Dead Sony KV-1200U

[kx250rider]

Originally Posted by freakaftr8

I have the high pitch whine and audio before the fuse blows again, after i reinstalled the HV rect, Is the HOT one of those 2 transistors in the flyback cage? Both of these NPN sony transistors are C806A.

Q801 is the HOT, and Q802 is the converter; both 2SC806As. I'm looking at the schematic now, and I see 3 mylar caps, and the damper diode (D801) are still in the circuit when the HOT collector is disconnected. I've seen those caps short, but you should see that as a short to ground from the collector. I can't remember if you checked that and said?


The B+ comes from the emitter of Q903 (2SD69). I think that's on a heat sink, mounted on the chassis frame, if I recall (no pic in the book). It's a basic linear supply, with only a bridge, filters, Q903 to regulate, and Q601 (2SC867) as regulator driver. Those short OFTEN! I'd check that first. If it's blown, you likely have a load someplace which blew it.

How about I send you the schematic from the factory book? It's a very small manual, and I think all you need is the schematic and I can include the pages on adjustments. PM if you would like it.

Charles