Barco DP2K-20C light pipe temp high

[Andrew Thomas]

Hello, I recently installed a pair of 20Cs, and I'm getting perfect temps on everything except the light pipe on one unit. It's going north of 100C and shutting the lamp off typically in around 15 minutes from cold boot and strike. Any suggestions for things to do to resolve this issue?

[Steve Guttag]

In a 20C? 95% of the time that is poor coolant flow, if any. The light pipe takes the brunt of the heat and if the coolant doesn't take it away, it will over-temp. That is where I would start my quest. Open the reservoir and see, with the pump running (either in test mode or with the lamp on) if

1. There is sufficient coolant
2. It is sufficiently rolling in the reservoir (if need be, compare to one of the ones not giving you grief).
3. Also ensure that lamp alignment is good. The light pipe will heat up more with a misaligned lamp blasting the light all over the cooling plate rather than putting it through the light pipe.
4. Make sure all of the filters are clean and with good air flow. By clean I mean when you hold them up to light, they should look almost invisible.

[Dave Macaulay]

I've only seen this when the light engine has clogged up with little or no coolant flow. Confirm that the DMD and TEC temps are normal, and TEC voltages reasonable - I rarely see them working hard at the full 12V. Low flow doesn't seem to super affect these temps but the TEC voltage goes up.

In refill mode or with lamp on, the coolant reservoir should be quite active. Compare the two projectors: if the hot one isn't showing as much flow as the cool one you may have a blockage.

It is possible to dissolve whatever clogs the LE by pumping cleaning vinegar and/or CLR though it. Not by filling the cooling system! You need an external small pump, I have a few salvaged from Christie film gate cooling tanks and have used one of them. It did unclog a 99% blocked DP2000 light engine that kept shutting down with your error. Rinse thoroughly afterward!

I had one 20C where the cold mirror had broken free and tilted a bit, the light beam tried to burn a hole through the cooling plate. Obviously it couldn't with the thing water cooled but it did leave a singed circle beside the light pipe entrance.

[Leo Enticknap]

Agreed - flush the bugger out.

A low tech way, but one that I've found works, is to take the 100ml syringe that Barco sells you to flush the Series 1 pressurized circuits (or just buy a 100ml syringe from any drugstore for a few bucks), and use that to flush the light engine section of a Series 2 circuit. Fill the syringe with distilled water, attach a short length of hose with a Series 2 male quick release coupling to the end of it, attach a length of hose with a female coupling to the other end of the light engine section, draining into a bucket, pump the water through, rinse (literally!) and repeat. You should find that there is less resistance in the plunger with every syringe full of water that you push through. Finally, when you're confident that any crystallized coolant has been flushed out, fill the syringe with fresh coolant and push it into the light engine.

Needless to say, it would be a good idea to put fresh coolant into the reservoir and the rest of the circuit, too.

[Mark Gulbrandsen]

I find it odd that we're this far into S2 equipment and Barco STILL has cooling system problems. I had one cooling system problem where a pump failed... and zero problems with NEC cooling systems. And with B parts prices as high as they are from Barco, there no doubt has to be some really pissed off customers.

[Steve Guttag]

And yet...we have more, overall failures on consumables on NEC...fans that will eat you alive (NEC really hiked up the prices the last time). We really don't have Barco cooling problems, as a rule. If one changes the pump at the prescribed intervals. Conversely, we put in an NEC this past year...54 fans on one projector...54 of anything...even if low cost is expensive! Even the smaller projectors have something like 20+ fans. It is a far cry from the 10 or so of the NC1200/2000 days. They all have their ups and downs. But seriously, I don't as a rule have Barco coolant problems. We do change the coolant, which probably goes a long way to not having the problems. You'll be happy to know that the SPxK series projectors have something like a 50,000-hour life on their coolant/cooling system. They still have WAY fewer fans than NEC and are WAY more serviceable. NEC almost makes it harder as they go and more convoluted.

[Mark Gulbrandsen]

You seem to be the only one that claims to have problems with them... I have had six issues out of 334 projectors over 11 years, which is pretty darn good and far better than GDC's record. where I have had about 20 problems.... In fact in Europe, NEC are considered the most reliable projectors. We had a bunch of 2500S's in Salt Lake City that were Dolby leased system's, and those too gave no trouble.

[Leo Enticknap]

Broadly agreed that the Achilles' heel of Barco projectors is the liquid cooling system, and of NEC projectors are the multiple fans that require periodic replacement. Also agreed that if these are replaced (coolant and pump, in the case of Barco) at the recommended intervals, the risk of failure in service is near zero. The one exception to that is Series 1 Barcos, in which UV damage to the coolant hoses will eventually cause problems if they're not replaced, even though their replacement is not recommended as part of the planned maintenance schedule at all.

To be fair, the Barco cooling systems improved through generations of projector. The Series 1 pressurized system is a pain in the poohole to service, requiring you to faff about with syringes and bicycle pumps, and carrying the high risk that you'll end up spraying coolant all over the booth. That pressure also creates a high risk of leaks. The unpressurized Series 2 iteration uses better hose and is much easier to service, but it still needs an annual coolant flush and replace, and a new pump every four. And as Steve points out, the SP2K/SP4K has a self contained pump/reservoir/plumbing module that is entirely sealed and which you just swap out wholesale if anything goes wrong with it. I'm sure that a new one won't be cheap for a projector out of warranty, though, and if they really are good for 50,000 hours, I suspect that most projectors will have expired warranties by the time replacement is needed.

[Pete Naples]

I'd have thought you'd have been seeing higher block/DMD temperatures too, if the liquid cooling was compromised. Certainly when I've seen a blocked LE or a failed pump, it's usually DMD that goes first.

I recently was called to a 12C which suddenly reported exactly what you're describing, light pipe climbing over 100C and the machine shutting the lamp off. This machine was also struggling for light.

I had a long hard look at the mirrors and thoroughly cleaned them, they weren't especially dirty TBH, nothing remarkable.

Next I checked the light pipe for cracks, chips etc. All good there. Followed by the usual fun of re-aligning it. (this projector is hard to access and you cannot see the screen from the box LE side of the machine)

A coffee, a bit of thinking and head-scratching, following a line of thought like Steve's point#3 above. Has it got the right lamp, has it got the right lamp adaptor, is the lamp alignment peaked? YES.

I wondered about the fold mirror. So set about the alignment procedure.
I'm glad I did, becuase after another 20 minutes of tinkering, two things changed.

1. The light increased massively, easily 100% on this one.

2. The Light Pipe is now running at a much more comfortable temperature.

It's set me wondering, how/why did the fold mirror get out of alignment? The locknuts were tight enough. I can only thing that expansion/contraction cycles have caused it to drift. The box the projector lives in is not really adequately cooled.

[Steve Guttag]

The cold mirror can be part of the issue on a 12C where it is all air cooled. Another thing to look at is cover plate around the light pipe. It should be chromed but if it has lost its shine, it will collect heat more than reflect it...which will make that thermal sensor rise.

If one is running a 12C with a 2KW (or 2.2KW...yes you can run those too if you need more than 9500 lumens), the cold mirror and that reflective coating are critical as they are some of the only means of cooling beyond the fans themselves (including the exhaust fan).

And Mark, I didn't say that the NEC wasn't reliable. I was comparing NEC to Barco consumables (coolant and cooling pump versus massive fan changes). NEC's upkeep isn't so cheap once you get into fan replacement time. On the early models (1200/2000), there were not so many fans and it wasn't so bad. But 54 fans is ridiculous. The cost of the fans and technician time to change them all exceeds the cost of coolant and pump at their prescribed intervals.

Leo, even with a projector warranty, I doubt that the SP4K cooling system swaps would be in warranty as they are a consumable, and would be part of the projector's upkeep. I think a bigger hidden charge for LP projectors (anybody's) is that LP system, that typically is only rated for 20,000-30,000 hours. And it is a consumable, just like a xenon lamp.

[Mark Gulbrandsen]

And Mark, I didn't say that the NEC wasn't reliable. I was comparing NEC to Barco consumables (coolant and cooling pump versus massive fan changes). NEC's upkeep isn't so cheap once you get into fan replacement time. On the early models (1200/2000), there were not so many fans and it wasn't so bad. But 54 fans is ridiculous. The cost of the fans and technician time to change them all exceeds the cost of coolant and pump at their prescribed intervals.

.

What fan failures? I have had zero. I changed out the Power On, card cage, and ICP fans out of caution after about 5 years. And to be fair I know another Tech in the Northwest that has changed out one exhaust blower fan. Perhaps your customers leave the filters out...

[Steve Guttag]

Nope, they don't leave the filters out (I've had ICP fan failures too). NEC's perscribed fan replacement interval is 20,000 hours. You have posted that you change them all. Okay...fair enough. And, on the NC1200/2000 we are not talking about a huge number though the current cost of the fans is getting near the cooling pump price but you'll change those fans out a couple of times before the cooling pump...if you go at NEC's recommended times. On our NEC systems, we power all of the way down to shut off the AC-On fan too so it does not prematurely age.

[Leo Enticknap]

Leo, even with a projector warranty, I doubt that the SP4K cooling system swaps would be in warranty as they are a consumable, and would be part of the projector's upkeep.

I'd be a bit surprised if they refused, if the unit in question has actually failed. They'd likely refuse to replace it if it had done 50,000 hours and still worked, and you asked for a new one as a preventative maintenance measure. But if it had died, I'd be surprised if they wanted to know how many hours it had done, and refused to give you a new one it if it had run beyond the recommended replacement interval. But with Barco and NEC both jacking up the cost of warranties and one-time parts purchases, anything is possible, I guess. Cinionic have given me a new pump for a projector under warranty once, for a projector that I'm pretty sure had not had a new one in over four years (but which the end user had kept in warranty). Whether they looked for that information in the diagnostics zip I sent them before issuing the replacement, I have no idea.

[Steve Guttag]

Oh...I thought you meant after the 50K. Yes, if they prematurely failed, then yes, I'd expect them to warrant it. Have you looked at the logs on the web analyzer. MANY things have a running timer on them as well as board swaps (original serial number versus current one). I don't see the cooling assembly showing run time hours but it does show fan speeds and projector run hours.

[Andrew Thomas]

Had a tech dispatched by MIT. They think the line is clogged somewhere in the light engine as the pump pushes fluid just fine from it's output side if you bypass it going into the rest of the cooling system. They wanted to tear the cooling system apart to try and determine exactly where the clog is (tech was thinking maybe in one of the heatsinks). Any suggestions before going that route?