The tv powers up just fine but no matter what input source on the back is used (coaxial, rca, HD) the screen is black and says "No Signal". There is also no sound. The menu and service menu can be accessed just fine. I checked the memory for codes and there were none. The person that I got the tv from had it looked at and was told it was a bad signal board. What board is the signal board on this tv and could that be the problem? Could this be the UD board?
Thanks
Jeff Bonk
If you are able, get the service manual, and double check all of the lower voltages going to the video switcher board on the back of the TV set. The fact that you get no signal on any input tells me that your problem is most likely on the switcher board. I doubt that your problem is on the UD board as you stated, that board is only the DVI decoder board and has nothing to do with switching all of the different inputs. My first guess would be the U board or the power supplies that feed the input board because you have nothing. If you can read a schematic and follow circuit flow, i can save you a few bucks and send you the service manual for this TV set if you wish. Good Luck with this repair, and let us know how this repair turns out for you.
Hi Larry,
Thanks for the help. I had a service manual for the set so I started to check the voltages on the U board. I noticed right away that the voltages on IC2001 and IC2002 were all around 20 to 45mV when they should be around 5V. I then checked the 9V on pin C7 at the connector and found only 40mV. I did have 5V on pin C32 and 12V on pin C5 at the connector.
What would be the next step?
Thanks again for the help!
Ok... I think the problem is something on the A board. I checked the 9V source to the B board and it is getting the 9V from the A board. I'm having a hard time reading the schematic to trace where the 9V circuit on the A board is losing the 9V to the U board.
Any suggestions?
Thanks!
Larry,
I found the culprit. The "IC Protector" PS2 was blown. Just for a quick check, I jumped it and the tv worked fine. Should I be looking for something else that caused this to blow?
Thanks a lot!
Yes for sure, what is the PS2 for, what voltage source? Then I can give you a better idea.
The PS2 is for the 9 volt supply for "9V-3" on the A board.
Any suggestions?