CP650 issues

[Pietro Clarici]

I know it's a dinosaur, but I'm having a few strange issues with a CP650 and I was wondering if anyone had some tips.

First off, It refused to boot up: red button, dark screen, no response. Looked easy enough: I have two spare PSUs, I installed one of those and that seemed to fix it... for 30 minutes or so, until it turned off again. At this point, it was booting up for a couple of seconds each time, and then cycling back to off.
Ok, could still be a power issue again, to be honest the spares have been on the shelf for a while, so I just replaced the PSU with the other one.
And it worked perfectly... for three hours. Then it died mid-show and when we tried to turn it back on it got stuck on the "loading" screen.
As a last resort I've reseated all of the boards, connectors, and even the EEPROM.
Now in testing with rotating pink noise it *seems* to be fine, but it's only been a couple of hours and I'm afraid it will fail again with patrons in the room.

I'm beginning to think the PSUs could be actually innocent. Any other ideas? Is this a common failure mode? I have another non-working unit an hour from me (does not boot, screen lights up with black rectangles all over), could it be worth it to get anyway it and swap one of the boards? Maybe I could install my EEPROM there, if that's not the actual issue?

[Ryan Gallagher]

Do you use your CP650 exclusively for digital audio processing?

If not, and if you have the auxillary power supply connected they should continue to function in bypass mode for a completely unmanipulated optical stereo print (summed mono output to L+R), only the fader wheel remains working.

No one wants to run a film that way but it might be a possible troubleshooting step? If that is also not working something more critical might be the cuprit of the recurring failures.

Are you able to test any of those presumed failed PSUs on the bench?

[Pietro Clarici]

Yes, it's digital only via a DMA8-Plus, the 35mm projector is not in use anymore. I only have a regular multimeter but I could test the PSUs outside of the unit if I knew the pinout for the three power connectors.
The test points on the front panel should give the same results, right?

[Ryan Gallagher]

Yes, it's digital only via a DMA8-Plus, the 35mm projector is not in use anymore. I only have a regular multimeter but I could test the PSUs outside of the unit if I knew the pinout for the three power connectors.
The test points on the front panel should give the same results, right?

Yes you should be able to probe the PSU voltage rails from the test points without removing it. Here is the relevant manual section:

650_power_metering.jpg

I don't have enough experience to know if they should probe valid regardless of the standby/off state. I expect the mains power won't probe anything when off, but it might probe something when in your failed state. I've got one in the closet here I could check in a few.

[Pietro Clarici]

Thanks. I have two other working CP650s there, I can cross check with those.
I was right not to trust it though, I was running a Python script checking it every 5 seconds and it just went offline after 2-something hours of rotating pink noise.