[SOLVED] Yamaha RX-V659 Processor not running but looks alive.

[Yoritomo]

Hello everyone.

I am facing a problem with the processor of this amplifier, in normal condition it is not oscillating, when I set the reset pin low (normally high) the processor is oscillating normally after disconnecting the reset circuit , when releasing it comes high again and the processor stop oscillating.

All power lines looks ok, VSS also, I am not so clever in processors and micro-controller topics, but I have solid experience in electronic repairs.
One thing I noticed is the reset circuit cycling and constantly send a reset, I could not find the reason testing the components around the reset circuit itself.

The schematic can be found here on the website of Electrotanya https://elektrotanya.com/showresult?...a=All&kat2=All.

Thanks for you help.

 

[Yoritomo]

I finally found what was the problem, that is weird. I found a non polarized capacitor , C654 which was normally 22nF which dropped to 4.5nF which caused that the power could not insure to supply the correct tension for the chip IC652, a cmos 4013. After replacement with a 400V equivalent , everything works normally again. That was the reason the reset circuit was dizzy , also S10 was abnormal.