Film-Tech Forum ARCHIVE: Dolby Cat. 700 power supply

This is topic Dolby Cat. 700 power supply in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tim Johnson (Member # 1403) on 12-02-2007, 01:02 PM:

Hi,
I recently had a Dolby Cat. 700 power supply go out on me. It keeps blowing the fuse in the power supply after about 20 min. I contacted my supplier to get a new one and he was told by Dolby they longer make the power supply. I was wondering if anyone new were I could get a replacement or have the one I have fixed? Also is there a way to make your own power supply to replace the Dolby one? Is Dolby not making these anymore because they are concentrating more toward the Digital side and starting to get away from 35mm?

Posted by Mark Gulbrandsen (Member # 72) on 12-02-2007, 01:10 PM:

Unless some area of the board have turned to charcoal these can usually be repaired. The repair of switching supplies is no secret and is pretty easy in fact! Also just to be sure its NOT the board check the Molex connectors as they sometimes burn up and become toasty looking and fail. If this is the case just eliminate the Molex's and solder the wires directly to the PCB. You'll have 100% reliability this way.

Our company also converts the CAT 700 to red LED at a far more reasonable price than will Dolby.

Mark

Posted by Tim Johnson (Member # 1403) on 12-02-2007, 01:21 PM:

I'm pretty sure it is not the cable but I will check it the next time I am there. As far as the conversion to LED, would this require a different power supply and approx. what would the cost of this conversion be? Thanks

Posted by Mark Gulbrandsen (Member # 72) on 12-02-2007, 05:12 PM:

Check all the white Molex connectors very carefully!! I tink it runs about $650.00 for the conversion. We use a different power supply and we custom machine a new mount so you can utilize the standard Dolby CAT 701/2 LED head.

Mark

Posted by Tim Reed (Member # 137) on 12-02-2007, 06:25 PM:

quote: Mark Gulbrandsen
I tink it runs about $650.00 for the conversion.

Posted by Steve Guttag (Member # 268) on 12-02-2007, 07:54 PM:

OMG...why would anyone convert a Cat 700 to red LED? The lamp is cheaper, user changable and will track better than the LED based system. If you are truely desparate for the power supply, get a separate supply and just wire it up. I think the EPT lamp runs on 10.8V or so...there are many supplies that can power this thing.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 12-02-2007, 08:12 PM:

quote: Steve Guttag
OMG...why would anyone convert a Cat 700 to red LED?

If you have a cracked light pipe as I have had (twice)its the only option.. ok... or the garbage can... since Dolby has no light pipes. We were quoted $1200.00 by Dolby for them to do the conversion so I think our price is more than fair.

Posted by Sam D. Chavez (Member # 1841) on 12-02-2007, 08:31 PM:

I bought a couple of these power supplies, last batch from Dolby. Nothing special but easy to install.

Posted by Monte L Fullmer (Member # 2797) on 12-02-2007, 11:07 PM:

quote: Steve Guttag
I think the EPT lamp runs on 10.8V or so...there are many supplies that can power this thing.

We have a wad of old Kelmar exciter bulb PS units that has the possibility to be the replacement PS for these units since they do put out a good amount of adjustable DC voltage and amperage run to power those bulbs.

Yet, this is also on my mind since I do take care of a 6plex that has 4-CAT700 units as well...and I've had to replace PS units in two of them...

[ 12-03-2007, 02:24 AM: Message edited by: Monte L Fullmer ]

Posted by Louis Bornwasser (Member # 3063) on 12-04-2007, 05:06 AM:

How do light pipes go bad? Louis

Posted by Mark Gulbrandsen (Member # 72) on 12-04-2007, 08:20 AM:

quote: Louis Bornwasser
How do light pipes go bad? Louis

I had two failures... One was scratched(more like a tiny chip out of the end) on the end that sits behind the film... another pipe's glass rod was cracked internally. Both resulted in extremely uneven light across the scanned area and very high error rates, the internally cracked one wouldn't even exhibit a usable video waveform... it was grossly distorted. We sent the one with the scratched surface to an optical guy at Hill AFB and he tried to polish the surface... he had some luck with it and it was better after the polishing but still not gooed enough to produce low tracking rates.... Both got converted to LED... I used the small C.E. supply to power the LED on both of them. Both also use the standard Dolby LED head.

Mark