Film-Tech Forum ARCHIVE: Need help remote troubleshooting CP-50 problem

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Posted by Lyle Romer (Member # 1266) on 09-19-2010, 01:13 PM:

One of our locations is reporting the following in an auditorium with a CP-50. They say that the left and right channels both appear to cut in and out running in optical. Running in bypass they say sounds fine (or as good as bypass sounds). They say when it happens the left channel will have very soft sound with the booth monitor switched to processor but neither left or right have anything if the booth monitor is switched to amps.

Any ideas on what I can tell them to look at?

Posted by Tony Bandiera Jr (Member # 2365) on 09-19-2010, 01:21 PM:

Ok, I am gonna try to help someone again, let's hope it works out better than the last three times..

Lyle, some questions:

What brand booth monitor? The Com. Eng. MS 100 has been known to cause similar problems on occasion.

What type/brand of optical reader?

Did this problem crop up suddenly?

Do the meters on the meter card in the processor quit showing signal when the problem happens?

Something to try: with the processor and amps turned off, pull each card out and re-seat it. See if the problem goes away.

It is remotely possible that the left/right amplifier is going bad, but let's rule out the front end first.

Let me know what you find and we'll go from there.

Posted by Lyle Romer (Member # 1266) on 09-19-2010, 03:16 PM:

The monitor is "Component engineering 3417" according to the email they sent.

To check the meters I'll have to tell them to run out of bypass and watch the meters while the problem happens.

Also the auditorium is biamped so L and R channels are on separate amps completely.

Posted by Gordon McLeod (Member # 33) on 09-19-2010, 04:12 PM:

What version of the cat 150 do they have

Posted by Tony Bandiera Jr (Member # 2365) on 09-19-2010, 04:48 PM:

Thank you Lyle.

The monitor is most likely a MS-55 or MS-100, the number they sent you is a serial number.

I'll rule out the amps for now since it is very unlikely for BOTH of them to go bad at the same time.

Gordon, good point on the CAT 150...wasn't there someone here with a similar problem that turned out to be the CAT 150?

Lyle, if they have another CP-50 (or a CP-65 or CP-200) on site they can try exchanging CAT 150 cards to see if the problem moves with the card..if so then the CAT 150 is bad. If not then the problem is elsewhere in the CP-50.

I'm not 100% sure, but I think the meters on the meter card will respond even in bypass..

Times like this make me wish I had my old CP-50 handy to test my theories. [Smile]

Posted by Steve Guttag (Member # 268) on 09-19-2010, 05:09 PM:

Tony, you ignorant slut:

The Component Engineering 3417 is the "THX" monitor

The Cat 150 is a good place to start. The power rails are another good place to measure...make sure they are all there...don't be too worried if the +/- 15V rails are closer to +/- 10.5 V...if they are less then you have power supply problems too.

At this age, the Non-Sync/Optical switch (presuming a Cat 112) can be causing issue with its mechanical contacts though it is odd that both left/right have the same problem at the same time.

Steve

Posted by Tony Bandiera Jr (Member # 2365) on 09-19-2010, 05:17 PM:

Steve-o:

Although it has been decades since I was an ignorant slut, let the record show that I am still a slut. [Big Grin]

(Anyone know what movie/tv show I lifted that from?)

BTW, isn't slut German for total stud? [Smile]

Thank you for the interesting correction..you are right of course. I hadn't encountered but a few THX monitors in my service days which is why that number flew by my radar.

But this also brings up another possible area..maybe the problem is in the monitor's crossover cards or power supply.

Posted by Lyle Romer (Member # 1266) on 09-19-2010, 05:27 PM:

CAT150E

I'll have them look at the meters and see what is happening while in bypass.

There is a CP200 in the building also so I'll have them swap the CAT150 and see if the problem follows the card.

Thanks for all the suggestions.

Posted by Steve Guttag (Member # 268) on 09-19-2010, 09:35 PM:

I REAL common problem of the Cat 150E is the power regulators not making good contact with their sockets...make sure they are pushed in good.

Since it is an E...do the LEDs on the card track with what you are hearing?

Steve

Posted by Sam D. Chavez (Member # 1841) on 09-19-2010, 10:40 PM:

Tony you I.S.!

Saturday Night Live of course. Jane Curtin, and Dan Ackroyd playing Shana Alexander and James Kilpatrick are the people being spoofed.

Posted by Tony Bandiera Jr (Member # 2365) on 09-20-2010, 01:22 PM:

You got it Sam!! I loved that show and that routine in particular.