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Topic: CNA-100 problem

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-17-2016 04:15 PM

Nothing to apologize abut Sean. Neither of us designed them. They had their weak spots and perhaps before you got to working on them were the teeny tiny micro switches they used in the payout heads. So you had several weak aspects there. Later on there was a retrofit for the pay out heads, but it's been so long I don't remember what it entailed. I'm just glad they are all gone.

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 08-18-2016 05:30 PM

They replaced the micro switch with an IR emitter/detector assembly and a reflector. You "timed" the payout head by moving the reflector to where it didn't return too much IR or it wasn't so far out that you got no reflection. I remember they worked best if you left a payout unit to a particular platter but projectionists loved to move them around the complex. They also used an easily broken pin to orientate the payout head which when broken would allow it to spin freely and unscrew the 1/4 phono plug. The funny thing is after all the years I still remember the model no. NXP-3000 or NXP-3500 (for the 5 tier) because I wrote SO many service reports on those. And I only had them in one 10 screen not all over my territory like you did.

I would still like to know who at Neumade decided using a 1/4 phono plug was a good idea to connect payout units to the platter. At one point I considered re wiring them all with another type of quick disconnect but never found anything suitable besides rebuilding the entire unit to take strong payout units.

I did have quite a few NXR-3000's too which was pretty much a copy of the Potts Alpha platter/strong AP platter.

But then again I also had my nice National Amusements locations with equipment outfitted Louis Bornwasser (sp?) that were totally trouble free beside the odd crossover here and there on the Haffler (I think) amps. I actually serviced the old Dedham, ma location outside the corporate office before they tore it down and built the mall and new cinema and that location still had the original automations from the 60's which I can't think of the name but they used diode pins to step down events and functions, relays and a cam timer. I heard they were hand wired by (I'm sure) nice older ladies I'm England. I'm not sure any two were wired exactly the same!

Boy, do I miss the good old days. [Smile]

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 08-19-2016 03:14 PM

That's right! I had completely forgotten (purposely) about those.

On the Strong/Potts micro switch payout heads we developed a triac board that was controlled by the micro switch. This way the micro switch was not doing all the heavy switching work, but the triac did. Lead free switches lasted way longer that way.

Mark

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