This is topic Soundhead Problem in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Steve Scott (Member # 630) on 10-07-2001, 08:10 PM:
One of our Dolby Cat. 700 penthouse readers started malfunctioning today for no apparent reason. The tension arms won't stay steady during operation & the SRD signal can't be read as a result. From pulling open the upper tension arm, it felt sluggish.
Does anybody know what can be done to fix this? It's the reader for our biggest house & I'd like to get it fixed soon.I haven't looked inside the cover yet, but I suspect it could be a screw inside. Any thoughts?
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http://www.mullerfamilytheatres.com
Posted by Josh Jones (Member # 447) on 10-07-2001, 08:44 PM:
Does this happen on all prints?
from the sound of it, there could be a problem with the flywheel. remove the back cover and see if there are any wires, cables, screws, ect, rubbing on the flywheel. that will cause the reader to read fail.
a less likely possibility is that the flywheel bearing could be on their way south, or just a large accumulationof dirt has built up somewhere.Hope that helps 
Josh
Posted by Steve Scott (Member # 630) on 10-07-2001, 09:10 PM:
This just started on our print of Serendipity. My main concern is that the arms are wobbling too much & could scratch the soundtrack, as well as lose the SRD signal.I checked the flywheel, except for a little dust it was alright.
Posted by John Walsh (Member # 168) on 10-07-2001, 10:23 PM:
When the show ends, turn all the rollers (and sprocket) by hand and see if any are bound. Is the film from the platter bouncing around, ie: there's somthing wrong at the platter?
Posted by Gordon McLeod (Member # 33) on 10-08-2001, 03:53 PM:
Also check to make sure that the spring is intact between the 2 arms and also check the dashpot
Posted by Steve Scott (Member # 630) on 10-08-2001, 11:45 PM:
The platter is operating normally & the two looped springs are intact & don't seem in any worse shape than any of the other springs on our other cat. 700's. The metal bar that holds the arms back looks to be in the normal position when the arms are closed, so could there be a problem within one of the rollers?
Posted by Josh Jones (Member # 447) on 10-09-2001, 11:00 AM:
Does the sprocket roll freely?Josh
Posted by Steve Scott (Member # 630) on 10-10-2001, 04:25 PM:
The sprocket rolls freely & all of the rollers are cleaner than most of our rollers.
Posted by John Walsh (Member # 168) on 10-10-2001, 05:08 PM:
Gordon's got a good idea.. try the dash-pot. The lower roller arm should have some resistance to it as you swing it up and down. Compare it to the upper arm, which is just on a spring.
Posted by Mark Gulbrandsen (Member # 72) on 10-11-2001, 02:03 PM:
I have had the hole that the spring goes into get oxidized. It is the alumnium casting that actually oxidizes. Perhaps also the differetn metals don't help. I've only seen this happen in Midwest locations where it gets damp. You have to take the pad roller arm off and the spring as well and clean out the hole with a small drill bit. This caused erratic film flow through the reader.
Mark @ GTS
Posted by Steve Scott (Member # 630) on 10-11-2001, 11:34 PM:
Mark, it seems the drill bit idea was a good idea. I did notice that the dashpot was a bit rough, after running a small cordless onto it, the film stays steadier. The error rate is 3, average, if not better for that system.
Thanks for all the tips & suggestions guys!------------------
http://www.mullerfamilytheatres.com
Posted by John Walsh (Member # 168) on 10-11-2001, 11:42 PM:
Hey, this is great! We get to hear about a resolved problem! I hate it when the orginal poster doesen't tell us what finally happened!!