You take the good, you take the bad......

[Jon Dent]

Good: New IMS3000 servers. Work great. UI has quirks that irritate a bit, but whatever.

Great: Finally got a dedicated DCA1622 amp for our sub. Sub now sounds cleaner than ever, and would be capable of running at proper level vs the other channels, but all that power is making shit behind the screen rattle so I had to turn it back down a bit

Bad: To bring us back down to Earth, one of our CP750s failed (ironically the one on the screen with the new amp). I'm guessing it's the infamous power supply issue since the whole unit is completely dead. So now on a weekend with two big movies (Addams 2 and Venom 2) we're down to a single screen.

The gods of theatrical exhibition are a fickle bunch...

[Leo Enticknap]

If it's completely dead, then yes, most likely the power supply (especially if the unit was manufactured in late 2014 or earlier). If it's the equally infamous "level drop disease," then it's the motherboard. The sorta good news is that a power supply card costs in the low three figures, but a motherboard is in the low four.

I'm pretty sure that we have a power supply card in stock and could overnight it if your regular supplier can't. Feel free to call 714 751-7998 if we can help. Swapping them out is very easy: the only gotcha is that if the Molex-type connector for the output power has overheated, it may have gotten brittle, in which case it'll be very easy to break the locking tab.

Shit rattling behind the screen is usually fixable without too much trouble. The bigger problem can be a new or reinvigorated sub making the screen itself vibrate, especially if its an older one tensioned with springs (not sisal rope) that have lost some of their pull over the years.

[Jon Dent]

Its a newer screen, but it is sprint tensioned so you might be in the ballpark. Nice thing was the sub itself sounded just fine (no distortion or chuffing). Now granted the rattles appeared during a custom policy trailer I mixed that has VERY heavy LFE levels against relatively quiet main channels (at least at first) to try to maximize impact on our old setup, and it may just be a bit too hot now that the sub is running much closer to proper calibration.

As far as the power supply our regular guy is sending a replacement plus a CP750 loaner in case that doesn't fix the issue. I do appreciate the offer though.

And it did not suffer any level drops that I could detect. The RTA didn't work well at all with a Behringer ECM8000 but I hear that's not unusual or a sign of issues.

[Steve Guttag]

We always sold the external CP750 power supply (1 per complex) since they install in seconds. The external supply is identical to the internal one. The only difference is that it is in a plastic case (with the various cords/connectors). We, also, typically, have both internal and external supplies in stock.

I'd say that the only PITA on the internal supply are the lower screws (putting them back in).

[Leo Enticknap]

Yes - they're nonmagnetic, so my trick is to secure them to the end of a screwdriver using a thin (as in, about 1/3" wide) strip of painter's tape, stuck firmly onto the screwdriver shaft, but lightly around the head of the screw itself. After positioning and turning the screw about two revolutions, you should be able to pull the screwdriver away and the tape with it, leaving the screw started in the thread. Remove the tape, then tighten the screw.

In most of the failed power supply cards I've swapped out, the output connector has shown signs of heat damage, and I've accidentally snapped the locking tab off when squeezing it more times than not. It doesn't really matter, because the connector seats tightly enough that the tab isn't essential. But it still annoys me when I fail to finish a job with the equipment in anything less than the condition I found it.

I did once get a quote for an external power supply unit after an 11-plex I service had two of the internal cards bite the dust within a month, for exactly the reason you suggested (end user can swap the external one in quickly and easily). However, it was around three times the price of one of the internal cards, and the customer decided against it.

The RTA didn't work well at all with a Behringer ECM8000 but I hear that's not unusual or a sign of issues.

You're never going to get a very good result tuning a room with just a single microphone, though it will usually be an improvement on leaving the EQ flat. The CP750 ships with the gain pot all the way down, so you will need to increase it; and the ECM8000 needs Phantom power (can be enabled in the CP750 app). I carry a mic (Dayton Audio EMM-6) and a 100ft XLR cable with me for use directly with the built-in software RTA in a 750, 850, or 950, to make rough improvements if I can hear something very wrong at a site, and a bad amp or speaker driver is ruled out. It's feasible to haul that around in my traveling toolkit: five mics, stands, Octacapture and cables is two flight cases, and so is not realistic for carrying around on spec.

[Steve Guttag]

Leo, we source the CP750 power supplies (both) directly and put the NL4F on the external cable...so the costs are not as dramatic. Still, the cost of the external supply is less than one lost show. It isn't going to go bad on the shelf either.

[Carsten Kurz]

There was a bad batch on these power supplies. Dolby has a technote describing the most typical failure. It is very easy to fix. You may want to buy a new supply, but try to repair the bad one and keep it on the shelf. Email me if you want the power supply tech doc.

[Steve Guttag]

Are you talking about VR2 and its mating fuse?

[Jon Dent]

Turns out the CP750 main board ended up fried as well. Replacing the power supply did give it a few blinking status lights but the front display is dead and it doesn't really produce any sound. Of course our installer wants up to upgrade to a CP950 but that's not the most appealing option given how much we just dropped on new servers.