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This topic comprises 2 pages: 1 2
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Author
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Topic: Hobbyist A-chain in San Diego?
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Jim Henk
Master Film Handler
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Posts: 364
From: San Diego, CA
Registered: Feb 2006
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posted 08-31-2013 10:31 PM
Hi.
I've got a newly installed, never aligned Kelmar ATD-1274-JJ in a restored Century JJ, feeding into a CP-650, and the guy who has been saying he'll come out and bring the scope to get things aligned just isn't going to be able to find the time. Yep. Things happen, all right. Understandable.
So I'm wondering if there's somebody else in the Southern California area who might wanna come out and basically do a service call. This is a machine currently rollable into place in a garage opposite a slide-into-place screen, so nothing fancy. The speakers are even (temporarily) Radio Shack specials, so, as you can guess, I'm just looking to get it working at all. No socks-knocking-off here for the time being. That's in the future.
There are also a couple of lamphouse issues, (Christie H-10) so, optionally, we could talk about that.
I was always on the relief board, (late 70's and early 80's) so I never was able to get anybody to teach me this stuff, and I'm really interested to learn.
Anybody interested? Thanks.
- Jim Henk
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Craig Huegen
Film Handler
Posts: 24
From: Bartelso, IL, US
Registered: May 2013
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posted 09-04-2013 11:30 AM
Yikes. Hopefully someone can help. In the meantime, have you done the good old low-granularity tests, such as the flashlight test (run a small but bright flashlight quickly back and forth across the solar cell to see if you get a rumble out of the processor/speakers), or the white card test (in place, quickly move a card back and forth to interrupt the exciter lamp, where you should hear a rumble / see the signal indicators jump)? If you can't even get that, you may want to give it a once-over before having anyone stop by to look at alignment issues.
As for the H10, mine had a very grimy reflector and dowser lens when I received it. Have you isolated it to the lamphouse vs. the projector? Is your bulb drawing the right current (45-50A)? Is the light a bright white as it hits the back of the projector / shutter, or is it a darker, muddy color? If you remove the projector's lens, do you see the round image from the reflector with the dark spot/silhouette of the bulb & electrodes on the screen (assuming yes since you said you used the alignment tools already).
Sorry if some of this seems basic, just walking through the steps I took from square one as I reassembled and refurbished the equipment I had.
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Scott Norwood
Film God
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Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99
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posted 09-04-2013 12:59 PM
I find the "no sound" problem to be curious. If you power up the CP650 (but leave the amplifiers off!), set the input gain to the midpoint, select format 01, and shine a flashlight (as mentioned above) back and forth across the cell, do you get _no_ signal in the center channel (as measured on the CP650's LCD)?
Is the correct projector input selected? Solar cell cable wired correctly the DB9 end and at the Kelmar reader? Is the power supply for the Kelmar reader good? (The BACP readers have little status LEDs that make troubleshooting something like this much easier.) If the wiring is correct and the reader and processor are both working, you should be able to get at least something out of this system, even if the alignment is completely off.
The A-chain alignment process is described well in the Dolby manual, but it really does require the test films, scope, and RTA to do it properly.
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Jim Henk
Master Film Handler
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Posts: 364
From: San Diego, CA
Registered: Feb 2006
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posted 09-05-2013 12:35 AM
Think what I'll do over the weekend is:
a) sound pickup - try the flashlight on the pickup, go back over the wiring a fourth time, and try the digital pickup to see what happens, like Louis suggested.
b) lamphouse - Lens change makes no difference. And it's not the projector. Again, timing is fine, and there are no obstructions. The Align-O-Tron showed the alignment of the lens shaft to aperture plate is spot on. I'm thinking of banging my head forcefully against the garage door for a while. No... no... although I have plenty of Asprin, it still doesn't accomplish much... Punt. Closer... One thing at a time. Back to step a). There *are* worse things in life.
BTW Craig, yep, no nice round light on the screen with no lens at all. It's either the lamphouse, or the pedestal somehow, but then, alignment tests should have shown that.
But it's really hot and humid here (for us...) so I'd have to open my garage door for air at night, and that's not a very smart thing to do in this neighborhood. (I'm looking to move in the late Fall / early Winter) So the weekend it is.
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Leo Enticknap
Film God
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Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 09-05-2013 11:18 AM
quote: Jim Henk b) lamphouse - Lens change makes no difference. And it's not the projector. Again, timing is fine, and there are no obstructions. The Align-O-Tron showed the alignment of the lens shaft to aperture plate is spot on.
I'm not familiar with that model of lamphouse, but the reflector is the only thing left I can think of ... except for one off-the-wall long shot. I once had a lamphouse problem (lamps were blackening and failing after only 500 hours or so), which after much wailing and gnashing of teeth turned out to be a failed ammeter on the rectifier: it was showing a much lower current than was actually being delivered. If you've got the reverse going on (say, it's showing 60 amps when it's actually only delivering 35), that could explain the dim picture.
quote: Jim Henk But it's really hot and humid here (for us...) so I'd have to open my garage door for air at night, and that's not a very smart thing to do in this neighborhood.
We visited the San Diego Zoo on Sunday and my shirt was drenched after only about an hour of walking around! If it's any consolation, the Inland Empire is even hotter: overnight low of 91 in the back yard in Loma Linda last night. It's a lot less humid, though.
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