From: Saffron walden.united kingdom
Registered: Jun 2014
posted January 11, 2015 11:41 AM
Hi, can some one please help i have a bell and howell tq3 projector that was working ok but not now if you put a 2200 foot spool on the back the picture jumps constantly but if i use a 1600 spool on the back it works fine seems like some kind of weight problems does anyone know what causes this is to happen thanks ?
From: Bristol. United Kingdom
Registered: Oct 2007
posted January 15, 2015 02:33 AM
If a lighter take-up spool works OK but a heavier spool causes picture jump, then it is possible there is a problem with the take-up tension.
Tension on a Bell & Howell is varied according to the weight of the take-up spool. There is a cloth belt which pulls more tightly on a rubber drive shaft as the weight increases. The belt should have a slight slip around the rubber covered roller which itself is constantly driven.
Over time, the rubber becomes sticky, some sticky deposits are picked up on the belt. The two therefore do not allow the necessary drive slip.
It is possible that the heavier 2200' foot spool is causing the drive to lock. This will cause all of the mechanism to object and there may be vibration eventually at the cam, causing the claws to make the picture jump.
To rectify the problem, examine the belt and see if there is a rubber deposit on it. If so, reveres the belt (i.e. turn it over). Check the surface of the rubber roller. If it is sticky you could remove the rubber roller completely from its metal shaft. A scalpel is a useful tool. (Watch your fingers.)
I may be wrong in my assumptions. But do check out the rubber roller and belt before doing anything else.