stopped right there.It was worth ordering the kit, just in time saved having to dissasemble the monitor, make a list of all the capacitors, find them on Digikey or mouser or whererever, and then wait for them.BTW the guy selling the kit was one zip code away so they got to me fast.Sometimes you get luckyThere is at least one miserable video on you tube of a guy with $7000 worth of instruments , checking out a power Supply and in the enD the capacitor that was failing was the one he decided he didn't need to check. (Yeah... names withheld to protect the Guilty) Ridicilous!edit: creative spelling corrections