Hitachi 42EDT41 No Picture

[CraigR]

Hitachi 42EDT41 Plasma Has amber standby light push power button and it turns green and I can hear solenoid click in back but nothing on screen. I checked VS and VA voltage and VS is 3.8V and VA is nothing. I was told the power supply board is new.

[tom66]

Re: Hitachi 42EDT41 No Picture

Check VSAGO, VCEGO signals on connector going to power board (should be labelled.) They must be high (>3V) for it to work.

[CraigR]

Re: Hitachi 42EDT41 No Picture

What stinks is that on the power supply there are no markings next to the connector just what connector number is.

[tom66]

Re: Hitachi 42EDT41 No Picture

Oh, I didn't notice this was an LG panel. 42V6, 2004 panel, 480p... is it really worth fixing? Anyway, try isolating the Y- and Z-sustain boards. See what happens, Vs rises or not?

I have vague recollection of fixing one of these. Top left corner one of the ceramic resistors was open circuit.

[CraigR]

Re: Hitachi 42EDT41 No Picture

Only going to fix if it's cheap. Anyway I did get normal voltage with the Z-SUS disconnected.

[tom66]

Re: Hitachi 42EDT41 No Picture

OK you probably have a shorted Z-sus IPM, I would look for a replacement Z-sus.

[CraigR]

Re: Hitachi 42EDT41 No Picture

Well got the Z-sus and same exact thing $45 wasted any other thoughts?

[tom66]

Re: Hitachi 42EDT41 No Picture

Well, are you sure your replacement Z-sus is OK? Is it shorted? $45 on this TV? I get given these for free in working condition.

[CraigR]

Re: Hitachi 42EDT41 No Picture

I was told it was tested and in working condition. I checked VS and VA to ground and it does not seem to be shorted. Unless you can tell me another way to check.

[tom66]

Re: Hitachi 42EDT41 No Picture

VS/VA bad with Z-sus connected means the Z-sus is short; sometimes the short can be hiding behind a component like a diode and so is not easily visible.

[CraigR]

Re: Hitachi 42EDT41 No Picture

Any point to check directly on the board for a short?

[CraigR]

Re: Hitachi 42EDT41 No Picture

Could a bad panel cause the same issue?

[tom66]

Re: Hitachi 42EDT41 No Picture

Bad panel, I have never heard of it on these.
If Vs/Va is gone when Z-sus is in, the Z-sus must be shorted somehow.
These are very dumb plasmas - almost anything can go wrong on the sus boards and they'll do their darndest to keep working...

[CraigR]

Re: Hitachi 42EDT41 No Picture

Hmmm, would have thought a fuse would blow if something shorted.

[tom66]

Re: Hitachi 42EDT41 No Picture

Fuse will only blow if the current through it exceeds its I^2 * T factor (something like 5 amp will blow a 1 amp fuse in 1 second, 10 amp will blow it in 1/4 second, etc.)

If the power supply can't supply that fault current the fuse won't blow, simple...

[CraigR]

Re: Hitachi 42EDT41 No Picture

so look for another Z-sus board then I guess.

[CraigR]

Re: Hitachi 42EDT41 No Picture

Ended up junking it out after another Z did not fix it.