Worst part is I could have avoided buying a new TV, as the initial repair (3x capacitors) was correct.
However, the new TV uses around 400W less than this TV, so this one's off to ebay
psmedley
Senior Member
Last Activity: 05-10-2015, 07:44 PM
Joined: 04-14-2012
Location: Greenwith, SA
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Re: Samsung PS50Q91 Plasma won't turn on
Worst part is I could have avoided buying a new TV, as the initial repair (3x capacitors) was correct.
However, the new TV uses around 400W less than this TV, so this one's off to ebay
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Re: Samsung PS50Q91 Plasma won't turn on
OK I'm officially an idiot.
I found the VS_ON pin this afternoon on an empty connector. I then noticed a ribbon cable behind the PSU.
Seems I forgot to make one connection after replacing the original 3x failed capacitors. After making that connection, the TV turns on and gives me a picture
Thanks all for the suggestions
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Re: Samsung PS50Q91 Plasma won't turn on
Will take a look for vs_on when I get home.
PS_on was around 3.3v whilst in standby mode and dropped to 0.6v whilst it was trying to start up. Does this still suggest a main board issue?Leave a comment:
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Re: Samsung PS50Q91 Plasma won't turn on
Just been reading some more old threads - PS_ON is only around 0.6V whilst the TV is trying to power up, is this what should be triggering Vs to come up in voltage?Leave a comment:
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Re: Samsung PS50Q91 Plasma won't turn on
Photos of boards/TV are attached. Sorry for the quality, lighting wasn't great, and after recent knee surgery I couldn't move the set by myself.
I just did some voltage checks whilst the TV is powering up. Most voltages from the PSU appear in line with the markings, however, Vs is measuring 0V instead of the 200 or volts it should be! Va is 65V in line with the label on the panel.
This would suggest the problem is with the PSU as Vs is not coming up?...Leave a comment:
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Re: Samsung PS50Q91 Plasma won't turn on
Confirmed. With all boards unplugged from the PSU, except for the main board, the TV powers up, startup sound plays, then it powers down and 'reboots' and the cycle continues...Leave a comment:
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Re: Samsung PS50Q91 Plasma won't turn on
Would I be correct in thinking that if I disconnect the boards other than the main/input board and the PSU, and try and turn the TV on, that if the TV then completes power up, then the problem lies with one of the other boards?
If it still fails to power up with just main/psu connected, then the problem is with the main or PSU boards?Leave a comment:
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Re: Samsung PS50Q91 Plasma won't turn on
Uggh I got the model number wrong in the above.
The actual model is PS50P91.
Major difference is the Q91 was HD, but not full HD. The P91 is full HD. I used to have a Q91 that I was trying to fix. The buffer boards look quite different on this TV, although it may be partly due to the heatshields over them.
I was planning to take some photos this afternoon but started drinking instead
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Samsung PS50Q91 Plasma won't turn on
Hi Guys,
Arrived home from a week's vacation and found our approx 7 year old Samsung Plasma tv - model PS50Q91 wouldn't turn on.
The red standby light was flashing and there was a weird almost popping sound with each flash.
Removed the back from the TV and found 3x 10V 2200uF capacitors that were obviously failed. Replaced these and now the standby light remains solid red and the weird noise had gone.
However, on turning the TV on, the startup chime played, however, the screen didn't light up and the TV powered off with a flashing standby... -
Re: Soniq L32V12A 32" LCD won't turn on
Hi Len,
I actually got distracted on some other projects and haven't got back to the tv yet. Based on your symptoms I'd be suspecting bad caps on the power supply...Leave a comment:
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Re: Soniq L32V12A 32" LCD won't turn on
Checked out the caps on the main board - there are several with marginally high ESR, and several with very high ESR. I'll recap it over the next few days and see how I go.
Thanks for the help thus far...
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Re: Soniq L32V12A 32" LCD won't turn on
Will check that input tomorrow, however note that the standby light does not change colour when the power button is pressed, so I'm not expecting audio.....Leave a comment:
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Soniq L32V12A 32" LCD won't turn on
Hi All,
Got this 32" HD LCD tv from ebay a few months ago real cheap, and finally got around to taking a look.
Photos attached showing layout.
Power supply is a Megmeet MIP320FL. No caps appear bulged, but a couple of them test a little high for ESR (tested in-circuit). Caps are a mix of Samxon, CapXon and Aishi.
Video board is labelled ST306TP-T7 - caps are KLA anda gain, none appear bulged.
Symptoms are when the power is turned on at the mains, the red standby light on the front of the TV flashes 4 or 5 times, but no response...Last edited by psmedley; 07-01-2013, 03:31 AM. -
Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
Vsc is 2 - 3 volts - not 190... what are the most likely causes?Leave a comment:
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Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
one of the buffer chips... looking at the other buffer chips, they all have slight upwards lumps/bumps on the surface of the chip, so I guess they're all on their way out...Leave a comment:
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Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
reconnected ribbon cable, with lower buffer only connected. Turned on power, got humming from ysus but no picture, waited a short while after sound came on, and got a slight puff of smoke from the lower buffer board, so ripped the power cord out.
Looks like the lower buffer board is toast too now
No smoke from the ysus though, so hopefully that's still ok.
Is there anything I should check on the ysus to confirm it's OK?
I think I see some test points for...Leave a comment:
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Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
idiot alert... lying in bed last night, realised I forgot to connect the ribbon cable from the main board to the ysus - no no surprise there is no picture. will reconnect when I get home from work and try againLeave a comment:
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Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
OK ysus is back together.
Sound with no picture with no buffer board installed (no surprise).
Installed the lower buffer board only - still no picture which was a bit of a surprise although tw2005 mentioned the same thing with his similar model Samsung.
Not brave enough right now to reinstall the upper buffer... I have removed the melted upper buffer chip, and the shorts to the three bottom pins are now gone...
checking the pins tom66 suggested earlier - the...Leave a comment:
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Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase
Ysus repair kit arrived today (6 days from UK - impressive). 3 pin mosfets installed ready to solder, still need to install the surface mount mosfet and work out how best to solder the base to the PCB.
Also need to test the resistors that are included in the repair kit R5508, R5509 and zener diode ZD5502 - although the zener appears visually to be ok.
The included 680uf 25v caps were Jackcon - they'll be going straight in the bin Already replaced them with Rubycons Will try finish...
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Hi there,
I think it's hilarious that we're both working on virtually the same sets and we're both in deeper than we'd like but can't let go because we love fixing things.
Anyway I'm at work so i can't see my Y-sus board but mine is a LJ92-01490A and i assume yours is the same.
Do you have a list of electrolytic caps on that y-sus, I want to get an order into RS b4 530
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