Film-Tech Forum ARCHIVE: CP-650, How many different power supplies?

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Posted by Mark Gulbrandsen (Member # 72) on 05-09-2010, 06:48 PM:

Am curious how many versions of CP-650 power supplies there have been? I have seen at least three.

Lately I've been seeing a rash of CP-650 power supply failures. Any one else seeing this. The units are only about three years old. This began about three months ago and the first thing that usually goes is the the reliability of the Digital playback. One yesterday left just the right channel playing in analog. A check of several others showed black glop oozing out of a number of the capacitors. Photo attached of the first one that failed. The new supply is much larger and seems beefier but will it last? Or perhaps I should be saying "Will It Blend?"

Bad caps circled in red. Some other cap's tops are bulging outward.

Posted by Mike Blakesley (Member # 26) on 05-09-2010, 09:53 PM:

Uh-oh....isn't our machine 3 years old?

Posted by Martin McCaffery (Member # 37) on 05-09-2010, 10:17 PM:

Hmmm, Mac computers had the same problem with capacitors. I've had 3 power supplies in my G5 iMac, circa 2005. Supposedly there was an international rash of bad capacitors. Wonder if Dolby got caught in the rash.

Posted by Tony Bandiera Jr (Member # 2365) on 05-09-2010, 11:43 PM:

Cap failures of that type are caused by excessive heat, faulty caps (bad electrolyte filling), surge/overvoltage, or (not likely in a supply more than 5 seconds old) reverse polarity.

A bulging top means a cap that is about to fail.

Odds are that you can replace those caps with better quality new ones and revive the supply if no other components got fried.

Posted by Jeremy Weigel (Member # 4208) on 05-10-2010, 12:04 AM:

quote: Martin McCaffery
Supposedly there was an international rash of bad capacitors. Wonder if Dolby got caught in the rash.

Yep. One the major cap suppliers had a faulty QC and sent out several bad batches that ended up mostly on computer motherboards. All major computer makers (Dell, IBM, Gateway, Toshiba, Sony, etc.) were hit hard.

Posted by Marin Zorica (Member # 1716) on 05-10-2010, 02:38 AM:

They use cheapest and bad power supply, normally there is time limit when components will fail, similar to some consumer stuff, even that power supply is same as is in some TV.....

Mark, check power supply on Sony processor [Big Grin]

Posted by Mark Gulbrandsen (Member # 72) on 05-10-2010, 09:15 PM:

Indeed, I agree on the rebuilding of them and at first I thought about doing exactly that but when I got the latest version of the new power supply several months ago for the first time I can say that it was a much beefier unit than the old one was. I ordered two more of the beefier ones today for two critical theaters out of the 5 that are left. I might see about rebuilding the three others since they are less critical. 105 deg.C caps of high quality I would think should last a long time. I admit that this customer is a bit miffed with Dolby at the moment because he was also caught in the middle of the drive debacle and lost I believe a half dozen or so hard drives amongst different sites. So his opinion of Dolby is pretty low at the moment.

quote: Mike Blakesley
Uh-oh....isn't our machine 3 years old?

We will need to check it when I come up in the very near future.

Mark

Posted by Tony Bandiera Jr (Member # 2365) on 05-10-2010, 09:25 PM:

Seems as Dolby, whose products are otherwise pretty good, have a history of bad power supplies/connectors. (CP-100, CP-200, CAT 700 penthouse, DA-20 and now the CP-650.)

So whoever designs the products needs a bit more training on good power supply design/specification. (Hopefully I didn't just insult Sam.)

Posted by Monte L Fullmer (Member # 2797) on 05-11-2010, 12:13 AM:

Yep-time to hit Ra-elco for your replacement caps...

Posted by Louis Bornwasser (Member # 3063) on 05-11-2010, 06:26 AM:

Just another case where "consumer" grade equipment is a mis=fit in professional gear. (CP=500 display screens are another.)

I think those off-the-shelf power supplies should be considered disposable.

Cost cutters got us again. Louis

Posted by Scott Norwood (Member # 30) on 05-11-2010, 07:01 AM:

I don't know the power requirements of the CP650, but it would have been interesting if they had gone with standard ATX computer-type power supplies. Quality ATX power supplies are available (and could be shipped as standard), and a failed one could be replaced with a locally sourced cheapo replacement if necessary to save a show.

Posted by Mark Gulbrandsen (Member # 72) on 05-11-2010, 08:23 AM:

I agree Scott! Something like that would have been too logical though. Dolby always seems to want to be "special" but that "special" just isn't comming through any more... They need to stand back and take a good look at themselves because other companies are flying right past hem with afterburners on and leaving them in the dust. It's kind of sad really... installing Dolby gear actually used to be "special".

Mark

Posted by Robert Minichino (Member # 3495) on 05-11-2010, 08:53 AM:

If Dolby were to use an ATX power supply, they'd need to have additional DC-DC converters for the rails for the analog components. The capacitor troubles of a few years ago stemmed from faulty industrial espionage, and there continues to be trouble from counterfeit parts entering otherwise reputable supply chains.

Wikipedia has a good article on this:

http://en.wikipedia.org/wiki/Capacitor_plague

Posted by Gordon McLeod (Member # 33) on 05-11-2010, 05:24 PM:

Tony the CP100 had probably DOlby's most robust and bullet proof supply never had one fail
As to the CP200 other than the caps drying out and failing which is the norm on most electrolytics eventually they are fairly robust

Posted by Mark Gulbrandsen (Member # 72) on 05-11-2010, 08:25 PM:

Thanks for that link Robert! I agree on the CP-100 Gord. Those were the good ole days when things were REALLY special!

Mark

Posted by Tony Bandiera Jr (Member # 2365) on 05-12-2010, 05:17 PM:

Perhaps I am wrong (wouldn't be the first time) Gordon but I seem to recall a service bulletin on the CP-100 power supply..IIRC the regulator output transistor which was mounted on the chassis had some issues. But I am working on nearly 30 years ago memory... [Big Grin]

The CP-100 was indeed a great processor for it's time...some years ago I had one that was given to me. Other than it's bulk it seemed to perform fairly well.

And wasn't it originally designed and built by DBX for Dolby?

Posted by Louis Bornwasser (Member # 3063) on 05-12-2010, 08:50 PM:

No, it was entirely UK built by a small team. Hand built at home for the first few (25?) units.

Yes, the regulator was an issue, especially since it was hard-mounted.

Noisy little beast, too, especially if the outputs were reduced. I turned then up full, reduced the level at the power amp; a novel idea for me. This fully stopped the hum/noise at the Uptown in DC, back when the SA=5 was installed. (stereo split surrounds off of 6 track mag.) Louis