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Topic: Basement LED Kelmar readers

Kevin Crawford
Expert Film Handler

Posts: 207
From: Sacramento, CA, USA
Registered: May 2000

posted 07-07-2000 01:49 PM

Dave,

For the analog, Component put resisters in the reader. The resisters cut the gain from them. Do not ask me why they did this. I have yet heard a good reason why. You should take the analog reader out and cut the resisters. There are two. They are just two metal jumpers on the circut board. I believe they are J5 and J6.

As for the Dolby basement readers. They seem to come in batches of good and bad. I have had to replace some that were brand new and others not at all. They mostly run between 3 and 5. There is one that I have seen that runs at .5 and 1. That was on Titantic after 5 months. That was impressive. Most of the readers I have replaced were due to operator neglegence. For some reason these people believe that oil needs to coat the outside of the machine as well as inside.

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John Wilson
Film God

Posts: 5438
From: Sydney, Australia.
Registered: Dec 1999

posted 07-08-2000 02:25 AM

.5 and 1? That's pretty impressive. We're running a couple of trailers now that were at 7. and 8 right out of the box. (But that's trailers, not a feature.)

Our print of Gladiator (Italian from memory) had a 6 error rate from day one, again brand new but the dolby digital track was marked on every reel.

Yes, cut the resisters on the analogue. Our digital leds are fading and will need replacing soon (Just over two years old).

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 07-08-2000 07:09 AM

I think Dolby had a service bulletin out regarding the resistors on the reader assemblies, and Strong put one out as well last year some time. That service bulletin would be on our website (www.strong-cinema.com) -- sorry I don't remember which one it is but you can find it easy. Cutting those two jumpers increases the gain from the analog reader. Basically you get all you can from the reader and processor preamps, and that allows you to lower operating current of the LED's big time.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 07-08-2000 11:39 AM

Yes Joe that sticker says it all, the reader met the same quality standards as the rest of the christie projector

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Dave Cutler
Master Film Handler

Posts: 277
From: Centennial, CO
Registered: Jun 2000

posted 07-09-2000 12:47 PM

Brad, (or anyone)

How should the power supply be set when installing new LED's on a CE?

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 07-09-2000 02:13 PM

Dave;
Take a look at the service bulletins on the Strong website (www.strong-cinema.com); the procedure is outlined there. Dolby's and CE's site might have the info as well. Basically, you just about max out gain from the processors preamp and then use LED power to get to Dolby level.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 07-09-2000 02:59 PM

The problem with maxed out gain is that you are also amplifing noise.
CE has a method of setting the current using a amp meter

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 07-09-2000 03:17 PM

I'd be interested in CE's method for setting the level. As I stated earlier, I get so much light from a Kelmar, it's power supply must be all the way down as well as the preamp gains when the led is brand new. That's fantastic! (Of course, this requires the led be aligned absolutely precisely...but that's the whole point.)

Otherwise, I generally set the preamp gains about 1/2 up. The trimpots are 18 turns, so turn them up until they start clicking and back off about 9 turns. Then roughly set Dolby level with the led's power supply and then tweek it with the preamp gains. I'd be interested in other people's recommendations (always looking for a better way to do things ), but that's how I've been doing it with excellent results.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-09-2000 10:01 PM

I have never had any trouble with Kelmar basement readers except for one defective LED that had several segments out. There is no reason that they should not be able to be aligned to work as good as the competitors. One thing for sure....the LED bracket is a whole lot beefier and solid than CE's is. I do prefer the Cat 701's to anything else out there but all basement readers in general should work fine IF THE PROJECTOR IS OPERATING PROPERLY!!!
Mark

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John Wilson
Film God

Posts: 5438
From: Sydney, Australia.
Registered: Dec 1999

posted 07-10-2000 02:23 AM

Mark,

are you back at work yet? Could you organise those prices we spoke of? I emailed the office but no reply as yet...

Thanks

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