P10 odd problem
2011-04-27 by Frank Simon
Guys,
It's late and I'll try to be coherent discussing my findings working on this P10. So not to type I copied an analysis from a gentleman named John Gee because he wrote a nice failure analysis and it is identical to mine:
The synth lights up but does not play. It will tune and boot; LEDs light and switches respond; program numbers change, etc. The LEDs and program number readout all flicker in sync, like they're pulsing. No sound is produced when I play the keys. At one point, all lights went out except the tune light; lights did not return for several seconds, so I powered down; hen I powered back up, the LEDs were back, switches responded, etc.
So I got back into it and have some odd reports. I made a repeatable correlation with a symptom. When I have the hood open, it would boot up and light up but as I closed it, it would reboot or go to retune. It was literally about six inches from closed that when it rebooted. So if the hood was open it seemed to function. So I'm thinking mechanical movement of cables etc but that is not the case. I have everything unplugged but the PCB3 board and as I lower the hood it repeatably reboots just as the hood is about closed. Now I am grasping at straws thinking EMI with proximetry of clock or uP right above transformer. Is this crazy? I do hear the transformer hum but all my supplies are good. This is very repeatable. Crazy huh?
Frank
It's late and I'll try to be coherent discussing my findings working on this P10. So not to type I copied an analysis from a gentleman named John Gee because he wrote a nice failure analysis and it is identical to mine:
The synth lights up but does not play. It will tune and boot; LEDs light and switches respond; program numbers change, etc. The LEDs and program number readout all flicker in sync, like they're pulsing. No sound is produced when I play the keys. At one point, all lights went out except the tune light; lights did not return for several seconds, so I powered down; hen I powered back up, the LEDs were back, switches responded, etc.
So I got back into it and have some odd reports. I made a repeatable correlation with a symptom. When I have the hood open, it would boot up and light up but as I closed it, it would reboot or go to retune. It was literally about six inches from closed that when it rebooted. So if the hood was open it seemed to function. So I'm thinking mechanical movement of cables etc but that is not the case. I have everything unplugged but the PCB3 board and as I lower the hood it repeatably reboots just as the hood is about closed. Now I am grasping at straws thinking EMI with proximetry of clock or uP right above transformer. Is this crazy? I do hear the transformer hum but all my supplies are good. This is very repeatable. Crazy huh?
Frank