Film-Tech Forum ARCHIVE: DP100 DMD overheating

This is topic DP100 DMD overheating in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Brian DeCiancio (Member # 1422) on 04-28-2016, 10:13 AM:

I have a DP100 running 6500 watts that the DMD temps reach, and sometimes exceed, the max temp of 140 degrees. All other temps are normal.

All 3 DMDs run high, separated by only a few degrees.

We have changed the pump, heat exchanger and flow switch. Filters and all internal air vents are clean and all fans are verified working.

The coolant change was done "by the book" and the system pressurized. We even went as far as separating each component and forcing coolant back and forth to dislodge any possible clog. There was a bit of crud, but not large chunks of anything.

No excessive force was needed to push the fluid thru, and the pump had a strong flow.

Has anyone ever tried any type of detergent or cooling system flush product on a projector?

Would there be any reason to think it would harm any components?

Barco was unable to help in any way.

Posted by Gordon McLeod (Member # 33) on 04-28-2016, 01:26 PM:

We were forced to use hig pressure air to clear the coolant from fittings and we did it by applying the air so it was opposite to the direction of the coolant flow to dislodge any aluminum oxide that may be restricting the flow

Posted by Marco Giustini (Member # 4544) on 04-28-2016, 01:27 PM:

You seem to have covered all the bases. It's usually lack of flow. But if you have flow and you can easily syringe coolant manually in the circuit,then I'm not sure.

Can you run the circuit so coolant goes back into the bottle, do you see coolant flowing?

When you turn the lamp on do the dmds get to 140 degrees very quickly or slowly?

Posted by Brian DeCiancio (Member # 1422) on 04-28-2016, 02:45 PM:

Yes, we watched it flow freely into the bottle.

It takes about 5-10 minutes for the DMDs to get to 120, then a slow, but steady increase over 30+ minutes to reach max.

BTW, I have a spare light engine (with a bad DMD) that I am willing to dig into and part out if it helps my cause and someone has some insight.

Once the lamp is turned off, it cools down very quickly.

Posted by Stephan Shelley (Member # 8587) on 04-28-2016, 03:47 PM:

Have to ask if the radiator fan is running. Also not sure if that Barco has it but the series 2 use the peltier cooling system as well. Is the voltage there for it?

Posted by Timothy Eiler (Member # 383) on 04-28-2016, 03:55 PM:

Does the temp in the booth stay consistent?

Posted by Brian DeCiancio (Member # 1422) on 04-28-2016, 04:43 PM:

There are 4 fans in front of the heat exchanger (radiator). Yes, they are all running.

The DP100 is nearly identical to the DP3000. Reading the service manual indicates that it does indeed use the Peltier modules if that part is also the same. I saw no reference to voltage in Communicator for them however.

The booth temp is not relevant to this issue as all other temp readings are fine and the ambient temp is normal, but yes, it is consistent.

Posted by Stephan Shelley (Member # 8587) on 04-28-2016, 05:15 PM:

There should be a led on the fan controller board labeled VTEC. It should be lit when the lamp is on. This indicates voltage to the peltier cooler.

Posted by Sam D. Chavez (Member # 1841) on 04-28-2016, 08:30 PM:

Good call Stephan! This would explain a lot.

Posted by Marco Giustini (Member # 4544) on 04-29-2016, 10:48 AM:

I guess an error should pop in if the VTEC is not there.

If you see coolant flowing, I'd be surprised if deposits inside the circuit could cause such a loss of efficiency. I feel those circuits are very overspec'd, I once used a DP90 with no coolant flow and the peltier were enough to keep it cool - but with a smaller lamp.

When the DMD's reach 100°C or so, what's the temperature of the coolant?

Posted by Steve Kraus (Member # 476) on 04-29-2016, 12:29 PM:

That doesn't mean the reverse (coolant but no Peltier) is true. Maybe that's the most important of all.

Posted by Marco Giustini (Member # 4544) on 04-29-2016, 05:09 PM:

Sure. I cannot remember the DP100 but as I said I would think that a missing voltage would be reported by the software. Definitely worth checking it, Peltier are before the coolant block so I wouldn't be surprised if they acted as insulator if they are not working.

TEC is shown under STATUS/VOLTAGES. Alternatively, take a look at the SMPS control board - first on top. On the left hand side there are three LED's, one for each DMD, showing when the peltiers are on. I'm sure you are aware that if you open the card cage you will need to authorise the projector again, you will need a password and potentially a dallas key.

Also, those old machines tend to develop unreliable contacts inside, sometimes just opening the card cage may cause trouble! [Smile]

Posted by Brian DeCiancio (Member # 1422) on 04-29-2016, 09:38 PM:

Still working on the issue, but I appreciate all the input and thoughts.

Posted by Gavin Lewarne (Member # 5397) on 05-01-2016, 05:57 AM:

just curious how the VTEC applies to the series 2 12c

My VTEC indicator is never on, and after 2 hours my DMDs sit at 39c

my fan controller board was replaced for another reason recently, but it never lit on the old one either. I just figured that was/is normal

Posted by Marco Giustini (Member # 4544) on 05-01-2016, 11:46 AM:

I do know 12C does not have coolant, but I cannot really remember re. peltiers. I guess the 12C it's only cooled by air. The ID card will tell the software what projector that is and what to expect in terms of connected sensors and fans.

Posted by Dave Macaulay (Member # 813) on 05-01-2016, 02:33 PM:

There is Peltier cooling on the 12C, but as you found it rarely gets used. I'm not sure how much heat is dissipated in the DMDs or if it changes with light/dark positioning. Even on a 32B I haven't seen full cooler voltage (12V) on a DMD.

Posted by Marco Giustini (Member # 4544) on 05-01-2016, 03:17 PM:

When projecting black the light is being dissipated on a heatsink which is located on the light engine itself. That's why when testing a Barco it is recommended to leave it on black for a while and then check the temperatures.

On a Christie it goes on a heatsink fixed on the front of the projector - it's massive because it acts as a heatsink itself!

I would have thought that the TEC LED would get solid straight away when the lamp is turned on. I cannot remember seeing a Barco turning the TEC LED on and off depending on the temperature, but I'll check next time.