Hitachi 55HDT52 - VCEGO/VSAGO ON for 2 seconds

[drpj23]

I have been working on this thing for some time now only to be baffled.

The symptom as stated above, is that the Vs and Vc commands only come on for a brief second or two only to collapse back to the mV range.

With the sustains disconnected, it still does this.

I have, over time, replaced the power supply, main, digi-main, and logic board. And it still is sensing trouble.

Upon clicking on, the green light flashes 10-12 times then to a steady green light. Eventually it will turn orange.

The digi-main does a little sequence that lasts about 10 seconds and then shuts off. I am wondering if I got a bad logic board or what.

I do believe there is another post about this TV but his/her commands were constantly on.

[Dennis H]

Re: Hitachi 55HDT52 - VCEGO/VSAGO ON for 2 seconds

Remove the upper and lower buffer boards from the Y sustain.carefully. Unplug it from the wall for 20 minutes or so OR unplug and replug CN68 flat wire to the logic board.

Then, without the buffer boards in, but with the Y sus properly connected to the X and thus the Main, power up. You should be able to see Vc and Vs on the pins going into the Y sus (yellow flat cable top of board). If you do, and if it stays up, ie, no self protect mode, start checking those buffer boards.



The TV is going into self protect mode. probably due to a short somewhere, in the X Y or buffer boards. Mine was a blown buffer chip... M810 on the lower buffer board. You can check each buffer chip (IC) for continuity and compare. Chances are, you will have one that is grounded.

[drpj23]

Re: Hitachi 55HDT52 - VCEGO/VSAGO ON for 2 seconds

Wow, you were right. I found 1 buffer IC (cant remember where right now but it was on the upper buffer) that was bad.
Though, I still don't know why I couldn't get the voltages to be present without the sustain boards plugged in, suppose there is some type of feedback.

Anyways, know of a good product for that silicon around the chips?