Panasonic Plasma TC-P46ST30 Does the power supply stay up with SC board disconnected

[jcamerox]

I know I have a problem with the SC board, 4 transistors and 2 diodes are bad causing a short to show on the Vsus connector. The SC board is the only one showing a short on the Vsus supply, so with that disconected from the power supply, shouldn't the power supply stay up?

With the SC board disconnected, and I apply AC, a relay clicks and then when I push the power button the power supply starts up, LED is solid red, Vsus rises to 215 v and then a relay clicks within about 2 seconds, Vsus starts to drop and the LED starts blinking 8 times.

Is this normal for the power supply? I don't want to fix the SC board and then find the PS is also bad.

[tw2005]

Re: Panasonic Plasma TC-P46ST30 Does the power supply stay up with SC board disconnec

I know I have a problem with the SC board, 4 transistors and 2 diodes are bad causing a short to show on the Vsus connector. The SC board is the only one showing a short on the Vsus supply, so with that disconected from the power supply, shouldn't the power supply stay up?

With the SC board disconnected, and I apply AC, a relay clicks and then when I push the power button the power supply starts up, LED is solid red, Vsus rises to 215 v and then a relay clicks within about 2 seconds, Vsus starts to drop and the LED starts blinking 8 times.

Is this normal for the power supply? I don't want to fix the SC board and then find the PS is also bad.

that is normal, make sure you check the sd/su for shorts as well prior to running it after sc repair

[jcamerox]

Re: Panasonic Plasma TC-P46ST30 Does the power supply stay up with SC board disconnec

Thanks very much for the reply tw2005. I'll double check the sc/su boards and then go ahead with the repair.

[jcamerox]

Re: Panasonic Plasma TC-P46ST30 Does the power supply stay up with SC board disconnec

I bought a repair kit from "ShopJimmy", TNPA5351 SC board repair kit as it contained the 2 diodes and 4 Transistors that I needed. The board was assembled with lead free solder so needed a lot of heat to desolder the components, they all looked like power transistors. I only used a 35 w Weller soldering iron with a chisel tip but I used lead/tin solder to re-attach the components so it didn't need as much heat. The kit also came with 4 resistors and screws with lock washers to attach the board. The resistors on the board were okay so I left them. A theory is that the attaching screws work loose over time and that causes an intermittent ground which blows the components. The board was torqued down securely with the lock washer screws. I had checked the SD and SU boards for shorts and seeing none I fired it up and SUCCESS.

It has been running for about 8 hours now and seems fine. I'll let it run for another couple of days before I replace my 42" Panasonic plasma with it.

[tw2005]

Re: Panasonic Plasma TC-P46ST30 Does the power supply stay up with SC board disconnec

I bought a repair kit from "ShopJimmy", TNPA5351 SC board repair kit as it contained the 2 diodes and 4 Transistors that I needed. The board was assembled with lead free solder so needed a lot of heat to desolder the components, they all looked like power transistors. I only used a 35 w Weller soldering iron with a chisel tip but I used lead/tin solder to re-attach the components so it didn't need as much heat. The kit also came with 4 resistors and screws with lock washers to attach the board. The resistors on the board were okay so I left them. A theory is that the attaching screws work loose over time and that causes an intermittent ground which blows the components. The board was torqued down securely with the lock washer screws. I had checked the SD and SU boards for shorts and seeing none I fired it up and SUCCESS.

It has been running for about 8 hours now and seems fine. I'll let it run for another couple of days before I replace my 42" Panasonic plasma with it.

nice, not bad for self repair, they don't always end up easy but it's nice when they do. I hope the solder flowed under those smd transistors. 35watts seems a little light but if it worked, it worked.