Hey guys.. looking for some input on this LG 60PV450 plasma
So, initial problem was there was no picture but sound could be heard. Popped it open and looked around for bad caps, didn't see any, they all looked pretty good. No problem there.
Tested all fuses for continuity, found that the fuse on the Zsus board was blown so I removed and inspected both sides of the board. Found also that out of the 3 huge copper inductors, one of the solder joints came loose along with some heat damage. Moreover, the other 2 inductors seemed to have cracked solder joints.
So I cleaned up the burnt solder joint and resoldered all the points to the inductors along with replacing the fuse with the same type (T6.3AH 250V).
Reinstalled the board and connections and turned it on. Still no picture but then came the click, click, click sounds from the relays. The TV would go right back to standby mode.
Disconnected the Zsus board connections, both from power supply and flexible cable from control board. Connected the test pattern jumper and removed the flexible cable from the main board to the control board. Turned it on and was able to get the test pattern to display.. of course it was a red and distorted tint as usually seen from a disconnected Zsus board.
Next, I removed test pattern generator jumper and reconnected the flexible cable from the main board to the control board. Turned it on and was able to get the regular picture display of channel, inputs, etc. (still no Zsus connected, red and blotchy display)
At this point I decided to test the voltages at various points on the Power supply and Ysus board.
Factory Voltage settings:
Va = 55V
Vs = 201V
-Vy = -178V
Vsc = 150V
Vzb = 110V
What I measured:
Va = 55V
Vs = 202V
-Vy = -178V
Vsc = 150V
Testing the Vzb is where my next problem is because once i reconnect everything on the Zsus board, it quickly goes back to the no picture, repeated clicking and standby mode. Holding my meter on the Vzb test point while turning it on also reads no voltage.
I'm almost certain the Zsus is bad but am not sure about the Zsub also.
I've been studying the past 2 days to try and give as much information as possible. I have a background in electronics but this is my first time delving into a plasma TV. Any more suggestions on test procedures, something I missed or a diagnosis would be much appreciated, Thanks!
~Dave
So, initial problem was there was no picture but sound could be heard. Popped it open and looked around for bad caps, didn't see any, they all looked pretty good. No problem there.
Tested all fuses for continuity, found that the fuse on the Zsus board was blown so I removed and inspected both sides of the board. Found also that out of the 3 huge copper inductors, one of the solder joints came loose along with some heat damage. Moreover, the other 2 inductors seemed to have cracked solder joints.
So I cleaned up the burnt solder joint and resoldered all the points to the inductors along with replacing the fuse with the same type (T6.3AH 250V).
Reinstalled the board and connections and turned it on. Still no picture but then came the click, click, click sounds from the relays. The TV would go right back to standby mode.
Disconnected the Zsus board connections, both from power supply and flexible cable from control board. Connected the test pattern jumper and removed the flexible cable from the main board to the control board. Turned it on and was able to get the test pattern to display.. of course it was a red and distorted tint as usually seen from a disconnected Zsus board.
Next, I removed test pattern generator jumper and reconnected the flexible cable from the main board to the control board. Turned it on and was able to get the regular picture display of channel, inputs, etc. (still no Zsus connected, red and blotchy display)
At this point I decided to test the voltages at various points on the Power supply and Ysus board.
Factory Voltage settings:
Va = 55V
Vs = 201V
-Vy = -178V
Vsc = 150V
Vzb = 110V
What I measured:
Va = 55V
Vs = 202V
-Vy = -178V
Vsc = 150V
Testing the Vzb is where my next problem is because once i reconnect everything on the Zsus board, it quickly goes back to the no picture, repeated clicking and standby mode. Holding my meter on the Vzb test point while turning it on also reads no voltage.
I'm almost certain the Zsus is bad but am not sure about the Zsub also.
I've been studying the past 2 days to try and give as much information as possible. I have a background in electronics but this is my first time delving into a plasma TV. Any more suggestions on test procedures, something I missed or a diagnosis would be much appreciated, Thanks!
~Dave
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