Viera 42 inch LCD,not firing up Looking for a bit of help ..

[ceedy]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Doh! .. i'm making this hard work !!

Shouldn't have rushed the reply before going to the Docs..

I'll start again ..

With power on ..

Cap C835 goes to 18.7 v then back to 0v when off.

C843 goes to 22v then back to and holds 19v when off until plug is pulled then back to 0v.

Can't find a D823 on this board ?..

Just looking for data on Q804 & 805 , on this board they are marked as Motorola 932 1431A

C.

[tom66]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Both those readings are good. What voltage do you see from the primary ground to the B+ (should be 320V in standby, 390V run... though I think 320V while there's a fault.) One place to test it is at JSP826 and the 0.47 ohm power resistors.

[ceedy]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Both those readings are good. What voltage do you see from the primary ground to the B+ (should be 320V in standby, 390V run... though I think 320V while there's a fault.) One place to test it is at JSP826 and the 0.47 ohm power resistors.

At Jsp 826 337v at power up ( used Large cap can as Neg ) relay clicks off decays slowly down.

also 172v relative to chassis .

[tom66]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

337V is fine, you have 240V mains, not 230V, but that's the UK standard.

Can you check if the 0.47 ohm resistors are OK?

If not, I would suggest replacing the control IC.

[ceedy]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

337V is fine, you have 240V mains, not 230V, but that's the UK standard.

Can you check if the 0.47 ohm resistors are OK?

If not, I would suggest replacing the control IC.

They read 2.4 ohms , as they seem to be parallel .

Control IC .. = IC 802 ?

C.

[tom66]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

I guess your leads have some resistance, no problem.

Yeah, IC802 is the control IC.

[ceedy]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

I guess your leads have some resistance, no problem.

Yeah, IC802 is the control IC.

maybe a bit of delay now ,, trying to find one or two in the UK ??
tricky

have good xmas

Chris

[ceedy]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Back again now Xmas is outa the way .

As I could not seem to get a Decent delivery time on these IC's and most suppliers wanted too much postage as well .for only a possible solution .. I found a 2nd user PSU board for £40 delivered. popped it in all is well again .
In our smallish room it nearly gives you a suntan


thanks @ Have a good year all esp .. ..Tom66 !!

Will see you all when the next electodisaster occurs .

[tom66]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Glad to hear you fixed it, thanks for the feedback.

[Krzychu92]

Re: Viera 42 inch LCD,not firing up Looking for a bit of help ..

Sorry for digging, but i have exactly the same situation as ceedy one year ago. Xmas is coming and our tv is broken...

Tv was running normally when suddenly went off and now it isn't working. Led blinks 4 times, my psu unit is tnp 8ep 101. The voltage on C835 and C843 is good - like in ceedy's board. Power resistors seems to be good too - my fluke showed 0.5 Ohm on each and in parallel 0.4 Ohm (i think it's a matter of his accuration). At jsp 826 is ~300V DC (as i have 215~230AC in wall). My readings on flex cable are the same as ceedy


Could this be a damaged control IC? I can buy a one for 12 pounds - but i have to be convinced it will bring my tv alive. I can get used PSU that costs 45 pound. What to do? How to check the ic is working corectly or not? Thanks for giving any information.