CP 200 Formats Decoder Cards.

[Mikael Christensen]

Can someone explain the logic behind the Formats cards. I tried to get the "non-sync" input to go through the PL-decoder, without success.
So I bypassed the input transformers, and removed the Cat 108 card. Made my own input (linebuffe) card, now I have Dolby Stereo on format 05.
pl200.jpg
But I would still like to use f.ex. non-sync for surround, do anyone know where to find info. on the Format cards ???

[Dave Macaulay]

It's been many years (1980ish?) but I'm pretty sure I got nonsync through the matrix. The board is crazy complicated but some combination of removing and adding diodes did it. What does your new board do?

[Mikael Christensen]

The board is crazy complicated but some combination of removing and adding diodes did it.

Yes, and that secret i'll like to find out :-)

The "new" card is simply a line-buffer, instead of the optical pre-amp., which would distort with 750mV input level.

[Paul H. Rayton]

I'm not quite sure what your abbreviation (as seen underneath your photo) "f.ex." means, but I'm supposing you mean "effects", correct? What source material are you using? Music only, or soundtrack audio?

I can't cite "chapter & verse" from the CP-200 manual, but the normal configuration of a CP-200 in "non-sync" mode is to play through speaker channels as selected by the small, so-called "suitcase switches" on the back panel. As I recall, there were 2 options, one of which would put the non-sync audio into the surrounds. (There were two such switches, one for music, and one for when using a microphone.) That might solve your dilemma.

[Steve Guttag]

I'm at a considerable distance from my CP200 documents but the key one, if you have a manual (I did a quick check in the F-T warehouse and I didn't see the signal block diagram) is the Block Diagram. That will show you the problem with using the Non-Sync inputs for any form of 2:4 decoding. The audio from that card (CAT143, if I recall correctly) goes all of they over to the second switch card...which is past the CAT150 (2:4) decoder. In order to do a pro-logic decode you'd need to get the signal to come in before the FIRST switch card.

What I, typically, did for getting pro-logic decodes was to use the "MAG-B" input (so it comes in on the CAT201) and then fashion my own wire/connector to where one can select, on the backplane if you have 2-projector or 4 projector (controls how the CAT201 responds...in 2-projector it switches between MAG-A and MAG-B when on projector 2...when in 4-projector, it switches to MAG-B when on projectors 3 or 4. Pulling the suitcase link disables that (all mag would then come in on MAG-A and the Dolby MPU-1 could do its own projector changeover for 2-projector systems). The other end of my wire would be soldered to an available "Future" control line. On the CAT153 cards, I could then program what formats would use that input for pro-logic decode.

The bottom line is though...out of the box, Non-Sync has no audio path to the CAT150 and the suitcase links Paul mentions just determine where the summed audio comes out...Center and/or Surrounds. Left to Left, Right to Right, and Summed to where the suitcase link(s) is set. I may be mistaken, I think you only had the choice of letting the summed audio come out of Center. The other links in that area are for the microphone to choose Center or Surround.

[Mikael Christensen]

Thanks, I know about the Non-Sync "issues", have the signal block diagram but it is in bad quality.
I would still like to know the "logic", behind the format cards. Got this tip from a cinema installer:
On 35mm magnet formatcard, set dip switc to s101-1+2,s102-5,s1031+7,s104-2 and use mag. input B, set to format 38, but it didn't work !

[Paul Finn]

To work with the CP200 you really need the manual! There is a simple way to accomplish what I understand you want to do with 2:4 decode of stereo non-sync audio, and not greatly modify the CP200. A source into the optical stereo audio chain (path) is available on a backplane terminal strip where a SRA-5 adapter would be connected to update the unit for SR decoding. I believe the SRA-5 manual is in the Warehouse on this site. You would connect the non-sync source on the backplane terminals where the SRA-5 output would connect. If you performed the SRA-5 control modifications, Format 05 would enable the new non-sync audio source with 2:4 decoding.

Paul Finn

[Steve Guttag]

The SRA-5 handled the house keeping of completing the signal path for non-SR titles though. So, as I recall (again, I'm not looking at any manuals, at the moment), the control lines for the various formats turn the A or SR NR on as desired and the SRA-5 allowed the preamp out signal to flow through it and then back into the CP200 on Special 1. But, once you change the links on Special 1, you break the signal path (hence, one has to do the overhead of keeping the normal signal path going).

Note, with the optical preamp removed, one could just back feed an external signal into the optical preamp outs, as I recall (pull the CAT108 first)...again, I'd have to check to ensure where those are in the signal path.

[Alan Lyman]

There is a card for each filmsound format. optical-35mag-70mag-nonsync.all the cards are the same,but at the top you set a jumper for wich soundformat its intended for.with the diodes you can set for which sound format in this card,you want what to happen.f.ex. at 04 optical,you would set decoder on-NR on-optical etc. with the dip switches you can make a quick new format,without to solder in diodes.the cards are similar to the one in CP55+65.

[Steve Guttag]

While I don't have the time, at the moment, to go into how to achieve your stated desires, I was mistaken about being able to pull the Optical preamp and "back-feed" the signal path via the Optical Preamp Output. Those terminals are after the CAT109 cards.

[Mark Gulbrandsen]

It's been many years (1980ish?) but I'm pretty sure I got nonsync through the matrix. The board is crazy complicated but some combination of removing and adding diodes did it. What does your new board do?

That is correct Dave. I did exactly the same on at least three CP-200's way back in the 80's and 90's. Either Dolby had a blurb on how to do it, or Sam Chavez gave me the info. But yes, removing a diode and adding two or three sounds correct.

[Steve Guttag]

No, you cannot feed into the Non-Sync terminals and get a pro-logic decode by just changing diodes. In addition to creating the new format, there will be some form of surgery to the backplane will be required. The most popular was to use "MAG-B" inputs. There are other methods but they all involve soldering wires to pads and/or lifting something.