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Toshiba 42HP95, auto shut down after plug in, PSU fine    
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Joined: 08 Apr 2011
Posts: 2
Location: ks

PostPosted: Fri Apr 08, 2011 11:16 am    Post subject: Toshiba 42HP95, auto shut down after plug in, PSU fine Reply with quote

Have a TV that just one day went into a protect mode of sort with the typical red blinking light. Unplugging seine board did not fix it. I removed loads from the PSU and all voltages are present. One by one, I plugged things back into the PSU looking for something with a short, nothing.

I got everything plugged back in and the sucker worked for 3 hrs. Then just shut off again with the same red blinking light. I monitored voltages during boot up and in protect modes and the PSU is NOT sending out a protect voltage but IS sending out a standby voltage so something else shut the PSU off, likely NOT a PSU issue.

Problem is I cannot find what is shutting it down. The 12v/20V plug from the PSU is the one that has to be plugged in to get the relays to fire on the PSU. That plug works through a sub distribution PCB, then to the "signal board" which looks to be the board with with my processors and such.

I would suspect this board but the fact that there is a red blinking light might be telling me it is detecting something else wrong BUT I have tested with NOTHING but that 12v/20v plug going to the signal board so nothing but power to the board and it still shuts down.

I was testing voltage to the fans and though they are 12v, they are getting about 8.5V, not sure if that is a concern. Also wondering if there is a tach signal from the fans that might be shutting it down.

Bottom like, I it would be dandy if the TV had service codes to help isolate the issue. I would really like to score some good diagrams and service info for this TV.

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PostPosted: Fri Apr 08, 2011 1:13 pm    Post subject: Reply with quote

and such:


Joined: 08 Apr 2011
Posts: 2
Location: ks

PostPosted: Fri Apr 08, 2011 1:31 pm    Post subject: Reply with quote

Thanks! I did download the manuals but they seem to only include board layouts and parts lists. I was hoping they were expansive to include test parameters and voltage ranges.

What I am thinking I might be experiencing is a slight out of tolerance voltage from the PSU that is causing the main board to shut the system down and throw a blinking light. What is the typical tolerance of voltages that the PSUs operate at?

I believe my 12V = 12.55, 5V = 5.15, 32V = 31.50, 20V = 20.6, etc.

I am just curious how far out these might need to be for the main board to shut things down? so far I have the main board connected ONLY to the PSU and low B board and sure seems that the main board is what is shutting it down so it must not be happy about something...
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