Film-Tech Forum ARCHIVE: CP65 Analog sound problem

This is topic CP65 Analog sound problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Magnus Blomberg (Member # 3463) on 11-17-2005, 03:28 PM:

I have a CP65 where the DTS sound is very low but come from all channels with a slight distorsion. The bypass work prefectly ok. When switching to optical sound, or Mono, there is no sopund at all. I am a little stunned with this and dont know where to start to find the problem. Any suggestions would be highly appreciated.

Posted by Brian Guckian (Member # 1678) on 11-17-2005, 05:14 PM:

Welcome to Film-Tech!

Is your Cat. 240A optical pre-amp card functioning? Do you have a spare?

That might be the first port of call. Also check your Cat. 242 B-chain card, as that may be at fault as well.

Check also your power supply indicators are all OK.

Posted by Gordon McLeod (Member # 33) on 11-17-2005, 05:25 PM:

First did it ever work right or did this just happen if so did anything change
Try switching to bypass is there sound
My bet is the output card or the bypass relays if it is a new problem

Posted by Magnus Blomberg (Member # 3463) on 11-18-2005, 04:09 AM:

Brian

Yes, I beleive the 240A is working. I have tried with a spare 240A and there is no change. Dolby A still not working. The signals to ByPass come from 240A and ByPass is working. When I turn to Dolby A, there is no sound.

I am working on the 242 B-chain. Will let you know.
The power indicators are ok.

Gordon

Yes, it has been working ok. The problem just happen.
Nothing was changed, it just happen.
ByPass work ok.
Which is the output card ? Cat 242 B-chain ?

What do you think about the Cat. 222 or the two Cat. 350/300 ?
Since the signal come from the output of Cat. 240A to those cards, and Dolby A dont work, but ByPass does, can it be something wrong in eiter 222 or the 350/300 or the Cat 150 ?

Posted by Michael Schaffer (Member # 1204) on 11-18-2005, 07:16 AM:

If you play the Dolby tone loop, you can see the voltage and follow it on the backplane to trace where it is going between cards and where it is lost, and you can also check the voltage at the inputs to the B chain card, and at the main outputs. If you have spare cards to swap, it is easier to do that, of course, but it sounds like you don't. There are signal indicator lights on the preamp, then the level indicators on the NR card(s), and on the matrix card (Cat.No.150) which are explained on the inside of the door and in the manual. It should be fairly easy to see where the signal breaks off. If you have signal at all these points, it is possible, but extremely unlimely that the EQ modules are bad, but it really is extremely unlikely that they all go at the same time. Also, problems like these have been known to get cured by taking all cards out, inspecting and cleaning the connectors, and reseating them firmly. That includes the power supply. I have had CP65s which had bad pins in the connector to the backplane. You can usually see the bad pins and brownish discoloration of the molex connector.

Posted by Magnus Blomberg (Member # 3463) on 11-18-2005, 08:02 AM:

Michael, thanks. Ok, I will do some tests and get back here tomorrow with some results.

Posted by Louis Bornwasser (Member # 3063) on 11-18-2005, 09:04 AM:

The most complicated and failure prone board in that unit is the 150 card. Both L/R and all 4 channels are on that board. It is unlikely that both channels of the NR cards would both fail. If you can swap the 150, do this first. Otherwise, if you have access to a pink noise generator, replace with that in the 150 slot, which will either condemn or else eliminate the entire B chain.

Best to get the CP-65 working first, then look to see what is not right with the DTS interface. Louis

Posted by Phil Fortier (Member # 2827) on 11-19-2005, 01:23 AM:

I had the same thing pull cat150 and clean contacts

Posted by Magnus Blomberg (Member # 3463) on 11-19-2005, 06:14 AM:

Ok, seems that the cleaning of the contacts should be the first thing to do so I will start with that.

Posted by Magnus Blomberg (Member # 3463) on 11-22-2005, 03:37 AM:

Now I have done everything I can to solve the problem. Cleaning the connectors did not help to solve the problem. And the measurements I did indicate that there are something in the Cat. 150. that make trouble. I have now called for a serviceengineer because it goes beoynd my knowledge. But I will be there when he comes, you can be sure about that. Thanks to all of you that tried to help me.

Posted by Gordon McLeod (Member # 33) on 11-22-2005, 09:33 AM:

I would tend to not worry about the NR card the preamp or the 150 since they are optical only portion of the processor
I would tend to lean towards the output section or powersupply since DTS is also affected

Posted by Ken Lackner (Member # 1002) on 11-24-2005, 03:30 PM:

quote: Michael Schaffer
If you play the Dolby tone loop, you can see the voltage and follow it on the backplane to trace where it is going between cards and where it is lost, and you can also check the voltage at the inputs to the B chain card, and at the main outputs.

Sounds like an awesome troubleshooting step. Could you post a list of points to test on the back plane?

Posted by System Notices (Member # 2357) on 05-27-2007, 05:44 AM:

It has been 548 days since the last post.

Posted by Jon Paul Johns (Member # 3443) on 05-27-2007, 05:44 AM:

I have the same problem has this been solved if so, pleas fill me in and what the problem was and how to fix it.

Thanks, Jon

Posted by Steve Guttag (Member # 268) on 05-27-2007, 06:57 AM:

Since the problem for you is both analog AND digital (via the digital input)...your problem is either the Cat 242, Cat 249A (power regulator). The is also the unlikely possibilit of the Cat 250A (power transformer) or bypass relays on the back plane.

I would start with the Cat 249A. When one gets a problem with missing/distorted audio that isn't optical, that is a good place to start. Verify that all three power rails are working properly (don't just use the three red LEDs to verify it...meaure it...however if one or more is out...you need look no further).

Posted by Jon Paul Johns (Member # 3443) on 05-27-2007, 07:22 AM:

Sorry Steve I forgot to mention that I do not use digital I have a DTS-6 installed but drives were bad when I bough it so I have never used it.

Thanks, Jon

Posted by Jon Paul Johns (Member # 3443) on 05-27-2007, 10:59 PM:

Louis do you have any suggestions?

Posted by Magnus Blomberg (Member # 3463) on 05-28-2007, 01:23 AM:

quote:
Sorry Steve I forgot to mention that I do not use digital I have a DTS-6 installed but drives were bad when I bough it so I have never used it. Thanks, Jon

John, the drives are of the same type you find in a pc. Thay are very cheap and you can buy 2 and try with that.

There are two types, cd and dvd. Usually on front of dvd drives, it says "DVD" somewhere. If it does on your DTS-6, then buy 2 dvd-drives at the pc-shop. If not, then you have cd-players and would go for 2 cd-drives.

Posted by Gordon McLeod (Member # 33) on 05-28-2007, 04:16 AM:

Magnus said "John, the drives are of the same type you find in a pc. Thay are very cheap and you can buy 2 and try with that."
That is not true
If you have DVD drives they are usually IDE and as such can be swapped with most generic ones
If they are CD drives then only a few specific brands and models of SCSI drives will work

Posted by Magnus Blomberg (Member # 3463) on 05-28-2007, 05:36 AM:

quote: Gordon McLeod
If you have DVD drives they are usually IDE and as such can be swapped with most generic ones. If they are CD drives then only a few specific brands and models of SCSI drives will work.

John: Correct, my mistake.

So have a look inside the unit and see what brand and model it is. Usually on each player, one will find brand, model no and serial no. Take a note on all this. Then go to the pc-shop and ask for ones with the same specs.

Posted by Jon Paul Johns (Member # 3443) on 05-28-2007, 07:07 AM:

Sorry guys the DTS is the least of my worries the problem is my CP65, pleasr read the topic.

Posted by John Hawkinson (Member # 1135) on 05-28-2007, 11:52 AM:

Jon:

#1 Look at Steve Guttag's suggestions.

#2 You say you have the same problem as the original post, but clearly its different in some way. Always the key to these things is describing them without making assumptions -- starting from someeone else's post is even harder, because there are even more unstated assumptions. So: Please start afresh. Describe your problem again from the beginning, without reference to others problems.

Can you make Dolby level?

--jhawk