Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
Found the right schematic in a different service manual, the one for for PZ70. It looks like this pin with the low resistance goes to the Out1 pin on the IC. Tracing this back it looks like this is the pin that feeds the line that is broken or has a defect in the display. I guess I write off this TV as having a bad display panel. What a shame, just a bit over 5 years old on a $1000.00 tv.
PS: Found several pins coming from the same IC that are very low resistance....
chiefk
Member
Last Activity: 09-28-2013, 08:56 AM
Joined: 09-24-2013
Location: Crestview, FL
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
My board is a TNPA4383 and it does not have the high voltage screw. So I checked it from pins A1 of the input to all the pins on the ribbon connectors. all open. Then I checked from B40 input to all the pins on the other ribbon connector. Everything was open except for A1 on the ribbon for SU13. It was 18 ohms on one board and 8 ohms on the other. The schematic in the service manual is for a different number su board but it looks almost the same.Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
I did ask him specifically if it came out of a cracked screen tv and he said no that it was working. Tom, what do you think the chances are of my display being bad? 100%? Do you think I fried the replacement SU board? Do you know of any way to test the display other than power on?...Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
Do you think I fried the board when I plugged it into what may be a bad or shorted display? I just corresponded with the seller and he assures me that this board came out of a functional TV.Last edited by chiefk; 09-27-2013, 01:10 PM.Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
I can't find any transistors with that number. I have the Pan service manual and it does not list any 2N transistors. What exactly do they do? With the SC board connected and the SU board disconnected the set powers up good. Of course the upper screen is missing.Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
NO, but I will look for them. They are on the SU board?Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
Just received the new used SU board and installed it. Same problem. Disconnected board and set powers up normal and stays on. I guess I got a bad board or there is something really crazy. I even disconnected the 4 ribbon cables going to the display and it does the same thing, 7 flashes of death.Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
OK I checked from chassis ground to all the pins on the ribbon cables using my digital ohm meter. All checked open....Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
After doing a visual inspection on the display panel I found a spot where the lines are broken. It looks like a small cross where there are no lines. What is this? Is this possibly a shorted panel? I am still waiting for my new SU board and I am afraid that if this is a short in the panel I am just going to fry the new board. I tried to take a picture of the defect but it is impossible due to the reflections. When I shine a light on the panel it is easily seen. I estimate the size as .09 wide by .06 up and down.Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
So what you are saying is I should change the SU and see what happens? Maybe waste alot of money. Can the SU be disconnected from the panel side and not damage it?...Leave a comment:
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Re: Panasonic TH-42PZ77U No Pwr, Blinking 7 Times
I have a 42P700U with the 7 blinks. I have gone thru the troubleshooting steps and now with the SU board disconnected it stays powered up. My question is can I hook the board back up and just disconnect the 4 ribbon cables that feed the display panel? I want to make sure it is not my panel that is bad. My thought is if the SU board is in fact defective it will still give me the 7 blinks with the panel disconnected.Leave a comment:
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