Datasheet

http://www.instructables.com/id/Dell-W5001C-50quot-plasma-fix/
step 4: Debugging on the Bench
More testing in the lab revealed that the problem was a defective IC, U501 which is a Fairchild Semiconductor part KA3883. I ordered a replacement from digikey, 497-
3678-ND , which is a STMicroelectronics UC2843B, for $1.09. The original KA3883 is not generally available(discontinued?). UC2843B is higher quality drop-in
replacement.
The proof that the current mode pwm control chip(KA3883) was the source of the problem came from heating just that part with a hot air pencil and watching the Va
voltage go up to 60V then cooling the control chip(KA3883) with a can of compressed air and watching Va go back to zero. The part is defective and for whatever reason
responds to thermal shock. This could have indicated a cold solder joint but, after checking, the solder joints looked fine. Diagnosis: defective KA3883.
Additional Info:
The power supply board is easily detached by removing about ten philips screws and disconnecting the eight connectors.
If you want to test the board on the bench, away from the rest of the TV), you must use an isolation transformer. Plug in one side of the isolation transformer to the wall
then plug in the board to a suicide cord connected to the other side of the transformer. This is so you don't die.
You also need to know how to turn on the board without the remote control, right? This is done by simply connecting pin 'PS-ON' (found on connector CN8007) to
ground(ie the RTN pin). I used a small jumper to short across from PS-ON to RTN. You can just leave the jumper there and use a power strip to turn the whole thing on
and off.
I traced out much of the relevent circuitry to make sure I knew what I was probing and so I could debug the Va circuit. The excellent layout and silkscreen notation on the
Samsung board was very helpful. The Va circuit is mostly contained within the 500's numbered parts, ie U501, C501, R501, etc. If you are going to probe any of these
parts with the board powered you MUST USE AN ISOLATION TRANSFORMER so you don't electrocute yourself or destroy the board, especially if you are using an
oscilloscope or something that is not battery powered.
Image Notes
1. Isolation Transformer
2. Power strip used as a switch to turn board on and off.
3. Suicide cord
Image Notes
1. AC input header
Image Notes
1. Safe
2. Death
3. Suicide cord
Image Notes
1. Testpoints
2. Va Testpoint: This was the one that was not working.
3. Test Connections for Va. Wires are soldered to the vacant vias and clip leads
are attached to the wires.