Film-Tech Forum ARCHIVE: Sound Failure in CP55/analog reader

This is topic Sound Failure in CP55/analog reader in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jeff Lacey (Member # 3217) on 04-10-2006, 05:36 PM:

Hi everyone... I have a problem with a CP55. The issue is that the sound will drop out at random times throughout a movie, and sometimes not at all. Bypass mode does not restore the sound either. Nonsync works.

I am getting no signal on the preamp card, so I replaced it with two other cards, and still have the same problem. I have also switched out the voltage regulator, with the same results.

I am thinking that this is not a problem with the CP55 at all, but is in the Kelmer analog reader, but I wanted to confer with you all to see if there was something else I could check. My next step is to replace the reader with a known working one to see if the problem will follow.

Any help you can give me would be greatly appreciated.

Thanks!

Posted by Louis Bornwasser (Member # 3063) on 04-10-2006, 06:30 PM:

There are many possible causes; try the analogue power supply first (Kelmar). Can you substitute another from another screen? Louis

Posted by Jeff Lacey (Member # 3217) on 04-10-2006, 06:38 PM:

That's my plan right now...

The reader is on when we lose sound, so that was why I was thinking it was in the processor at first. Now I am pretty confident that its the reader....

Posted by Dominic Espinosa (Member # 2122) on 04-11-2006, 01:53 AM:

Could be a broken or loose connector/solder connection/wire?

Posted by Michael Schaffer (Member # 1204) on 04-11-2006, 03:26 AM:

Loose wiring sounds like a probably cause. More likely at the reader end because of the vibrations of the projector. There isn't much movement in the sound rack. If you can reproduce the problem, you can play the Dolby tone loop and follow the signal with your multimeter to the processor inputs.
Be warned that you can't simply swap the readers. They need to be aligned.

Posted by Jeff Lacey (Member # 3217) on 04-14-2006, 02:56 AM:

Hey... Just a quick update... I switched out the reader's power supply with a known good one.

The problem hasn't followed to the new house, and the problem house hasn't had any issues either...

Maybe the contacts were just dirty?

Posted by Jason Miller (Member # 2341) on 04-14-2006, 03:39 AM:

If it is the Vanilla colored box with the Green LED ont he front, I have had the same intermittant problem.

as soon as I show up to the theatre it seems to be working fine.

I have been replacing those older Kelmar power supplies with the new black ones that have LED current adjustment on the front so you dont have to open up the box.