denon 3801

I think I was actually the first to suggest a cracked board when you first posted. I would think that the system control micro being faulty, whilst possible, is unlikely. I have a friend who has this "rule" that the more pins a device has, the less likely it is to be faulty ... Just a joke, but actually, not a bad maxim to live your repair life by in practice.

For sure, you could pull every board out and physically examine it, but really, it just wants either fault finding properly, or giving a second opinion by a reputable repairer. The lot you already took it to are taking the piss suggesting $760 to repair it. That actually says that they either can't do it, or don't want to, so are doing the old "price it ridiculously high and he'll walk" trick.

The system control micro area is generally easy to troubleshoot for a fault like this. You only need establish that the 5v supply is good and accurate, the reset line is at the right level, and the system clock is running. After that, you check for activity on the switch matrix lines, in particular, those running to the standby switch. Make sure that they do something when you push the button, preferably right back at the appopriate pins on the micro, but at the switch pins will do at a pinch. After this, if all is well, you would need to check the "power on" line coming back out of the micro, which should toggle as a result of pressing the standby button. There are odd little problems that could throw a spanner in the works of this simplified procedure, but for 99% of cases, those are the checks, in that order, that will establish whether or not there is a sytem control micro problem. However, all this assumes that you have a 'scope to hand, and are able to read and follow schematics and layout drawings properly.

Arfa