Film-Tech Forum ARCHIVE: CP500: Analog goes to right surround

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Posted by German Marin (Member # 918) on 08-12-2003, 08:57 AM:

This is the equipment: CP500 SRD, non X over. The Digital is working really good but the analog has big problems: it's only on the right surround and the C channel has a little hum, so low. I've aligned the LED, checked azimuth, etc, even I changed the LED base, but nothing good happened. I tried changing the cards, I started with 661, then 681, 222SRA and last 675A. Nothing.

Posted by Kris Brunton (Member # 432) on 08-12-2003, 09:48 AM:

What happens when the processor is in bypass? Are the stage channels working in bypass?

The 682 card is the analog output card and handles the switching functions - try swaping this card if you have another processor to do it with

Posted by Mark J. Marshall (Member # 1409) on 08-12-2003, 10:05 AM:

This might sound like a stupid newbie question, but can you verify that no one has modified the config to change the channel configuration around? The software in the CP500 is pretty flexible and I had a few units configured to have the non-sync all go to the left surround only.

The hum may or may not be related to the channel config problem. You say it's very low, it may be there all the time and you just can't hear it as easily when there's information also coming from the center channel. Try switching to non-sync on the processor and unplugging the non-sync inputs to see if the hum is still there. If it is, it's not related to your channel configuration problem.

Posted by Peter Hall (Member # 695) on 08-12-2003, 10:33 AM:

We'e had this - the 675 doing the matrix was faulty. Try swapping this with the eq 675
Peter

Posted by Kris Brunton (Member # 432) on 08-12-2003, 11:21 AM:

Peter said

"Try swapping this with the eq 675"

I can't exactly remember but isn't there a jumper on the 675 card that had to be set for which slot it was installed in?

Posted by German Marin (Member # 918) on 08-12-2003, 12:24 PM:

The problem persist in By-pass. Isn't the 682 common path of all formats? Analog goes from 661, 681, 661, 222SR/A, 675A (J12), then goes to the common path thru 675A (J14), 662 and finally 682. The digital sound is perfect, I guess 682 is working fine (I wish I would be wrong, so I'd find the root of problem). I'll try changing the procesor to a CP65 to check if the problem is coming from wiring (The booth was built 5 years ago) or analog reader.
I'll check the configuration to confirm the selected channels for the SR-A formats are correct. Non-sync is unplugged.
Peter, What the swamp exactly do? I changed the card but nothing happend.
Thanks for your support.

Posted by Mark J. Marshall (Member # 1409) on 08-12-2003, 04:14 PM:

quote:
Non-sync is unplugged.

If you SELECT non-sync (keeping it unplugged), does the hum go away?

Posted by Michael Schaffer (Member # 1204) on 08-13-2003, 01:16 AM:

Try making a few custom formats, like playing the Lt and Rt channels direct and see if it impresses the processor at all. That might help narrowing the problem down.

Posted by Pete Naples (Member # 761) on 08-13-2003, 08:13 AM:

Kris, Kinda!

The matrix and eq slots use the Cat675 set up the same way, and no I can't remember which position it is! It's the Cat675 in the DA20 subsection that's set up differently.

It's amazing the number of 'faulty' Cat675 that can be repaired by moving them to the other slot.....

Posted by Peter Hall (Member # 695) on 08-13-2003, 09:41 AM:

Pete's right - the jumper is the same weather the 675 is used as a matrix or eq card. I believe that the card works a lot harder in the eq position - this might explain why an apparently faulty card can work in this posn..

Pete - have you had a chance to see the Cameo ? Only a start really, but we're fairly happy with the results - screen 2 is a vast improvement (SR and sub). Haven't yet seen the DPI machine - I can wait !

Cheers

Peter

Posted by Pete Naples (Member # 761) on 08-13-2003, 12:31 PM:

If my memory serves me rightly the jumper has something to do with clock speed multiplier. ie The card has two different speeds, one for eq/decode, and the other DA20. Can't for the life of me remember which is which I set them like for like when replacing, although the last ones I got from Dolby came with a crib sheet.

I'm intending to visit the Cameo soon, the EIFF has started so there's loads on all over Edinburgh, and no doubt there will be the usual queue of primadonna directors complaining about nothing and demanding everything! (The guy from a couple of years back complaining that his sound was bas really wound me up, moaned that it sounded harsh and had no surround. He insisted it was played in 05 Dolby SR, when I checked the print I found it was recorded in 01 Mono!)