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Old 01-03-2007, 02:37 AM
markthefixer's Avatar
markthefixer markthefixer is offline
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Join Date: Apr 2005
Location: Bensenville,Illinois
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Troubleshooting a Sony TV Power Supply from 1999

Has anyone worked on Sony Power Supplies for television sets here? I have a 32" Sony 1999 kv-32s42 find. The power supply uses a dual bipolar transistor design coupled with two transformers and some capacitors to form a power oscillator for developing the B+. It looks like the two NPN transistors , actually it is ONE case with TWO NPN transistors in it, called a mx0841ab-f.

Using EchoWars's transistor diode equivilent test, both read ZERO all six ways each, and on a conventional ohmmeter, I get less than one ohm all six ways each. Looks like they're dead, BUT has anybody done something like this before?

The circuit is common across Sonys, I have a 20" Sony 199(8,9??) tv with the same setup, but a slightly different part number. I also found computer monitor schematics with the same setup. I just don't have the intestinal fortitude to open that set up, remove the similar part and make comparison readings.... (It's my "daily driver").

I also don't like the readings I am getting with the Horizontal Output Transistor, AND upon removal, the heat sink grease only covered the top of the tab area, NOT the body where the heat was produced. No surprises on THAT failure.

I know about the kits for Sony parts from B&D enterprises, which has both the dual transistor and the H.O.T. for about 20 bucks.
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