Film-Tech Forum ARCHIVE: Converting a Cat 280 SR to a Cat 280T SR

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Topic: Converting a Cat 280 SR to a Cat 280T SR

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-31-2001 04:33 PM

If my memory serves me correctly in this matter it involves installing a resistor on the CAT 280. Does anyone remember what value and where on the Cat 280 and or any other mods that had to be done?
Thsnks,
MArk @ GTS

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Christopher Seo
Jedi Master Film Handler

Posts: 530
From: Los Angeles, CA
Registered: Jun 99

posted 09-01-2001 12:03 AM

I can't be of any help here, but I'm just wondering, what is the difference between a 280 and 280T? Is it just that the 280 can be used for recording and playback but the 280T for playback only?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-01-2001 08:59 AM

I don't think there is any difference at all except that the 280T has something added to lock it into playback mode. If my memory serves me correctly plugging it into a 50 or 200 will not automatically put it in playback, but I may be wrong here.
MArk

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 09-01-2001 03:16 PM

It is even more minor than that. On some of the various card frames within the Dolby empire, not having a Cat. 280T can cause greef due to the resistor Mark mentioned. Certainly Ken could enlighten us.

Steve

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"Old projectionists never die, they just changeover!"

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Ken Jacquart
Film Handler

Posts: 82
From: San Francisco, CA, USA
Registered: Mar 2000

posted 09-04-2001 04:53 PM

okay here's the deal...

On the Cat 280T card, there is a space for a tiny jumper labeled J801. A Cat 280 card comes with this jumper in place. It is located directly next to the letter "A" on the edge connector, but actually completes a path out to pin "1" directly on the other side of the edge connector. The problem is, if you plug the card in to an appropriate cinema processor after you have installed this jumper, it will remain in record mode due to the fact that pin 1 is kept high. If the modified card is to be used in a Model 364 frame, there are a few resistor issues, but I won't go there for now...

ken

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-04-2001 05:35 PM

Thanks Ken!
Something definately did not sound right in this theatre. That is what I suspected as they bought these 280T's from a local Pro Audio company. Will be there later this week so I'll check them. The odd thing is that this is a CP-50 with alot of upgrades and it also has a 113C automation interface card. When you run in what should be format 05 it sounds pretty good. In format 04 which is where I always run a CP-50 with 280T's it sounds strange. Does the 113C card do this switching without removing the jumper? No need to delve into the 364 here.
Mark @ GTS

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-05-2001 10:16 AM

Ken,
Here is what I found on the cards. Both are very early cards. One is SN 3 308 and mthere is no place for a jumper by pin A. However there is a jumper from T to the hole right below T on this card. Could this be doing the same thing as having the jumper at A?

On the second card which is SN 17 856 there is a jumper at A which I will remove.

Apparently some minor changes were made to the CAT 280 cards after the first few hundred made. If possible can you fill me in on this?
Thanks,
Mark @ GTS

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-07-2001 12:41 PM

Had some time this morning and ohmed out the traces on both cards. One card, the earlier one has a slightly different layout. But the spot for the jumper is there. It is just rotated 90 degrees and slightly above the pin A position so looking at it is a bit confusing. So as it turns out one card had the jumper and the other one did not. Both now have no jumper, and I have marked them as 280T cards. Sound is now also great running in format 04.
Mark @ GTS

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Rick Long Jr
Expert Film Handler

Posts: 211
From: Toronto, Canada
Registered: Jul 2000

posted 09-08-2001 07:46 PM

Here's a stupid question that I'm sure I once knew the answer to: What is the correct position for that little switch on the 280T's when used in a SRA5. Is it different when using them directly in a 200 or CP-50?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 09-09-2001 01:38 AM

And the answer is....

It doesn't make a damn bit of difference in theatre appliciations!

Steve

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"Old projectionists never die, they just changeover!"

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Rick Long Jr
Expert Film Handler

Posts: 211
From: Toronto, Canada
Registered: Jul 2000

posted 09-09-2001 11:56 PM

Thanks Steve!

-Rick!-

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-10-2001 09:29 PM

Steve, Whats that I'm looking at on your collar? That is a wierd shot!
Mark @ GTS

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Richard Hamilton
Phenomenal Film Handler

Posts: 1341
From: Evansville, Indiana
Registered: Jan 2000

posted 09-10-2001 09:36 PM

Collar??? I thought you were looking at his butt!

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 09-11-2001 12:32 AM

According to the Film-Tech Drink photos from ShoWest 2001, Mark is looking at my shoes...Mark lets face it...you are just too damn nosy...keep your eyes on your own body. People are starting to talk

Actually, I'm wondering why that photo was chosen (not by me, btw)...I look rather beat!

Steve

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"Old projectionists never die, they just changeover!"

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Brad Miller
Administrator

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

posted 09-11-2001 03:23 AM

Steve, you didn't like the other photo of you, remember? I'll post it here to embarass you anyway.

(Now we all know why you hate platters. )

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