Resetting Hitachi plasma P42H01UA

[tom66]

I got this plasma recently for repair. It has the common issue of shutting down after 10-15 mins due to cold joints on the power board.

So, as part of my diagnosis, I unplugged the X- and Y-SUS and removed the power board. When I installed it again, I forgot to connect the X-SUS. The TV powered on, but produces only audio and won't switch off -- it looks to be in a lock-out mode of sorts because it's detected a fault with the X- or Y-SUS. Vs and Va never rise; even without the board removed.

So, I need to reset this. But I can't find how. Anyone know?

[tom66]

Re: Resetting Hitachi plasma P42H01UA

The guide in the Hitachi manual
http://electronicshelponline.blogspo...hooting-4.html
about resetting (removing CN68) does -NOT- work on this model or in this case.

I checked, and I have Vcego present (+3.1V) turning on the 5.1V rail, but no Vsago for turning on Vs/Va. So, I decided to unplug CN68 and jumper Vsago, but I did NOT jumper Vcego, just to test the Vs and Va.

I immediately got smoke from the power board upon plugging it in. Uh oh. Turns out, jumpering just Vsago enables the Vs and Va power supplies but does -not- bypass the inrush 10 ohm, 5W resistor with that second relay click. So, loads of current from charging the Vs and Va output capacitors blows up the resistor because of course P = I^2R. Whoops. Repairable, but it's making this TV seem an expensive one... I was brought this to repair, so I don't have anything in it, but still...

It seems like my unplugging of the X-SUS has set some kind of sticky bit in the control board which will not clear, but this seems bizarre. A lesson learned if this is the case!!

Ugh.