DP70 Replace Shutter Help

[Kyle Mikolajczyk]

Currently one of our 2 DP70s shutter became damaged during use. It appears that the shutter is now bent and should be replaced. We have a spare shutter from a very old DP70 that we use for parts. However, we are not sure what is the best approach of replacing the shutter would be. The question is, is there anyway to replace the shutter without removing the lamp house? (or moving the lamphouse, as the xenon bulb is in them and we do not want to damage the bulbs). Any help would be greatly appreciated.

[David Kornfeld]

Sing Hi-Diddle-Dee-Dee. Okay, which one of you opened the gate when the projector was running? Or disconnected the safety so that the motor could be started with the gate open? Because thats pretty much the only way I can think of to bend the shutter.

Okay, so, in answer to your question: no, you dont have to remove the lamphouse to replace the shutter unless your lamphouse is for some reason right up against the back of the projector. Go to the non-operating side & remove the three screws that hold the covering plate in place on the back of the machine. Voila! There is your shutter. You have to remove the six screws in the pressure ring to release the shutter from the blade mount (and before you do that, you have to remove the guard and block assembly, being careful not to lose the spring). Once youve done all that, put on the new shutter & put it all back together.

Time the shutter before setting the guard or youll have to set it again. And timing those shutters is no quick & easy thing. If youre running -- or intend to run -- 70 on that machine, always time the shutter for 70. Once it's been set for 70, it's good for 35. Be aware that there is NO play; NONE: it's either exactly in time or it isnt. And you have to take into account -- especially if the machine been in use for a long time -- the slop that will have developed in the intermittent idler gear.

Start by ball-parking: set the red line on the intermittent flywheel to the red dot in the casing. (Do this only after making sure the intermittent has been framed so that the white line is in the centre of the positioning circle.) Then place the centre of the shutter as close to the centre of the gate as you can. Youll be off (because of the aforementioned slop), but this will bring you within striking distance. Quasi-tighten four of the six screws, & really tighten just two, because youre in for many long hours of adjustments, & loosening & tightening all six screws gets old fast. Anyway, put in your test film -- RP91, for instance -- & see how far youre off. If youre ghosting on top of the image, you need to move the shutter counter clockwise. If youre ghosting below the image, you need to move the shutter clockwise. (Can you tell Ive done this a few times?) Keep doing this until theres no more ghosting, & it will take no small amount of time: if youre even a millimetre off, youll have ghosting (35 is more forgiving, but the problem there is that if you set it for 35 youll wake up one fine morning & discover it's wildly off for 70). Then tighten the rest of the screws & set the guard & block assembly (remember that the gates on Norelcos should open after the movement) & then reset the threading position indicator, & youre done!

Be aware that if youre gate plate is worn or if anything in the gate itself is out of alignment or adjustment -- and there are a lot of these -- youll get some jitter that appears to be ghosting but isnt. This can drive people not used to doing this procedure insane.

And make sure that no one ever opens the gate while the motor is running or youll have to do this all over again. And take my word for this: if the only thing that happened was a bent shutter, you fellas got off easy: you couldve blown the intermittent idler (an expensive & elusive little part) and/or taken out the shutter drive gear chain. Then you would have a greater appreciation for the word "agony," because pulling that all apart is a nightmare.

Have fun!

[Mark Gulbrandsen]

It's actually very easy to do, but take your time, or better yet get a tech that knows the machine. Also, make sure the shutter is exactly the same as the one coming out as several different openings could be provided by the manufacturer. I have seen at least 3 amongst the 50 odd DP-70 I have rebuilt over the years.

Mark

[Sam Chavez]

I've worked around a few of these at previews way back and noticed folks had added metal to the end of the blade to make the shutter blade wider. Inelegant but effective.

[Kyle Mikolajczyk]

Hello all. Thank you for all the responses, we plan on following David's instructions closely this friday evening. I will keep everyone posted (and show what happened to the shutter!). We believe a screw or something hit the shutter. No idea to be honest but it was not negligence to the best of our knowledge. A tip of the shutter is bent severely, and I believe the part called the wing(?) came off and shredded. Pictures of what I mean to follow friday.

[Kyle Mikolajczyk]

Thanks for all the help with fixing the shutter. After about 5 hours last night we have removed the damaged shutter and replaced it with the spare and it appears to be in fully working order after much adjustment! I have included 2 photos of the damaged shutter, one with a projectionist playing something to celebrate on the DP70! As you can see the issue was that one of the "wings" (I cannot find the name of this part) somehow got damaged to fall off, and the old shutter is missing the wing on the right side. We followed David's instructions to a T with minimal issues! Thanks again.

[Mark Gulbrandsen]

Those are air scoops to aid in moving air over both the shutter and the rear of the gate. One of those falling off like that will certainly cause the shutter to be way out of balance. Was that scoop that fell off completely missing? You sure as heck don't want it floating around in the back end of the machine.

Mark

[Kyle Mikolajczyk]

Those are air scoops to aid in moving air over both the shutter and the rear of the gate. One of those falling off like that will certainly cause the shutter to be way out of balance. Was that scoop that fell off completely missing? You sure as heck don't want it floating around in the back end of the machine.

Mark

When we initially opened it up we did find that was left of it. It basically got shredded and we have since picked up the little bits and vacuumed the inside. Thank you for the advice and the name (air scoops make total sense)

[David Kornfeld]

Happy to have been of some help!
Youre actually not that far from me.....

[Mark Gulbrandsen]

When we initially opened it up we did find that was left of it. It basically got shredded

1. Speaking of shredded... I had a booth monkey at a major Salt Lake City 8 Plex force the trap open while the machine was running. The shutter became all folded up into a little square. And of course the shutter drive and the intermittent fiber gears stripped. I think we were at about 2K in parts by the time I got it running again. I guess I should say that this is one location where Digital conversion probably saved those DP-70!