Cyrus 3 Schematics

CYRUS 3 HA7A Schematic

Hallo,
i'm repairing CYRUS 3 HA7A3124 (date 9311)
Transistors in L final stage and driver was burned.
With new transistors sometimes OK,
sometimes on output occures -12 to -20 V DC.
Also in stby, CCS off, LED pwr flashes orange.

Schematics from Tenson are for CYRUS HA7Z.
HA7A ist different. Final stage quasi complementar,
CPU 40 pins DIL, diffferent numbers of components.

Please, has anybody the right schematics for me?

Thank you, Ladislav

 

Problem solved

With removed final transistor still orangre flashing LED PWR and -20V on output.
Defective was SMD transistor T539.
Short protection was permanent activated and over R614 and T539 came
-20V to output. (Without loudspeakers.)

I've T539 replaced, though i think, it has no function in this circuit.
Transistors T539 and T541 should work as a thyristor.
Whenn one transistor switches, output current holds both transistors
permanently in switched status. (Till energized)
But here is output current limited by R614 to maximal 0,86 mA.
Ube of T541 on R523 and R525 parallel is under 0,2 V.
Si transistor needs minimal 0,6 V.

Ladislav