TV Repair - Page 1
Forum section: electronics / repair

author: ZaXaZ
author_rank: Contributor
timestamp: October 17, 2018, 03:45:01 pm
content: HelloSo my tv has started doing the famous blinking with the standby led. (i did not know they had a blink code witch I did not note it down)I hoped it would just be a simple case of a capacitor that went BOOM! but none of them have blown the top so now I have no clue what to do.The TV is a Philips 47pfl6877T/12 I live in Denmark but for some reason, 90% of all I find on google with this tv model is in polish/Russian witch won't help much.I did manage to find a service manual, but I can't find the places on the physical print to measure on.I have taken it out to do a closer visual inspection and can't find any damaged parts on the PCB. all I got to work with is a somewhat cheap multimeter and a soldering ironIs there anyone who would be so kind as to assist me in trying to fix this tv?I know it will take some time, and is far from a 5 min thing but I'm willing to put in the time if it means there is a chance I can repair it compared to buy a new tvmy current knowledge of this is very basicFiles:philips_chassis_qfu2.1e_la.pdf Is the repair manualPictureshttps://drive.google.com/drive/folders/1VmpakqvjnreEHhgTroc2fJBEnO4JIu1-?usp=sharing

author: PKTKS
author_rank: Super Contributor
timestamp: October 17, 2018, 04:18:24 pm
content: Unlikely to be just a cap.This CHASSI uses a proper troubleshooting procedureThe manual is very handy - and as you already found it you shouldfollow the "SETUP" in Diagnostic (Service) mode primary modeOnce you start the manual will guide you in converting the error codesto figure out what it is wrong or at least some clue to startA considerable practice is needed to open and deal with such CHASSIsthe proper service mode page is shot here as attach...find that page to start the "SERVICE MODE"...Paul

author: ZaXaZ
author_rank: Contributor
timestamp: October 17, 2018, 04:33:29 pm
content: it won't turn on at all, and I cant get it to flash again so that makes if very hard to get to use this "SERVICE MODE"also i fail to find nay translating of blinks in the manual?

author: PKTKS
author_rank: Super Contributor
timestamp: October 17, 2018, 04:42:34 pm
content: Yes don't expect that it will magically 'turn on'The Service Modes each has it's own reason to troubleshootsome particular sectionThe ERROR CODE table is in the next page... of my shotTo enter all the modes they also suggest their tool (should besome sort of firmware probe)...I doubt anyone outside the authorized should have this..so we need to carve the tips on the manualIt looks that your version of the manual may be missingor be just a summary ...Two more shots to see the propr pages

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 17, 2018, 04:45:48 pm
content: Quote from: ZaXaZ on October 17, 2018, 03:45:01 pmIt may still be a defective capacitor. They don't always go as far as have their vent blown up. They may just inflate a bit (bulging vents) and that'd be barely visible. They may even dry up without any significant external sign.As a first step, I would still unsolder all the electrolytic caps (there are not that many), control them and change them anyway.Also look for dry solder joints. From the pictures it's hard to see well.

author: PKTKS
author_rank: Super Contributor
timestamp: October 17, 2018, 04:54:08 pm
content: May be.. but the chassi is BIG.. and all digitalThat means a lot of guessingA clue were to start will help

author: ZaXaZ
author_rank: Contributor
timestamp: October 17, 2018, 05:15:57 pm
content: I have no clue how to read that "diagram" layer one has a lot of numbers in common and it seems unlikely that it would blink over 30 times with some of the numbers in layer 2 is.I can't remember how many times it did blink but it was 3-5 ish +/- 1 or 2But there is under 10 caps I could remove them and test them, tho I'm not sure how to do that with only a multimeter most of the videos that say "test caps with just a multimeter" then use another toolThis is my MM i wish i had a better one just ain't got the cash for it atm and all i normally use it for is to test is there is a connection and/or somewhat close to 12 volt (working on cars)

author: Cherenkov11
author_rank: Contributor
timestamp: October 17, 2018, 05:39:51 pm
content: First of all, I have a little experience fixing tv's, but when we face a problematic TV our first thought is always the PSU because is the mos likely to fail, but not always, with new TV's, especially smart ones, the main board may be the real problem.Recently I fixed a LG smart TV, no image, no backlight, no audio, no nothing, only the standby LED. I though that the PSU was the faulty one, but not, I checked all the volatges and all were correct, the real problem was on the main board, I had to reflow the main chip, heating it and the TV turn on again.I'm not saying that you have the same issue as mine, I'm just saying that the PSU it is not always the problem, if you have image but not backligh, must likely the caps on the inverter are faulty. But if you have similar symptoms as the TV I mentioned, the main board could be the real problem.Note: I don't recommend you test the capacitors, just replace them, if the tv has a couple of years working it is pretty normal that caps fails, even if they look good physically.

author: ZaXaZ
author_rank: Contributor
timestamp: October 17, 2018, 05:55:48 pm
content: Tv is 4-6 eyars old i would bet.most reviews of this tv is from 2012 so around there.the im not sure if its hard to see if there is an image but no backlight i have never see that. but i thing i got NO: image no light and a standby led that blinks a hand full of times and pause for a while and keeps blinking i just assumed the pause was a recharge time

author: Cherenkov11
author_rank: Contributor
timestamp: October 17, 2018, 06:05:46 pm
content: I thinks, firstly you need to check if the power supply is working correctly, in some service manual there is a complete procedure on how to check all the voltages, so you need to do this first, and when you are 100% that the PSU is working correctly it is time to check the main board, that to me, it most likely the cause of the problem

author: ZaXaZ
author_rank: Contributor
timestamp: October 17, 2018, 06:17:31 pm
content: That was mostly my plan also.i am how ever not sure where to check all the voltages at. the first one it wask for is C306 and i cant find that sucker any where. i can find C300-C303I marked them with color to the point i assuem they corolate with. but i cant find any more than that?

author: Cherenkov11
author_rank: Contributor
timestamp: October 18, 2018, 02:35:32 pm
content: Well, sorry for taking a long time to answer, I go to the college and don't have a lot of spare time. But, what I got is that I found the schematic of the PSU, I'm gonna attach it, there it is the voltages of the power supply. But, for my expierece if all the connectors are detached you only have to get the standby voltage ~3.3V, PIN 1 CN4, so, to turn on the power supply you may jump the STANDBY PIN 2 to ground (PIN 3, 4, 9, 10)and now you are going to get the 12V on all the pins marked with 12V3.Check that out and confirm the voltages. The other part of the power supply is for the backlight driver, but to turn this on the lights must be connected to the board, the BL_ON pin 11, may turn the backligh ON, but for the diagram I think it must put it up, but I don't know with what voltage, maybe 12V.

author: ZaXaZ
author_rank: Contributor
timestamp: October 19, 2018, 05:10:00 pm
content: i got it blinkin again.it keeps repeating 2 blinks rather close togeather then a 3-5 sec pause then repeat.

author: ZaXaZ
author_rank: Contributor
timestamp: October 19, 2018, 05:34:40 pm
content: mesuring on CN4(no short from ground to pin 2 or anything but power connected to powersupply)pin 1 to ground = 00.0mV(short from ground to pin 2 or anything but power connected to powersupply)pin 1 to ground = 00.0mV i did do a quick small jump witch i did not get to note.with no power i tested for ground spots on the CN4 and i dont have ground on pin 14 but 1 do get ground on 11 and 12 is that the way it should be?when i plug in power GT 1 and 2 make a spark is that normal?

author: ZaXaZ
author_rank: Contributor
timestamp: October 19, 2018, 06:34:29 pm
content: Quote from: SiliconWizard on October 17, 2018, 04:45:48 pmI know i should have real tester for a cap, but i don't have one so i just tried to see how many V they individual had when the tv was in standby witch si way less than the number on the sideC907 is having 12,3V on standby and 17,71-17,78V when the tv is dopoing the blink code thing. it's marked on the side to 50V is that a valid way to test is ifs dead?

author: m3vuv
author_rank: Super Contributor
timestamp: October 20, 2018, 11:10:43 pm
content: this screams high esr to me!!,if you dont have an esr meter buy or make one,its always my first port of call with switch mode power supplys,im suprised no one mentioned it!!

author: ZaXaZ
author_rank: Contributor
timestamp: October 20, 2018, 11:14:59 pm
content: Quote from: m3vuv on October 20, 2018, 11:10:43 pmwhat do u mean with this high esr?

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 20, 2018, 11:41:48 pm
content: Quote from: ZaXaZ on October 19, 2018, 06:34:29 pmI'm afraid not.But as I suggested, you'll lose a lot less time replacing all electrolytic caps, won't be very expensive. And if the problem lies elsewhere, well you have them changed preventively.

author: nano111
author_rank: Newbie
timestamp: October 29, 2018, 06:42:23 pm
content: hi,I do not know if you have same psu board but look this in attach.It helped me .

author: ZaXaZ
author_rank: Contributor
timestamp: October 29, 2018, 07:28:43 pm
content: Quote from: nano111 on October 29, 2018, 06:42:23 pmi will have a look at it thx!