Denon AVR-X1200W repair help

[elnaldo]

By now you just need to figure why the "mainpower" signal is not present. If the microprocessor is receiving voltage or not, and then figure if it's working as it should.

I'd check all the "standby" voltages are there.

 

[Gl-dunk-27]

Yeah, I was checking around that area for the voltages. IC751 does seem to receive 3.3V and CN753 does have 3.3V at pin #2. See attached image of CN753. Pins 3,5,8 (my numbers) are 0 and the rest are 3.3V. Also, the volts mentioned on the board (see attached) are also correctly coming when turned on. Couple of other things. IC (F0, N8) shows 5.2V at F0 and 3.3V at N8 pins respectively even on off state. I have also captured voltages for IC732 for on/off state. Will attach in next post. Voltages at couple of smd transistors were 3.3V at center pins but 0 on opposite side for both pins, while for some other transistors (in the pic) it was 5.V at center pin, 5.2V at opposite one pin and 4.6V at the other pin. Also, volts at CN762 were around -2.0V when in on state.

 

[elnaldo]

I'd concentrate by now on the schematic and standby voltages, if they are OK, time to monitor the "mainpower" signal.

It's much easier to read a schematic than a PCB silkscreen.

A microprocessor needs: supply voltage, a "reset" voltage at the reset pin, and a clock signal from a quartz oscillator. If those 3 things are present the IC should be working.

 

[Gl-dunk-27]

Thank you! Couldn’t work on it today. Will checkout tomorrow.

 

[Gl-dunk-27]

Hi elnaldo, couldn’t get to work on for a few days. Have to away for a few weeks and will come back to it. Determined to fix it then with your help. Thanks!