Panasonic tcp50gt30 7 blinks, help with SU/SD test

[erickeri1234]

To start off I just picked up the tv about two weeks ago. It has a cracked screen which I just got a screen yesterday for $60, (without boards) It does have the 7 blinks of death which I thought was going to be the SC board. I was going to purchase the repair kit but Before I did I wanted to test it first.

So I tested the SC board and found NO shorts. I did look on here for testing the SU and SD buffer boards. I removed the 4 screws holding the SU/SD to the SC board, I removed the 3 connections from the SC board.

The TV does power on NO blinking red lights, The green LEDs on the boards light up and the fans come on. But I hear a pretty loud buzzing noise from the SC board. Which I think is going to be normal. Cause the SU/SD boards are disconnected.


I'm trying to figure out which board is bad! Im not sure But I think I both the SD/SU boards are bad. I tried to test them separate but I think Im doing it wrong.
Whats the best way to test the SU/SD?

Thanks Eric

[ERICSSON89]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

please upload photos of the chassis with the back cover over and also separate photo of the SC, SU/SD BOARD. remember good clear pictures are needed.
ERIC

[erickeri1234]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

Here are some pictures

[freakaftr8]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

usually if somebody powered up the TV with a cracked screen 9 times outta 10 I have seen buffer boards short so expect to see a shorted buffer board upper or lower or both

[electronicsurplus]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

How are the buffers tested? Many people have asked where to find VF-Gnd?

[tw2005]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

How are the buffers tested? Many people have asked where to find VF-Gnd?

VF-gnd is usually labelled vfg or tpvfg. Find the applicable manual in pdf and use the find function with key word vfg. If you can read schematics and block diagrams I reckon you'll work it out.

better still look at the buffer and you can see how they mount to the Sc board. Vfg is floating ground not chassis ground.

As for testing, quick test would be vfg to the outputs in continuity, should not show short.

For resistance testing, you'd have to find the applicable training guide of that series but not all guides have that info
VF5V, VFO & VSCN_F are usually the ones to resistance check but I found if the buffer is shorted VFO is always short to vfg

[electronicsurplus]

Re: Panasonic tcp50gt30 7 blinks, help with SU/SD test

I test using ground point on connector to ribbon cable, with meter set to diode mode, using +(Red) on ground point on connector and -(Black) lead testing each pin on connector going to ribbon cable, for continuity making certain that each are more than 700 Ohms. There are no shorts. Does the test mentioned test different parts of the buffer or the same?