This is topic Dolby CP-45 Power Supply in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=003426
Posted by Manny Knowles (Member # 1171) on 05-12-2002, 12:29 AM:
I have a Dolby CP-45 that only works in Bypass mode and the fault is not in the external power transformers (I've changed them).Do I need a new back panel board? Or is there something else to try first?
------------------
~Manny.
Now...where was I ?
Leonard Shelby, MEMENTO.
Posted by Rick Long (Member # 213) on 05-12-2002, 11:02 AM:
Are the power supply status leds lighting up? (plus and minus 12, and plus and minus 6 volts if I recall). If those are not coming on and you are sure the transformers are putting out a.c., might be an idea to start looking for a bridge problem.
There may be a fuse in this thing, but I can't recall ever seeing one.
Posted by Gordon McLeod (Member # 33) on 05-12-2002, 12:58 PM:
Also is the correct transformer being used the backup one for a CP500 looks the same but is a different voltage
Posted by Manny Knowles (Member # 1171) on 05-12-2002, 08:39 PM:
Gord: I checked them by swapping them out with another processor and they worked on that one.But speaking of similar looking power supply units...
Are the Normal/Backup units identical?
------------------
~Manny.
Now...where was I ?
Leonard Shelby, MEMENTO.
Posted by Rick Long (Member # 213) on 05-12-2002, 10:51 PM:
Both the normal and by-pass supplies on a CP-45 are 24 volts, ac.The CP-500 uses 16-volt transformers.
Posted by Stefan Scholz (Member # 147) on 05-14-2002, 02:57 PM:
The power supplies are on the large processor board, switchmode type. I had some of theese fail at a customer's site. You had to replace the whole processor board, but it was a swapout replacement, and a standardized repair fee.
Posted by Manny Knowles (Member # 1171) on 06-04-2002, 12:04 PM:
I have double-checked the following:I have 4 LED's indicating power on the Cat. 511.
There is indeed a fuse on the Cat. 511 and I've changed it - I've seen them work in Bypass mode with a screwy fuse.
The transformers actually have "CP-45" printed on them. I have switched the one from Bypass to the one for Normal and it still only works in Bypass.
Do I need to replace the Cat. 512 board (back panel) or the Cat. 511 (main board)? As a point of interest, the 512 doesn't appear on the Dolby price list.
If I recall correctly, I've swapped out the 511 with one that's known to be working, but I could double-check that next visit.
But that's why I'm looking at the Cat. 512...it's the only thing I haven't changed and it's also where the power supplies get attached.