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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Optical Sound Troubleshooting Help (Page 1)

 
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Author Topic: Optical Sound Troubleshooting Help
Martin McCaffery
Film God

Posts: 2481
From: Montgomery, AL
Registered: Jun 99

- posted 07-20-2009 01:03 PM      Profile for Martin McCaffery   Author's Homepage   Email Martin McCaffery   Send New Private Message       Edit/Delete Post 
SH1000 soundheads, CP650, Kelmar basement readers, duel projector

Problem on single projector

Digital sound is fine. Optical is all over the place from muddy to garbled with perfectly fine parts in the same scenes. Discovered it this weekend while showing the Breakfast Club. Very new print. Dolby A. Going to mono masks, but doesn't get rid of the problems

Digital trailers are fine on that machine in digital, same problems in A and SR.

Brass in the music totally falls apart. Molly Ringwald sounds like she's gargling, but only in the upper register. Some scenes sound like they are in a barrel.

Quick checks don't yield any results. Buzz track fine. Dolby 69P slit loss shows no problems.

Where to look next?

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 07-20-2009 01:19 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
What is the error rate on the digital? Is digital a basement reader as well? If the error rate on digital has gotten higher, then it's a mechanical issue.

In order of probability:

Problem sounds like an issue with either the lateral guide roller assembly, which could be not closing properly (especially if the symptoms came on suddenly) as the lever to open it can twist on the shaft so that the latch pawl in the back won't seat properly.

The lateral guide rollers could be stuck (remember that one flange should be able to move slightly on the shaft to allow for splices and worn film).

The roller on the lateral guide that touches the film may have dirt build-up or a piece of tape or film stuck on it, or may be worn out.

The bearings on the sound drum may be going bad.

The flywheel on the sound drum shaft may be loose or rubbing on something.

Could also just be a bad print. Try another film on the same machine if possible.

Finally it could be an impending electronic or power supply failure of the Kelmar basement reader. (Least likely.)

Those are the things to check out.

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Demetris Thoupis
Phenomenal Film Handler

Posts: 1240
From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001

- posted 07-20-2009 02:22 PM      Profile for Demetris Thoupis   Email Demetris Thoupis   Send New Private Message       Edit/Delete Post 
Ermm sorry but he says that he has a problem in optical sound not Digital! Is the sound drum spinning fine or is it having a hard time spining?

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Martin McCaffery
Film God

Posts: 2481
From: Montgomery, AL
Registered: Jun 99

- posted 07-20-2009 02:36 PM      Profile for Martin McCaffery   Author's Homepage   Email Martin McCaffery   Send New Private Message       Edit/Delete Post 
Sound drum.

The screw holding the flywheel to the shaft fell out, so the drum was slipping.

Now have to find a new screw and get it in there.

Anyone ever have that screw come loose on its own before?

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 07-20-2009 04:28 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
quote: Demetris Thoupis
Ermm sorry but he says that he has a problem in optical sound not Digital! Is the sound drum spinning fine or is it having a hard time spining?

Errm sorry to you too sir, IF the digital is a basement reader it WILL be affected by the sound drum issue..by showing increased error rates. As long as the error rates stay low enough, yes digital will still play without major audible issues. Try it on any of your machines, use your finger to drag on the scanning drum of any reader and watch the error rate shoot up.

Martin, if memory serves that screw is an 8/32 thread. You can temporarily substitute any 8/32 screw long enough to pass through the flywheel and shaft. I think one that's 1 1/2 inches long will do the trick.

I may also have the proper screws in my stock, if you can't find or get one send me a PM and I can send the part to you.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

- posted 07-20-2009 07:07 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
quote: Martin McCaffery
Molly Ringwald sounds like she's gargling
Thats nothing new she always did sound that way!

I bet you have oil in the analog sound lens assy...

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

- posted 07-20-2009 09:37 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
quote: Tony Bandiera Jr
8/32 screw long enough to pass through the flywheel and shaft. I think one that's 1 1/2 inches long will do the trick.
On that scanner drum shaft, there should be a thrust washer inbetween the flywheel and scanner drum bearing.

Have some one hold the scanner drum in while you do the flywheel -it's not too fun trying to put on one of those fluid filled flywheels to get the holes aligned up when the scanner drum shaft moves in on yas.

I just did a main drive seal on a XL/SH1000 setup and if you don't think that was fun getting that flywheel back on by myself when I couldn't reach around to hold the scanner drum in too well..

I've seen so may regular 8x32" screws used that weren't of stock used in holding down the flywheels on these things ...

-Monte

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

- posted 07-20-2009 10:10 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
quote: Monte L Fullmer
I just did a main drive seal on a XL/SH1000 setup and if you don't think that was fun getting that flywheel back on by myself when I couldn't reach around to hold the scanner drum in too well..
When you come down to BYU I have a good trick I'll share with you that makes putting the flywheel back on a snap!!

Mark

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

- posted 07-20-2009 10:15 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Sounds like a plan - I could stood to learn some new tricks with Simplex units and sound stuff in general ... thx - Monte

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Martin McCaffery
Film God

Posts: 2481
From: Montgomery, AL
Registered: Jun 99

- posted 07-21-2009 08:44 AM      Profile for Martin McCaffery   Author's Homepage   Email Martin McCaffery   Send New Private Message       Edit/Delete Post 
Monte, I know what you mean about getting the flywheel back together. Yesterday I discovered a way to do it in under a minute. The secret is an extendable pickup magnet (one of those things that looks like an car antenna with a magnet on the end).

Hold the screw with the magnet, push the flywheel until the holes line up, insert screw into the proper hole, let go of the flywheel and there will be enough pressure to pull the screw off of the magnet.

Note to people doing this for the first time, there is a big hole and small hole. Put the screw into the big hole and push thru. The screw is screwed into the small hole on the other side.

Don't know if this was Mark's trick, but it worked for me.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

- posted 07-21-2009 10:22 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Martin; I just reach around with the projector door closed. Louis

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Martin McCaffery
Film God

Posts: 2481
From: Montgomery, AL
Registered: Jun 99

- posted 07-21-2009 11:25 AM      Profile for Martin McCaffery   Author's Homepage   Email Martin McCaffery   Send New Private Message       Edit/Delete Post 
You clearly have better eyesight than I [Wink]

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Demetris Thoupis
Phenomenal Film Handler

Posts: 1240
From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001

- posted 07-21-2009 02:09 PM      Profile for Demetris Thoupis   Email Demetris Thoupis   Send New Private Message       Edit/Delete Post 
quote: Martin McCaffery
Digital sound is fine.
Sorry Tony but which part of that did you not understand?

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Tony Bandiera Jr
Film God

Posts: 3067
From: Moreland Idaho
Registered: Apr 2004

- posted 07-21-2009 04:45 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
Demetris, what part of the following did YOU not understand?:

quote:
IF the digital is a basement reader it WILL be affected by the sound drum issue..by showing increased error rates. As long as the error rates stay low enough, yes digital will still play without major audible issues. Try it on any of your machines, use your finger to drag on the scanning drum of any reader and watch the error rate shoot up.
Because even with flutter that would be very bad in analog, the digital WILL still play acceptably, up to a point.

That is why I asked if the digital had a higher-than-normal error rate.

Like this:

quote:
What is the error rate on the digital? Is digital a basement reader as well? If the error rate on digital has gotten higher, then it's a mechanical issue.
Which, by the way, if you read Martin's posts, you will see it WAS a mechanical issue.

Please try to read ALL posts carefully before coming back with smart-ass remarks.

I have over 26 years experience as a service tech and one of the many things I have learned over the years is to get ALL the facts , even if it doesn't seem to be related to the problem at hand. It saves a lot of time.

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

- posted 07-21-2009 05:45 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
May I add a side comment on this issue on SR-D above: I tend a small 4plex that has SR-D in one house. Yet, they have a BACP penthouse reader.

They off and on experience occasional digital error rate problems were it's close to fail.

I look over their system and notice something that could be an attribute to this above mentioned condition that they presented to me: On their 5star head, they're using an induction motor, not a sync motor..

I told the owners that the error rate issue could be coming from having the induction motor driving this setup since they do have slight voltage fluctuations within the building. And with voltage fluctuations will cause film speed variances across the reader which the end results is the higher error rate to an occasional dropout in digital all together.

I left it up to them on what they want to do ...

-Monte

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