Film-Tech Forum ARCHIVE: CP 650 Won't boot

This is topic CP 650 Won't boot in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Martin McCaffery (Member # 37) on 03-30-2018, 05:08 PM:

Probably a dead power supply, just looking for confirmation.
Getting power, but no fan, no boot-up, just the power on/override light in bright red.
Is there something I can do to confirm or jump start?
Are 650 power supplies still available?

Posted by Mark Gulbrandsen (Member # 72) on 03-30-2018, 06:32 PM:

MOst likely that. Pull the supply out and look for leaking crud out of the capacitors. I've replaced a few CP-650 power supplies over the years but recapped way way more...

Mark

Posted by Marcel Birgelen (Member # 6801) on 03-30-2018, 06:54 PM:

Dolby won't sell you the Cat. 776 as it's EOL, but they regularly appear on Ebay.

As an alternative, I've seen CP 650s go for $500~$1000, it never hurts to have a cold spare at those prices.

Posted by Martin McCaffery (Member # 37) on 03-30-2018, 06:55 PM:

Meant to add that we do get sound via bypass from the 35mm.
Is there any test to confirm power supply failure?

Posted by Leo Enticknap (Member # 534) on 03-30-2018, 07:35 PM:

Measure the DC voltage coming out of it?

As Mark points out, capacitor plague is a likely cause, and easily visible. If that's the problem, the capacitors could be replaced, if you have a good soldering iron and a steady hand.

Posted by Sam D. Chavez (Member # 1841) on 03-30-2018, 08:30 PM:

The Voltage on the 5 Volt rail should be above 4.75 on the +5VB terminal on the inner front plane. Any lower and it's likely not to start and stay in bypass. It could also be the memory board located on the Cat. 774, a very pricey board.

BACP bought the remaining CP650's and related finished assemblies. We ship parts every week all over the USA but can also ship internationally. Used can also be good but no telling what you get. There are three completely different supplies. We only stock the last version.

Posted by Adrian Avram (Member # 7931) on 03-31-2018, 12:22 AM:

100 % PS failure. Just fixed two of them yesterday. You can pull it out and look at the output capacitors. Sometime they look fine, other time you can clearly see they are bulged and leaky.
However, the main reason the PS won't start are two small caps buried near the daughter board. They are both 100 uF/35V.
Replacing those will bring the PS on, no matter in what state are the output caps.
Adi

Posted by Sam D. Chavez (Member # 1841) on 03-31-2018, 10:43 AM:

Adrian. do you recall which version of the power supply you repaired? There is the initial black Lambda, Integrated power and one other brand that is not coming to mind at the moment.

Thanks.

Posted by Martin McCaffery (Member # 37) on 03-31-2018, 01:26 PM:

Thanks for the suggestions.
I've pulled the power supply. No sign of ruptured or swollen caps (checked with a magnifying glass). Have a used PS coming from the company doing our hearing assistance install.
So, we're down at least until Tuesday.
The frustratingly ironic part is we were closed all of March to put in new seats. Friday was supposed to be our grand reopening. TV cameras were here for the failure! I had booted up on Wednesday and everything was fine.
Since we can't talk about religion I won't make a Good Friday/Easter joke [Wink]

Local News Coverage

Posted by Adrian Avram (Member # 7931) on 03-31-2018, 01:29 PM:

Hi,
Yes, the model I fixed so far is AM-120U-T133-171 from Power Solution Inc.
I know some CP650's are also equipped with a different PS (can't recall the model now). I have not seen any faults on them either (some have 10+ years of run).

Posted by Sam D. Chavez (Member # 1841) on 03-31-2018, 04:12 PM:

The Power Solutions was the last version in the 650. Integrated Power was second and Llamda was the first. They all failed more than they should.

Posted by Frank Cox (Member # 6258) on 03-31-2018, 05:29 PM:

That sure sucks the joy out of the grand re-opening.

A friend of mine lost his rectifier for the first night of Jurassic Park, back in the day....

Posted by Ioannis Syrogiannis (Member # 3235) on 04-01-2018, 09:36 AM:

Equipment have a tendency to make their failures apparent after periods of staying idle.
Power supply units dwell on that habit.

Having the premiere gone bad the only day of year that cinemas (and entertainment societies) were accustomed to be closed, though, is a memorable twist. Even knowing that when failures happen, they happen so in each and every day.

Posted by Martin Brooks (Member # 1269) on 04-03-2018, 02:51 PM:

There are several on eBay right now, the lowest priced of which are $750 and $770, but of course, it's always a risk buying on eBay, although both sellers have 100% feedback rating.

Posted by Martin McCaffery (Member # 37) on 04-03-2018, 02:58 PM:

Ok, got a used supply. It is actually older than the one I took out.
Checked the caps and they looked ok.
The first time I turned it on, the display panel lit up, the fan worked, and the format button defaulted to U2. But no boot up.
Turned off all of the power and tried again. Booted up fine. Ran some trailers and a bit of feature and it sounded fine. Shut everything down.
Went back up a few hours later and the same thing happened. Had to be started twice.
Are these the symptoms of a PS going bad, or do I have another bug in the machine.
Leaving it powered on for now.

Posted by Sam D. Chavez (Member # 1841) on 04-03-2018, 07:58 PM:

Check the 5 Volt supply. I'll send you a new one to try if it will help. You've suffered enough. PM me your info.

Posted by Pete Naples (Member # 761) on 04-04-2018, 08:48 AM:

Sam to the rescue, again!

Yup that sounds like the PSU on the vinegar strokes to me. Leaving it powered up until replaced is wise.

I never considered PSUs as Dolby's strong point, but I've a couple of CP55s still in service, on their original PSU. Best part of 30 years, yet some of these CP650s and CP750s....

I'd one site, 3 screens all new CP750.

100% PSU failure within 6 weeks of opening.

Posted by Steve Guttag (Member # 268) on 04-04-2018, 09:00 AM:

Prior to the CP500, Dolby made or substantially made their power supplies. The CP55 regulator (CAT249) could cook. The CP65 (CAT249A) did very well. The CP200 PS1(B) while didn't outright fail too much (an odd bridge rectifier here or there) would loosen up on its filter caps and get ripple. Then again, the CP200 (and the CP50) really had mediocre power (lots of ripple).

While the CP500 and beyond used "purchased" power supplies, they have not proven to be the most reliable either. DA20s, CAT700s, CP650s, CP750s all have been bit by failing power supplies. The CP750 supply was apparently a defective run (part change that didn't perform as well as the original). Never had a DMA8 Plus fail and it uses the same supply.

Posted by Martin McCaffery (Member # 37) on 04-04-2018, 01:13 PM:

Got through last night's show, been in touch with Sam and have the unit running permanently on.

Gotta give if props for running 15+ years. It's held up a whole lot better than our Solaria One.

Posted by Carsten Kurz (Member # 5396) on 04-04-2018, 03:51 PM:

Our CP65 powers up and down daily since more than 20 years now. Switching power supplies in later devices seem to be mostly OEM parts, and while one should assume them being made by companies specializing in power supply design and thus being more reliable, it looks as if this isn't the case. The CP750 supply seems(ed) to fail mostly on a very cheap simple protection device that is easy to replace. I think the AP20 supplies also have a tendency to fail, but it seems they suffer from bad ventilation and long or 24/7 operation due to some overheating in densly populated racks. Knock-on-wood, ours is running for 5 years now, but only for a couple of hours each day (and cut from power during off-times). Looks as if USL did a better job on their PSUs.

- Carsten

Posted by Martin McCaffery (Member # 37) on 04-04-2018, 06:23 PM:

Of course, when I got here in 1985 they were still using an amp that had tubes in it from 1941. I don't know when those tubes were actually put in the amp, but that's some serious longevity.

Posted by Mark Gulbrandsen (Member # 72) on 04-04-2018, 06:29 PM:

Power supply failures are a Dolby tradition. I think the ONLY processor that did not experience this was the CP-100 and to a lesser degree the CP-200... but eventually the latter also failed after many years. I have had supplies fail in every single cinema product they have made over the years. I can remember when the DA-20 forst came out and Dolby Techs of that era came around and switched out all the power supplies and the DC interconnect cables for no charge.

quote: Carsten Kurz
Looks as if USL did a better job on their PSUs.

Indeed! The USL also loks to be an OEM supply, but out of 334 units I put in not one single failure of any processors. Perhaps they'll start dropping like fiies in a few more years... Switching supplies just all eventually seem to do that. I repair a lot of test equipment and those pieces that use switchers seem to experisnce the same thing. Might be tme to go back to analog supplies.

Mark

Posted by Stephan Shelley (Member # 8587) on 04-04-2018, 07:43 PM:

I know of a couple of JSD-80s supplies that have failed and plenty of JS-200s.

Posted by Sam D. Chavez (Member # 1841) on 04-04-2018, 07:56 PM:

JS 200 supplies definitely fail plenty. I took over service for QSC on older USL units and was cleaned out of a big box of supplies in two months tops.

Posted by Mark Gulbrandsen (Member # 72) on 04-04-2018, 11:02 PM:

The only thing I ever had fail in one was the external power supply switch. I think everyone of those failed. I always took those out and bypassed them.

I was referring to the latest stuff they produce. I don;t have any JS still in service. They all were replaced by JSD-100's and a few JSD-60's.

Mark