TC-P42X60 blinks 7 times?

[paulstef]

No picture whatsoever. PFC and boost starts, 390VDC.

Output voltage Vsus 180VDC.

5V and 15V from PSU ok. Then MAIN_ON signal from mainboard to PSU turns off and 15V, Vsus and PFC are switched off after 3 seconds then the front LED blinks 7 times.

Removing the cable from Vsus doesn't make a difference. Anyone knows what the 7 blinks mean? :-/



Thanks

[newtothis]

Re: TC-P42X60 blinks 7 times?

What ohm reading do you get on the 15v to ground?

[paulstef]

Re: TC-P42X60 blinks 7 times?

What ohm reading do you get on the 15v to ground?

About 11.3k

[newtothis]

Re: TC-P42X60 blinks 7 times?

Ohms across SN board input?

[paulstef]

Re: TC-P42X60 blinks 7 times?

All major semiconductors on the TNPA5830 seem to be ok.

The mainboard apparently waits for some kind of signal from I don't know where, doesn't get it and decides to turn off the PSU.

[paulstef]

Re: TC-P42X60 blinks 7 times?

Ohms across SN board input?

Yes , the 15V line goes to SN20. It's TP7 on the back of the board. 11.3k from TP7 to Gnd.

(I had it first measured on the PSU to gnd)

[newtothis]

Re: TC-P42X60 blinks 7 times?

7 blinks Driver SOS 2 SU / SD / SS Boards (SC floating voltage area)

Have you isolated board by board until the 7 blinks has changed?

[newtothis]

Re: TC-P42X60 blinks 7 times?

I do know these sets suffered a bit with cold solder joints.

Is there any fluctuation in VSUS when the set is powered?

Any flash at all from the screen?

[paulstef]

Re: TC-P42X60 blinks 7 times?

No light at all from the screen, total darkness.

VSUS fluctuates a bit.

You mean cold solder joints where? Do you have an idea what the 7 flashes mean?

By the way, when I remove the flat cable from the TNPA5830 board the TV doesn't start up at all.

[newtothis]

Re: TC-P42X60 blinks 7 times?

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7 blinks Driver SOS 2 SU / SD / SS Boards (SC floating voltage area)

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PSU usually has bad solder joints.

I am sure Tom has dealt with a few of these sets in his time, He may have some more insight into it

[paulstef]

Re: TC-P42X60 blinks 7 times?

It sounds as if you were assuming this is an old set. :-) It isn't. It's a July 2013 model.

[newtothis]

Re: TC-P42X60 blinks 7 times?

Nope made no assumptions.

Though didn't ask the obvious, Are the Green LED's on the SD and SS boards illuminated?

[paulstef]

Re: TC-P42X60 blinks 7 times?

There are no LEDs. Is it possible you are referring to a different model?

Please have a look at the first picture I posted.

[paulstef]

Re: TC-P42X60 blinks 7 times?

Ok, found the service manual. Not very complete though. But the problem seems to be coming from the SN board indeed.

And, actually there IS a LED on the SN board and it does not turn on.

[nicholas1110]

Re: TC-P42X60 blinks 7 times?

Hello,
These models suffer from the dreaded screws loosening up and causing the sn board to short. Whole sn boards are inexpense, but I suggest you add screws with locking washers to prevent future failures.

[paulstef]

Re: TC-P42X60 blinks 7 times?

I know this problem from another model but this doesn't seem to be the problem here. The contacts are all clean, no arcing. No shorted IGBTs, diodes etc.

[nicholas1110]

Re: TC-P42X60 blinks 7 times?

Have you checked the buffer ic chips for shorts?

[newtothis]

Re: TC-P42X60 blinks 7 times?

Have you checked the buffer ic chips for shorts?

Would most likely see shorted IBGT's if the Buffer IC went

Though worth checking

The SN boards for these are so cheap (around £10 GBP) it is more cost effective to replace the board over repair most of the times. You can get the entire board set for around £50 GBP!

[paulstef]

Re: TC-P42X60 blinks 7 times?

A few outputs of one driver are shorted. I cut the 5V power trace to the defective one (it's the farthest away from the 5V power supply) to see if the rest would work, but it doesn't. Maybe it checks somehow if the chip is there.

Anyway a new chip seems to cost about $15 + shipping, while a used board costs about $40 shipping included. Still pretty exepensive. I would have preferred to replace the chip.

I have several AN16628A from another board but mounted are AN16632A. Who knows what the differences are....

[newtothis]

Re: TC-P42X60 blinks 7 times?

http://www.ebay.com/sch/i.html?_from...A5830&_sacat=0

It is less than $40 to ship one from over there to me in UK