Yamaha RX-V483 dead.

[ponteley]

Yamaha RX-V483 dead. No 5.5V on secondary.
Tested all fuses, diodes, transistors and caps.
Unsoldered transformer, - seems to ring trough on all coils. Fuses are OK. Primary DC voltage 160V.

 

[ponteley]

 

[ponteley]

I suspect 3A453 IC, but I can't find replacement anywhere.
Please help.

Thank you.

 

[PETERDECO]

The STR3A153 is readily available and has the same pinout and similar spec's. If it is the trouble, it might be the only way to save the amp.

 

[Alec_t]

Does the relay pull in?
The board is discoloured below the big primary cap, suggesting overheating. Did you measure the ESR of that cap?