CP750 problems thread

[Philip Jones]

We had our first one die last month - all working fine and then half way through a show there was a loud pop, no sound and a completely dead 750. It had been in service since late-2010.

Lost the show but got the spare installed ready for the next one.

We have a similarly old one running in another screen so I've got another spare all loaded up with the IP address and config so it should be just plug and play if\when that one dies.

[Pete Naples]

We do offer a CP750 refurbishment service, we have a colleague setup with SMT rework capability so all the failure-prone components get replaced, as well as the PSU and it's cabling. We also add a small fan, and give it some general TLC.

[Marcel Birgelen]

You don't have to give exact prices, but you can do this for around the same price a "spare unit from Ebay" would cost me?

[Pete Naples]

You don't have to give exact prices, but you can do this for around the same price a "spare unit from Ebay" would cost me?

Probably not.
There are professionally refurbished, upgraded and warrantied.

[Steve Guttag]

We are looking into doing a similar service. I'd suspect that the cost would be a little MORE than the motherboard used to cost. There is a fair amount of labor involved as there are a LOT of parts (capacitors) and possibly SMD line amps and/or opamps. Furthermore, some are out of production (especially post C19 and AKM's factory burndown).

Getting used is likely getting you something that already has experienced "trauma."

I would recommend going with an external supply on any units still in service. It does two things...it removes a heat source from within the cabinet and it should get the power rails back in spec. It won't reverse any damage thus far but it might slow/stop further damage.

[Mark Gulbrandsen]

I think most of the issues here can be tracked back to the power supplies, especially switching type power supplies. I had literally 30 some CP-650's power supplies fail at right around three years old. On those they all only needed to be recapped, and I did them right in the booths. Electrolytic capacitors are literally the most often failed parts in power supplies and other devices. Sometimes they swell up, sometimes they look ok, but will check bad. I have also had the same issue with DTS motherboards. The early A-Open XD-10 Motherboards especially, all eventually failed. DTS would only rebuild them and to install the new MB they also required a new chassis and about $1200 of your bucks. So 1200 bucks for an $80 new motherboard and a .25 cent chassis piece. I did these right in the booths too. They were some of the easiest repairs I ever did...

[Colm Nolan]

Hard to get a hold of internal PSU never mind the external ones. I've seen everything from the loud pop, to the siren type blaring to the display faded or the unit locking up on one button at the front all meanwhile the CP650's and older continue to work away

[Steve Guttag]

We have been able to source the original internal supply...they were made in USA (in Pennsylvania). As for external supplies, Mean Well makes a suitable one that just needs its DIN plug removed and a 4-pin female XLR installed. I'd have to scroll back but I thought I had posted the model of the Mean Well supply.

[Ryan Gallagher]

Is it possible to get a DM to the CP750 setup software. I don't have a dolby customer login.

Mine does not boot every time, but when it does it gets to the state the input and mute buttons work. I tried the flashlight trick to see if I could detect anything being drawn to the LCD without a backlight, but nothing visible. I assume LCD brightness is a variable within the setup software.

I got my part number matched PSU from Radwell.

[Mark Gulbrandsen]

I'm having JSD80s fail, at this point. Not in a massive way but the cards are starting to go and without a repair source (nor do I know what on them are failing). We sacrificed a couple of removed units for parts to keep existing units going but have exhausted those cards now. So, I would not favor a JSD80, at this point. JSD60s can definitely get flaky on their outputs but the JSD100, thus far, has had a near perfect record for me.

On the CP750 repair...whereas the problems seem to stem from power supply and capacitor, I'd think, all-in, a repair could be in the ⅓ of new price range. If so, then the reliability is bound to be high and the cost savings significant. Exhibitors (multiple) have expressed a desire to hold their own (not improve) if it can save significant money. These past two years have been notably lean years. Naturally, we do offer current-model replacement systems. I would argue that there is no reason to believe that current offerings will be more reliable than the CP750, however. Typically, older technology has a higher degree of stability given that it is less complicated.

The advantage to repairing existing supplies is that it can happen fast, while the Tech is in town. He can even do an entire booth full of processors as I have done a number of times. None of this is a bad reflection on Dolby, or any other processor manufacturer, it's just that capacitors have a fairly finite life running in switching supplies. The theater owner can decide if he wants brand new or existing supplies repaired. Rebuilding a supply takes about an hour after you have done a few. Does Dolby even sell CP-750 parts any longer? I doubt it. That will answer most theater owners questions. At that point it is also... do I repair, or replace the units.

The other interesting supply is the potted one in the DTS players. It takes +5 volts and converts it to +/- 15 volts for the analog section. A number of companies including Meanwell, make compatible supplies that work, but all new versions have to be wired in and secured to the PCB.

[Steve Guttag]

Another reason I favor the external supply approach is...the tech need not do the work. Dolby has it set up on a 4-pin XLR. Just plug it in...done...all fixed.