Film-Tech Forum ARCHIVE: CP-65 problem

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Posted by Bradley Johnson (Member # 5154) on 04-15-2009, 09:40 PM:

I am having a issue with a cat 150 card in a CP-65.
It is popping and cracking through the speakers whenever there is a slight vibration in the rack or the unit itself. If you move the card ever so slightly in the socket it will make this sound. It is also visible on the output leds on the cat 150 card. It seems like dirty contacts on the card itself or the socket but I have cleaned them quite well with no change.....Any thoughts?????

thanks!

Posted by Marin Zorica (Member # 1716) on 04-16-2009, 04:55 AM:

If that is case, than probably some bad soldering on card....try to resolder some pads on it, or inspect it under light maybe you get see what pad has bad soldering.

Posted by Louis Bornwasser (Member # 3063) on 04-16-2009, 11:47 AM:

Look carefully at the silver can (chrystal). Many times all you need is to solder it back down. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 04-16-2009, 01:57 PM:

Depending on the generation of the card (150B, D, E, F) you may also have either a loose IC in a socket or a bad connection in one of the piggyback leads.

You can also try moving the delay rotary switch (note the setting first and put it back) to both ends of its range a few times..I had a 150B that was noisy because of it.

Posted by Steve Guttag (Member # 268) on 04-16-2009, 08:24 PM:

Or my personal favorite that is unique to the Cat 150E (about half of the CP65s...the other half should be 150Fs)...the power regulators are socketed but the leads are not long enough and they are tin plated sockets.

Press the regulator leads all of the way down into the sockets so they take a straighter path rather than bending a 90-degree path.

Also, the mother board on the CP65 could be affecting things...make sure its solder pads are good...particularly on the Cat 150 socket.

I'd start with the regulators first.

Steve

Posted by Bradley Johnson (Member # 5154) on 04-18-2009, 12:06 PM:

Well, as it turns out, there is a more serious problem than just static. The 150 (and yes it is a E) is not passing signal at all. No sound when in Dolby A or SR, non sync passes to L-R with no issues as long as the jumper for non sync on the logic card is not set for 2:4. Mono operation also works fine. I checked and re-soldered the 150 socket on the mo-board just in case, no fix there. Yes I have to agree with you Steve on the power reg situation, that big heat sink is the only thing that has enough mass to bounce around when I tap the card, I did take the sink and regs off and cleaned the legs, but I am going to try putting them in strait all the way in the socket as you suggested. I have a new cat 150F card coming on Monday, sure hope that fixes the problem.

Posted by Steve Guttag (Member # 268) on 04-18-2009, 12:21 PM:

Bradley,

Note, I did not say to remove the regulators from the heat sink...just have the leads go at the sockets more directly than at a right-angle bend.

I've also had Dolby's "flameproof" resistors fail (open). If possible, measure the voltage regulators to see what their outputs are (tack wires to their outputs so you can measure them once the card is inserted.

Odds are, your problem is centered around the regulators with my first bet on the sockets/connections to them.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 04-18-2009, 01:09 PM:

quote: Steve Guttag
Odds are, your problem is centered around the regulators with my first bet on the sockets/connections to them.

Amazingly... I agree with Steve! Sockets of all sorts have been the plague with Dolby over the years... from these simple and very definately not needed regulator sockets to power supply sockets on DA-20's, CAT 700's and so on that fail. You simply do not need most of the sockets they put on equipment!! They are only there for those that don't know how to solder wires in place or keep the wires they try to solder in order. Eliminating those sockets would have eliminated 80% of Dolby's woes over the years. I eliminated MOST of the sockets on Dolby gear that I serviced over the years and never had to go back to fix anythng. On the regulators... properly unsolder the sockets from the PCB and solder the new regulators directly to the PCB!!! There's perhaps 3 bucks total in parts there to make the board function again...

P.S. You won't find any of these sorts of sockets for regulators on later Dolby manufactured PCB's... it's surface mount today although very similar regulators are still commonly used... the metal tab is now soldered directly to a large copper foil on the board. That foil acts as the heat sink for the regulator.

Mark

Posted by Bradley Johnson (Member # 5154) on 04-18-2009, 04:03 PM:

I am doing a swap for a new (or newer) card from Dolby, it will be here on Monday. Dolby was very helpful in getting it to us asap. If they (Dolby) had not had such a fast turnaround, then I would have soldered the regs directly to the board as suggested. Seems like kind of a bad idea to have sockets, particularly on the voltage regulators, but maybe they wanted to be able to replace all the regs and heat sink as one unit when faulty????? I dont want to mod this board as I am sending it back to Dolby, but if it happens again,,,I am going in deep with hot iron. [Mad]

Posted by Steve Guttag (Member # 268) on 04-18-2009, 04:59 PM:

I don't think you'll have enough lead length to omit the sockets and keep the heat sink. By skipping the 90-degree bend, you'll at least sink the leads further into the sockets.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 04-18-2009, 08:30 PM:

Yea.... extend the regulator leads a bit and it does work... I've done it a number of times.

Mark

Posted by Bradley Johnson (Member # 5154) on 04-19-2009, 11:18 PM:

Well, I have a new (or newer) card arriving tomorrow from Dolby. The problem is very strange, the old card passes no audio at all. I sure hope the problem is the card and not the Mo-board. I will post tomorrow with the results of the new 150.

Posted by Sam D. Chavez (Member # 1841) on 04-20-2009, 01:12 AM:

You said in an earlier comment that mono worked fine. Mono film sound goes through the 150 card like all analog film sound. Did you mean bypass?

If mono sound is going through the 150, the center signal presence light should light.

If the new card works, all is well, if no change, then you need to dig deep.

Posted by Bradley Johnson (Member # 5154) on 04-20-2009, 01:09 PM:

quote: Sam D. Chavez
You said in an earlier comment that mono worked fine. Mono film sound goes through the 150 card like all analog film sound. Did you mean bypass?

Here is the best description I can make,,,and it is strange (at least to me),

If I use Dolby SR or Dolby A with a film, there is no sound at all from either projector. There are no signal lights anywhere.
In non-sync, if I have the logic card set to 2:4,,there is no sound at all. IF I have non-sync set for standard, I get sound in the L-R and see signal lights on the outputs..... When playing a film, if I set the processor to anything but mono, no sound at all. Mono works fine, which is how we have been running since Friday night. I have not used bypass at all. When doing the A-chain alignment, I got good Dolby tone to the Cat 222 card on both projectors, and could hear tone from the center channel. However, if any other format was selected,,,,no sound. I have tested all the amps and speakers, they are all good(but I knew that already). The 150 card will still make static and popping sounds if you touch it, no matter the format. (you can also see this on the leds on the cat 150 and the outputs. No other card will make this sound when touched, poked or beaten. Also, I have poked at the rear mo-board with the unit removed from the rack(with a non conductive instrument) to see if there is something amiss there. I cannot reproduce the popping or static noise by doing this. Incidentally, the unit will behave this way with nothing hooked up to it at all. (all outputs to amps removed and projector inputs removed) You cant hear it of course, but you can still see the leds jumping around when the Cat 150 is touched. If I owned a Catt 85c I could properly test the CP without the 150 card installed,,,,,might have to buy one...........

Posted by Scott Norwood (Member # 30) on 04-20-2009, 01:41 PM:

Check the cat. 443 (format card). Does it look like someone has added or removed diodes from it? It could be that your unit was set up for some custom formats.

If you need to borrow a cat. 85, let me know. If you want to pay shipping, I'll loan you mine for a couple of weeks. I don't believe that Dolby still sells it, but Component Engineering makes a replacement which is better in pretty much every way.

Posted by Sam D. Chavez (Member # 1841) on 04-20-2009, 02:09 PM:

Does the Cat. 150 center channel signal presence light when you are running Mono?

Posted by Bradley Johnson (Member # 5154) on 04-20-2009, 08:09 PM:

oh boy, the new card came today, put it in, and everything is working fine now. Thank God..... Keeping my fingers crossed for tonight's show. (Witch MT) had 5 people last night. I cant begin to describe how happy I am that the card was the actual problem, and not something on the Mo-board.......I can say this much,,,,,a full L-C-R-S system is a much harder beast to tame than,,,,,well,,,,Mono.....

My next question is based on getting dolby level on the CP....In the CP manual it says to do this with the processor set for MONO. I set Dolby tone in this setting only to find that when Switched to SR the 222 card is slammed in the red almost all the time. Sounds,,,,not so good. I went back and set Dolby level in SR mode and now it sounds as it should.........Am I missing something here?

quote: Scott Norwood
If you need to borrow a cat. 85, let me know. If you want to pay shipping, I'll loan you mine for a couple of weeks. I don't believe that Dolby still sells it, but Component Engineering makes a replacement which is better in pretty much every way.

Scott,,,,thank you so much for that offer, that is very generous and helpful. I now understand what a useful tool the cat 85 is. Particularly when starting completely from scratch with used gear. I think I am going to have to pony up and get the CE one,,,,,,,but ouch, they sure dont give them away, [Eek!]

Posted by Steve Guttag (Member # 268) on 04-20-2009, 08:23 PM:

Bradley...go back and reset Dolby Level in MONO and nothing but on ANY Dolby processor.

You are setting the level to the INPUT of the NR card(s). Once you turn the NR on, you have several things at play...one, the tracking of the NR cards themselves but in the case of SR in a movie theatre, there is also a 3dB boost applied to offset the 3dB reduction in recording level. Thus, you will see that the LEDs read higher in SR than other formats.

Why the 3dB change? Well since SR offered so much more noise reduction than A...it was decided that they could record 3dB quieter and then boost it back in the processor. This increased the output level by that 3dB and thus SR can play louder than A and yet have a lower background noise.

Steve

Posted by Bradley Johnson (Member # 5154) on 04-21-2009, 11:50 AM:

I know this most likely doesn't make a difference, but, the CP-65 in question is not fitted with cat 300s or 350s. It has a Cat 222 card with Dolby A/SR. When the 222 card goes into really hard red, it actually sounds very obviously compressed, nasty sounding compression. Best way I can describe it is the sound that a cheap audio compressor makes when driven hard with a fast release time. You can hear it pumping. After setting the Dolby tone via SR, it sounds fine. There is no compression or gain reduction devises in the system and there is a ton of headroom on the B-chain side, so I am not sure why this is happening. On a up note, last nights show went great. There is still a lot of tweaking required but, I am not sure if the patrons that have been coming to this theater can handle any more dynamic range after listing to a single cabinet on a 25 watt amp for 30 some odd years. I made some DB measurements on the old system and it had a range of about 74dba to 80dba tops. Last night, the new set up ran from 67dba to 88dba. Quite a difference, it sounded like a movie.........I will go back and reset the Dolby tone via mono and post the results.

thanks all,

Posted by Sam D. Chavez (Member # 1841) on 04-21-2009, 01:44 PM:

FYI, the Dolby level measurement at the output terminals of the Cat. No. 240 preamplifier card should be around .300 Volts AC, regardless of the format chosen. This is only important to rule out overloading the input to the 222 SR/A card.

Also, don't be fooled by how the lights on the 222 card work. Two green lights mean Dolby Cal. The red lights that comes on when you go over Dolby level do not indicate clipping, just that you are over Dolby level by any amount. Kind of silly I know, bet them's the facts.

Posted by Tony Bandiera Jr (Member # 2365) on 04-21-2009, 02:42 PM:

quote: Bradley Johnson
It has a Cat 222 card with Dolby A/SR.

The 222SR/A card has a poor implementation of SR, so I am not surprised it sounds that way.

The CP-65 at UC Irvine has it and I can hear it pumping as well...one of these days I'm gonna throw a pair of CAT300's in it to see if it sounds better.

BTW, I have CAT300's for sale in the Equipment Forum...if you want a pair for your processor contact me via the info there and I'll set you up with a deal.

Posted by Steve Guttag (Member # 268) on 04-21-2009, 05:37 PM:

Note...part of the magic of the Dolby NR process is that it only really has an effect on lower level signals. Above Dolby Level, it should not be companding anymore. The idea being, when the signal is strong, the noise is already sufficiently below the signal and no altering of the singal is needed...unlike other NR designs. It is one of the reasons that Dolby-Level is so critical to the process.

Steve

Posted by Scott Norwood (Member # 30) on 04-21-2009, 05:42 PM:

Get Tony's cat. 300s if you can possibly afford them. The difference is significant. You can keep the 222 SR/A for Dolby A decoding, or replace it with a regular cat. 222.

Posted by Sam D. Chavez (Member # 1841) on 04-21-2009, 11:37 PM:

350's will work as well for this purpose. 300's are A/SR, 350's are SR only if memory serves.

Posted by Bradley Johnson (Member # 5154) on 04-22-2009, 12:38 AM:

I think I am going to see what Tony will take to part with his Cat 300s. If the Cat 222 SR/A sounds like this in normal SR operation, then it is complete jive.

Posted by Sam D. Chavez (Member # 1841) on 04-22-2009, 09:03 AM:

Not to unsell Tony's Cat. 300's, but it should not sound that bad using normal 222's. You may have another problem, maybe with the 222, it's not unknowm.

Posted by Steve Guttag (Member # 268) on 04-22-2009, 11:26 AM:

I agree it should not have a particularly distorted sound on the Cat 222 but I have found the Cat 222 sound to be objectionable as have customers who pointed it out to me. I've done the side-by-side test in a CP65 and the difference when done that way was pretty clear.

You ARE using Dolby Tone...right...not pink noise to set levels.

Sam is quite correct too that the Cat 350s are SR only and the Cat 300s are SR and A. the CP65 will be smart enough to know when either the Cat 300s or 350s are inserted to use them for SR in preference over the Cat 222SR/A. If you do get the Cat 300s, you will have 4-channels of A-type NR in there for all of your big 70mm features [Wink]

Steve

Posted by Louis Bornwasser (Member # 3063) on 04-22-2009, 01:05 PM:

I agree with Sam; the 222sr/a is not that bad especially with exciter lamps or Jax lites. It becomes somewhat worse with a really good LED reader, especially if you are flat up to 16K.

It is not important unless you have a small room, really good hf speakers and bi amping. Big room, average speakers, you won't know or care. Louis

Posted by Tony Bandiera Jr (Member # 2365) on 04-22-2009, 01:48 PM:

Louis I respectfully disagree with what you said..it doesn't matter what size of room or if you're bi-amped or not, the 222SR/A is audibly inferior. You can hear a difference on a lot of films. Older prints especially, the NR effect is not as solid.

It's not necessarily a BAD card, but it just doesn't measure up against a 300/350. Dolby had to cut a lot of complexity to cram TWO Channels of SR-like NR onto that single tiny card.

And Sam is right, problems with the 222 are not unheard of, Bradley may have issues with it as well.

Posted by John Hawkinson (Member # 1135) on 04-22-2009, 03:36 PM:

Bradley: What test material are you using to judge the quality of your CP65 (and Cat. 222)? Are you listening on monitors or in the room itself?

Also, how many turns did you have to adjust from calibrating in SR to calibrating in mono?

--jhawk

Posted by Bradley Johnson (Member # 5154) on 04-23-2009, 12:25 AM:

quote: Steve Guttag
You ARE using Dolby Tone...right...not pink noise to set levels.

Yes I am using Dolby tone to set the Dolby level.

quote: Louis Bornwasser
I agree with Sam; the 222sr/a is not that bad especially with exciter lamps or Jax lites. It becomes somewhat worse with a really good LED reader, especially if you are flat up to 16K.

We have upgraded from mono Jax lites to the RSTR-2000 readers, but I have to tell you that this is not some audiophile bat ear type difference, it is night and day. When I set everything up with good Dolby tone on the mono setting and then played a trailer, it was completely unacceptable. It actually sounds very good at the moment (set Dolby level on SR setting instead of mono)but I am not ruling out the possibility of a bad 222 card, especially after having the bad 150 card right out of the gate. I did buy the CP-65 off ebay, it could have been filled with someones bad leftovers???? [Frown]

We are at least up an running at this time and the owner is over the top happy with the results, but I want this thing to run "by the book" so I will be getting to the bottom of this issue. I am trying to get a CE pink generator off ebay, and that will eliminate quite a few questions and get the system in the ballpark. Then I can actually make some more educated deductions,,,,,unless, of course, one of you guys out bids me,,,,,then I will have to borrow Scott's! [Smile]

Posted by Sam D. Chavez (Member # 1841) on 04-23-2009, 01:19 AM:

The Cat. No. 85 only checks the B-chain, but it won't do anything to deduce the condition of the 222 card.

It does sound more and more like a bad 222 card.

I've got some used Cat. 350's you can borrow as well as an old style Cat. 85 if you need them for process of elimination.

Do check Voltage level at the output of the preamp as I mentioned before. If it's way off after you've set Dolby level it's further indication of trouble in the 222.

Posted by Bradley Johnson (Member # 5154) on 04-23-2009, 01:32 AM:

The cinema is closed on Thursdays so I will have all day tomorrow to test. I will check the pre-amp voltage. I do understand that the 85 will only help me with the B-chain side of things and not with diagnosing the cat 222, but I need to properly set my outputs and EQ. I think only then I can make an educated diagnosis on the 222. I have been doing everything with a KT DN-6000 RTA and a hand held DB meter. Without having the C85, it is possible that my gain structure is totally sideways. [Eek!]

Posted by Tony Bandiera Jr (Member # 2365) on 04-25-2009, 12:19 AM:

quote: Bradley Johnson
I did buy the CP-65 off ebay, it could have been filled with someones bad leftovers???? [Frown]

Rhuh, ro Rastro. I have a sneaky suspicion I know who you got it from...he's well known for passing off junk. Post the seller's eBay name here if you dare, or send it to me in a PM and I can confirm...