Film-Tech Forum ARCHIVE: Supply Voltages for Cat. 150.

This is topic Supply Voltages for Cat. 150. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Stephen Furley (Member # 1277) on 06-13-2007, 03:13 PM:

I won the Dolby SA4 on Ebay recently, and it has just arrived; I collected it from the Parcelforce depot at lunchtime today.

The two supply terminals on the back of the case are labeled +24V and -15V. However, the supply rails on the Cat. 150 card itself are labeled +24V and +15V. Should the 15V supply be positive or negative?

Posted by Christos Mitsakis (Member # 143) on 06-14-2007, 02:26 AM:

Stephen,
Pins 16 and T are for +24V
Pins 3 and C are for the +15V rail
Pins 13 and P are for the -15V rail
pin 9 is ground.
I hope this helps.

Christos

Posted by Stephen Furley (Member # 1277) on 06-14-2007, 03:40 AM:

Christos, thank you. That's odd, because there's only one 15V terminal, the negative one, on the SA4. Maybe the older cards didn't use +15V?

Looks like I may have to run an extra wire to the card connector in the unit.

Posted by William Phillips (Member # 1162) on 06-14-2007, 01:18 PM:

Maybe the +15V supply is regulated down from the +24V supply. Most standard +15V regulators say the 7815 series can easily handle +30V or so.
Plus it also cuts out the need for seperate positive supplys. Its pretty much common practice in linear PSUs to have the higher voltage and then drop it down to the lower ones( unless its really high ). Saves on heavy transformers and parts.

Posted by Louis Bornwasser (Member # 3063) on 06-14-2007, 02:57 PM:

Looking at the SA-3 connections (page 7.22 of the CP-100 manual)(in manuals section) only +24 and -15 are connected. Of course, this is for the old cat 116a, not the 150 card. I believe they are plug compatible so I would try it without the +12 and see if all works well. Louis

Posted by Stephen Furley (Member # 1277) on 06-14-2007, 04:40 PM:

Thank you gentlemen, you were right. Louis, if you move on a few pages, to page 7.34, in the CP-100 manual it actually has the SA4 connections diagram. I'd looked in the manuals section for a SA4 manual, but there were only those for the SA5 and SA10. It hadn't occurred to me that in might be bound within the CP-100 manual, along with those for the SA2 and SA3.

Posted by Bill Gabel (Member # 1105) on 06-14-2007, 05:51 PM:

Your SA4 came from a CP-100 install originally.

Posted by Stephen Furley (Member # 1277) on 06-14-2007, 06:08 PM:

Yes, I know it was designed to be used with a CP-100, but I didn't realise that the documentation for it was included in the CP-100 manual. It's rather like the MPU-1; which can be used with a CP-200 processor for example, but it has its own manual; it's not included in the CP-200 one.