Samsung PS51E450A1WXXU (Live coax potential cause)

[necstandards]

Hi - having a problem where i have sound but no picture at all. Not sure if its related to an issue i discovered where i have a sat receiver in my attic, during the recent cold spell, condensate manged to drip on this receiver, shorting somehow but making the coax output live - therefore 230 AC was presented to the receiver board of the TV (seems too much of a coincidence but lets see)

Remove the back panel - green LED on the logic boards is on for ~ 5 sec, off for 2 etc.
Examined all boards (with limited knowledge) but didn't see anything out of the ordinary!

So have checked some of the voltages;
VS = 199.8 (sticker = 201)
Va = 58.4 (sticker = 58)
VSC = 1 (sticker = -180)
Ve = 37 (Sticker = no reference)

Checked the fuse on the XYmain and seems fine.

So now i haven't a clue so hoping for some advise
Thanks - Jody

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Just adding some pictures

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Update
Have read through alot of treads and its seems “If Vsc is low or missing and Vs was OK, the failure is with the Y/X-Board since the Y- Board section generates the Vsc voltage from the Vs supplied by the SMPS.”

Was going to just try change the Y-main board and found one, LJ41-10181A, FB 880A A7 28P 3GL – AA7, but I have a FB 880A A6 27P 1HN – AA6, however the printed LJ41 #'s are the same, but the sticker is different, so will that be a problem – sorry I don't know what these stickers mean.

Thanks again.

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Update,
Have decided to try my luck with a replacement Y-Main card. Fingers crossed i have it before xmass, i dont blow myself up and can enjoy my 51" screen again

Great forum i have to say, there is vast amount of information within. Two weeks ago i knew nothing about plasma TV's, now im hoping to fix my own - Thank you all.

[dick_barton]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Have you checked the Ybuffer board for shorts. Look on Youtube for how to test the buffers. Plenty of good information available.

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Just checking the buffer board but not fully sure which pin on the y main connectors I have to use, one video said it didn't matter some more say to look for a pin that's connected to all (that I can't see)??

[dick_barton]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Using you meter to test the Ybuffers, connect your meter leads with meter set to ohms between SVC_OUTL and SVC_OUTH and check for a low resistance or short circuit.

Next check with one lead on SVC_OUTL and with the other meter lead, slide it slowly and carefully down each of the pins of the CN5500 connector, first front pins and then back pins again looking for a low resistance or short circuit.

Take your time and repeat for all the connectors like CN5500

Finally repeat the same test but with the meter lead on SVC_OUTH

Any low or short circuit reading is a bad buffer output.

[tom66]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

If 230V got exposed to the main board, I doubt most of the low-voltage side of the set is still working. Are you sure you weren't testing incorrectly? Note this set has an earthed chassis so any short to the chassis should trip a household GFCI rather than make exposed metal parts live.

[ReeceyBurger123]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

if 230v got exposed to the main board, i doubt most of the low-voltage side of the set is still working. Are you sure you weren't testing incorrectly? Note this set has an earthed chassis so any short to the chassis should trip a household gfci rather than make exposed metal parts live.

+1

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

If 230V got exposed to the main board, I doubt most of the low-voltage side of the set is still working. Are you sure you weren't testing incorrectly? Note this set has an earthed chassis so any short to the chassis should trip a household GFCI rather than make exposed metal parts live.

This is how i checked per first post - used DMM on the test points with one probe, the other on the chassis and turning on the set with the remote.

Since the 230V was removed from the co-ax the set has no been tripping the ECB. There is sound just no picture.

[necstandards]

Re: Samsung PS51E450A1WXXU (Live coax potential cause)

Fitted replacement y main card today and yes tv is working perfect again - happy days!
Before i leave it on too long is there any thing else I need to do, firmware upgrade or the likes ??
Can't say how thankful I am for this forum - just amazed I learnt to fix my own tv.. thanks so much