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Topic: SPECO LP-270 Platter Misbehavior

Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-07-2000 11:59 AM

I have a platter that's misbehaving...

SPECO LP-270: Feb./Mar. 1996 vintage (non-removable brain)

The platter runs at 'variac speed' no matter what the position of the payout control arm... Not a problem at the beginning of the movie, so most people won't notice that there's even a problem until later on in the show. Then, later on in the show, the platter runs too fast and causes a wrap.

It only happens with the top deck. It is an intermittent problem.

It happened on one show and we caught it in time and were able to monitor the speed and babysit it through the show. At the end of the show I checked out the whole platter and there was nothing wrong. About a week later, the problem appeared again and caused a wrap.

Although we are still using the platter system in that house, the top deck is under quarrantine until we can be sure it won't happen again.

What I checked:

1) Correct buttons pressed.
2) Payout arm not stuck. It moves freely.
3) No dirt or crap in the bearings.
4) No metal shavings and crap stuck to the payout magnet.
5) The payout magnet isn't twisted out of position.
6) The film break switch at the bottom of the Yo-Yo (variac) isn't stuck.
7) All fuses, etc. are intact.

Last two theories:

1) Payout control PC card?
2) Sticky switch in the control box? (I HATE replacing those switches! -- Please don't be a bad switch!)

Anybody have any suggestions?

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 02-07-2000 12:22 PM

I would spray out the selector switches with contact cleaner and work them several times. Also check the solder connections on the switches for cold solder joints or a wire shorting an adjacent terminal.
You could also swap the circuit boards from deck-to-deck and see if the problems follow that particular board, but most likely I'd say you have a deck selector switch problem.

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Dave Williams
Wet nipple scene

Posts: 1836
From: Salt Lake City, UT, USA
Registered: Jan 2000

posted 02-07-2000 12:25 PM

I wish I did have an answer. I have the same problem on one of my SPECO LP-270 (removable brain). It is the middle platter and also is under quarantine. I would say the PC card is fried. I have replacement parts for mine but don't have time to work on it until may.

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"If it's not worth doing, I have allready been there and done it"

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 02-07-2000 02:07 PM

It's possible one of the magnetic reed switches soldered to the board has failed (metal fatigue from opening and closing so much).

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Michael Labbe
Film Handler

Posts: 12
From: Biddeford, Maine USA
Registered: Sep 1999

posted 02-07-2000 04:19 PM

Randy....

I have eight of these beast at one location and have very few problems with them. Don't get me wrong there not the best design ever but after 15 years and still running it could be worse. I think you may be on the right track. Where the magnet is located under the brain assy fastened to the front of the platter deck support arm is the payout control board assy. Part # 111-0021-03. This could be faulty. They are quite easy to swap out and will tell you right away if the problem is resolved. More often then not what happens is the magnet becomes misaligned with the payout control board. Not so much twisted as back and forth. Attaching the magnet assy to the payout control shaft is usually a philip screw, while holding the payout arm in the 3/4 position slide the magnet assy. back and forth as to piviot on that philips screw. This will take some time since the platter ***must be unplugged before each adjustment is made, (otherwise will will get a healthy belt from the board.)*** The idea is to have the magent adjusted so that it will engauge the motor when the control arm is at 3/4 position.
Good grief after re-reading this post I may have confused you more. Good luck...let us know how it works out. If instructions are confusing let me know, we may be able to talk through it on the phone.

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Gordon McLeod
Film God

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

posted 02-07-2000 06:10 PM

I have regularly found that one of the SCR's has shorted on the control board. Radio Shack I think still stocks them

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Stephen Jones
Master Film Handler

Posts: 314
From: Geelong Victoria Australia
Registered: Jun 99

posted 02-07-2000 07:49 PM

Having used specco platters off and on for several years this problem always crops up.
The main reason is that the magnet on the pay out arm has shifted,you will have to re alighn it with the reed switches on the printed circuit board underneath.Adjust so that the motor comes on at the or about the 3/4 position of the pay out arm,you may have to fiddle a bit to get it where you want it.My experience with the push buttons is if they stuff up the platter will either stay on or off,I have had this happen also.Another tip which can cause both take up and pay out problems with specco platters is that the rubber on the drive shaft from the motor that makes contact on the actual platter to drive it may be worn smooth causing the drive to slip as it moves the platter otherwise not enough adhesion.Just get some fine emory paper or sand paper and rough up the rubber on the shaft making sure that no particles get into the motor.you could also check the motor brushes as well.After useing speccos after a while you pick these things up.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-09-2000 02:14 AM

I've changed out the PC card under the platter. Yes, you're right about getting zapped. Just don't touch the heat sinks on the SCRs at the same time you touch anything else. (Unless you LIKE having your eyeballs light up like a pinball machine!)

The magnet is aligned 'sideways'...
If the yo-yo's down, (break-switch activated) the platter won't start up till the arm is about 1/4 of an inch from the left bumper stop. (As the manual recommends.)

If the yo-yo is up, the platter stops rotating when the arm is about 75% of the way towards the right bumper stop.

I never thought about moving the magnet in and out... I'll give it a check.

I still havent't checked the switches in the box, yet. It's kinda' hard to do during run-time. Friday morning after print build-up and before 1st show is usually the time I get to do stuff like this. I'll do it then. The big problem I have with this is that it comes and goes! Problem occurred, we baby-sat the show and when it was over we checked out the whole platter. It was okay. It ran okay for 3 or 4 days before it happened again. When I checked the platter out, it was all okay again. This is why I theorized that it might be a bad gang-switch. We've had a couple of them go bad before. (BOY! are they a BITCH to fix!) The last time the deck quit working all together. It was a burned contact inside the gang-switch. I can't see how that would have caused a platter to run at variac speed 100% of the time like is happening now. Maybe there's a "cat whisker" inside the switch box, causing a short somehow?

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John Wilson
Film God

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

posted 02-11-2000 06:11 AM

>>If the yo-yo's down, (break-switch activated) the platter won't start up till the arm is about 1/4 of an inch from the left bumper stop. (As the manual recommends.)

If the yo-yo is up, the platter stops rotating when the arm is about 75% of the way towards the right bumper stop.<<

Is that the same position of the payout for all three decks?

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-11-2000 05:07 PM

Yep, I just got done going over that platter. Everything seems to be working...

I put the yo-yo down. All 3 platters start running full-speed at 1/4" from the left bumper.

I put the yo-yo about 1/2 way up and taped it there. All 3 platters are full-speed @ 1/4" from the left, slow speed (as determined by the height of the yo-yo) in the middle, and all 3 platters turn off at about 75% of the way to the right bumper.

I changed the payout card in the top platter then checked and rechecked the magnet position.

I opened the control box, dusted it all out and checked all the wires and internal contacts that are visible. They are all good.

At this time, I still have it quarrantined. The reason is that I don't want to put it to the acid test on a Friday night. Come Monday, I'll try it out again and see how it runs.... News at 11:00!!!

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-15-2000 07:52 PM

Well, I put the platter back in operation last night and it ran well for three shows. (Two of which were on the offending deck.) At this point, I'm going to pronounce it "cured".

I have, however put the word out that the person running that end of the bldg. is supposed to go check on that platter every few minutes until we're sure (reasonably) that there won't be any more trouble.

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Chad Souder
Jedi Master Film Handler

Posts: 962
From: Waterloo, IA, USA
Registered: Feb 2000

posted 02-16-2000 10:42 PM

All 12 of my platters are the same type. I recommend looking in to the conversion kit of making the permanent payout control removable. True they are a little on the spendy side, but with the payout controls you take out, you've got unlimited parts supplies. Plus, I believe the removable controls are easier to adjust the magnets when needed, and it is _much_ easier to move film when you don't have to lift it over a control. Last, since we've switched, we've had considerably fewer problems with magnets, wraps, etc. than we ever did with the permanent. I'm not working for SPECO, but the removable controls sure make life easier, and they're not very difficult to swith.

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"All right, brain. You don't like me and I don't like you, but let's just do this and I can get back to killing you with beer." - Homer Simpson

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-16-2000 11:36 PM

Typical mgr. at your average Googolplex: "Gee, is it broken or something? Why do we need to by THAT?"

ME: "Well, because it could actually SAVE you money in the long run."

Mgr.: "We've gotta keep our budget down..."

etc, etc, etc......

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 02-23-2000 10:47 PM

Just a quick note to say that the offending platter is now pronnouned cured. It's been running for over a week and not a hint of problem.

Thanks for the advice! Film-Tech RULES!

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