Film-Tech Forum ARCHIVE: I'm sure you have all had days like this

This is topic I'm sure you have all had days like this - CP65 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Eric Robinson (Member # 2966) on 07-17-2007, 10:29 PM:

It started with the upgrade for dts processors to ....043

I went to the theatre.

Masking tape on DTS XD10 "Doesn't work"

I boot it up....Initializing...

Called DTS sorry this is not a field repairable problem.

OK...Installed new DTS XD10 upgraded to ...043

Everything is great?? Whats this..no sound when trying to set
pink noise levels from DTS processor?

Thats OK I have a Dolby CP65, I'm sure this is an easy
solution. Remove CAT 150, put in Cat85 (pink noise generator)
hmmm...sounds pretty good. DTS unit is now working. DTS unit
is outputting pink noise into 6 channel audio input on CP65.

Set all channel levels from Cat85. Set all output levels from
DTS XD10.

Life is grand!

Remove Cat 85, install CAT 150.

Turn CP65 back on.

What?? Wheres my sound from Digital?

Several undocumented steps later and about 4 hours.......

Note that CP65 only produces sound when pink noise card is inserted
but not CAT150.

Suspect that CAT150 is causing some type of failure in CP65.

Reference shematics and note that regulator CAT 249 supplies 24 V to Cat 150.

Note during power up that LED on CAT 249 for 24 V looks dim when CAT 150 is
inserted.

Noted that Cat 249 24 V LED looks fine during power up with pink noise card
inserted.

Noted that banging on back plane around femake connector for control card
causes processor to start working. Keeps working when pink noise card is
inserted works for about 20 seconds when CAT 150 is plugged in.

Concluded that CAT150 is drawing more current than CAT85. Assume that regulator
CAT149 is incapable for some reason of supplying correct power and must be running
in bypasss mode.

Run 69T film in projector with CAT 150 plugged in. Hear Dolby tone in all formats
selectable from front panel including non sync. Hmm... this is odd?

Banging on backplane with screwdriver yeilds repair with Cat85 plugged in.

Banging on backplane with screwdriver yeilds about 10 seconds of normal operation
with cat 150 plugged in before audible relay click cuts off sound.

Conclusion...voltage regulator is unable to meet the current demands of CAT150.
Voltage regultor card is causing CP65 to go into automatic bypass. Voltage regulator
card is dysfuntional.

Any ideas or opinions?

Posted by Monte L Fullmer (Member # 2797) on 07-18-2007, 01:44 AM:

checked traces on the backplane for any breaks in the solder connections?

Maybe a new backplane is in order...

good luck on this one .. - Monte

Posted by Mark Gulbrandsen (Member # 72) on 07-18-2007, 08:45 AM:

I've had the regulator card fail a few times over the years on both 55's and 65's. It happens.

Mark

Posted by John Hawkinson (Member # 1135) on 07-18-2007, 12:12 PM:

When we had a 249 fail in our CP65, it had char marks on it (still worked though, just not so well). Something to look for...

--jhawk

Posted by Louis Bornwasser (Member # 3063) on 07-18-2007, 12:21 PM:

The 249 card has too low of a output current for a CP-65. You will require a 249a which has considerably more current output. The 249 was barely adequate for an unmodified CP-55; running at 99.5% of rating. Add SR and 150 card and you are over. Louis

Posted by Ken Lackner (Member # 1002) on 07-18-2007, 01:16 PM:

If the pink noise works whith teh Cat. 85 card in place but the processor doesn't work normally with the Cat. 150, have you tried swapping the Cat. 150?

Posted by Eric Robinson (Member # 2966) on 07-18-2007, 09:53 PM:

Not yet.
Good information on the 249 and 249a.
This unit has a CAT224 and 2 CAT300's.

I'll publish my fix when I find it.

Posted by Brad Miller (Member # 2) on 07-25-2007, 07:47 PM:

Swap the cat150 entirely or replace the bad diode on the control line of the cat 150. Look at the D403 or the DZ405 diodes.