LG 42PC1DV no start

[maxvalutech]

This is a low resolution 2007 plasma so not really worth chasing problem too far. It was completely dead but found a swollen 12v cap on PSU and replacing that brought standby red led to life. Press button to start the led turns green then quickly back to red. The following is from main connector (p800) on PSU.
Pin: 3.3on, det, 6v, nc, G, 5sb, 5Mon, 5D, VSon, G, S5v, RLon, ACd.
Sby: *0.03, 0 , 0.23, 3.3, 0, 5, *0.03, 1.24, 0.03, 0, 5, *0.04, 3.10
***these voltages rise to around 5v when on button pushed.
Strangely the NC pin has 3.3v ????
The main board is trying to switch on the PSU outputs but protection circuit kicks in and puts set back to standby. PSU is 2300KEG002B-F(LY) rev 1.3

[Andrew F. Ali]

Re: LG 42PC1DV no start

Take two (2) 120Vac 60W light bulbs and connect them in series, to make a test lamp. Disconnect ALL connectors on the PSU to the Main and other boards. On the PSU P800 connector, Using a 1k ohm resistor connect across 5sb and 5Mon pins. Taking another 1k ohm resistor connect it across the 5sb and VSon pins. Taking yet anther 1k ohm resistor connect it across the 5sb and RLon pins and finally, take a 4th 1k ohm resistor and connect it across the 5sb and 3.3on pins. So you now have four (4) 1k ohms resistors soldered on the 5sb pin. Connect now the test lamp across VS and GND. Make sure your connections are secured, insulated and not touching anything to short-off the PSU.
Plug the PSU into the ac. If the PSU is good the test lamp should come on and light up bright, and stay on. Measure the VA voltage. see if it matches the expected voltage on the sticker. If it does this proves your PSU is good. Any deviation from the expected would suggest the PSU is bad. GOOD LUCK.

[maxvalutech]

Re: LG 42PC1DV no start

Thanks for the good luck which duly arrived in the form of a similar LG plasma, only a year between them and while Y and X a bit different the PSU was the same. My testing convinced me the PSU in this set was bad so swapped them over as other set had Y side problem. All voltages came up and Vs Va spot on. An acceptable picture produced and tested for several hours now. These old sets test you out - heavy as lead, hard to reach boards (except PSU), and screws and more screws!!

[Andrew F. Ali]

Re: LG 42PC1DV no start

Good to hear!!...OK so we could probably look at fixing the other TV now. Keep the info on Post 2 for future reference.