Hitachi P50S602 Plasma Power Supply Testing?

[Robb]

Does anyone know how to test a power supply? My TV turns on then back off again within a few seconds. I don't think it's the Y-SUS as it produces a picture before it shuts down and disconnecting the Y-SUS and X-SUS doesn't allow TV to stay on. Any suggestions will be greatly appreciated, there seems to an internet blackout on this issue.

[tom66]

Re: Hitachi P50S602 Plasma Power Supply Testing?

Do you see a PS-ON, RL-ON and/or VS-ON labelled pin on connectors on power supply board?

[Robb]

Re: Hitachi P50S602 Plasma Power Supply Testing?

No, other than the power in, the connectors are CN23, CNPPS & CN06, as follows:

(from top to bottom)
CN23 - Va, Va, NC, Vcc5.1V, GND, GND, GND, NC, Vs, Vs

CNPPS - AUDIO 17V, AUDIO GND, +17V, GND, +5.6V, +5.6V, GND, GND, STBY5V, GND, AC CLOCK, POWER1, POWER2, AC OFF, NC

CN06 - Vcc1.5C, GND, Vra, Vrs, Vcego, Vsago, AC OFF

[tom66]

Re: Hitachi P50S602 Plasma Power Supply Testing?

OK, I think the signals are POWER1, POWER2, Vsago, Vcego.
You want to have the power supply connected and power the set up, check the various voltages on these pins, and see how they change when the power button is pressed. If they drop out, then the power board is probably OK and the main board is shutting down.

[Robb]

Re: Hitachi P50S602 Plasma Power Supply Testing?

When I press the power button, the connections go from 0V to as follows:

POWER1 - 4.3V even after fans stop (shuts itself off) MAIN
POWER2 - 3.2V even after fans stop (shuts itself off) MAIN
Vcego - 3.0V until fans stop then 0V LOGIC
Vsago - 3.0V until fans start then 0V LOGIC

I could not read the connections from the PSU Board so I read them from the MAIN & LOGIC Boards.

[tom66]

Re: Hitachi P50S602 Plasma Power Supply Testing?

OK, this indicates the logic is shutting off the power, which is likely because it detects a fault on either YSUS or XSUS board.

[Robb]

Re: Hitachi P50S602 Plasma Power Supply Testing?

So, if the YSUS or XSUS is faulty, the display can still work briefly (black background with multicolored pixel static/snow).

I have disconnected the cables between PSU & XSUS and then XSUS & YSUS, but it still won't stay powered on. I also disconnected the Y-Buffers and same thing. Not sure how to locate the source of the problem.

[tom66]

Re: Hitachi P50S602 Plasma Power Supply Testing?

I have no experience with Hitachi plasmas, but pink snow makes me thing more of a YSUS than XSUS, if that helps...

[Robb]

Re: Hitachi P50S602 Plasma Power Supply Testing?

Thanks for helping me rule out the PSU! You are the best!