GS 1200 Xenon issue

[Paul Adsett]

That's great news Clive - well done!
Those auto thread micro switches seem to need replacing every few years, and GS1200 users should consider that to be a periodic maintanance task. They act weird when they are failing. If you check across them with a meter they seem to be functioning just fine, but when they are failing they just cannot carry the required current to trigger the auto thread solenoid. Must be corrosion or oil/grease on the internal contacts.
These same switches are present throughout the GS1200, so if you are having intermittent problems with any of the various projector functions then replacing the appropriate subminiature micro switch is often a good bet. Dirty or oxidized switches/contacts account for the bulk of GS1200 problems.

[Clive Carmock]

Spot on Paul - I replaced the rear microswitch while I had the machine apart. My auto thread issue turned out to be something else though. So in a bit more detail in case it helps someone in the future..... On the front microswitch - the one that is engaged when the thread button is pressed - there is a small silver coloured metal lever that holds that front switch engaged until the auto thread is released. What was happening in my case is the auto thread was releasing when I pulled the film as it emerged near the take up spool. However the lubrication on the pivot point of this lever on the front microswitch had got sticky and it wasn't dropping down quickly, hence it would keep the front microswitch closed.

This had the effect that the film path would open to the run position, but the magnetic head pressure pad and the dowser would not operate. eventually the lever would drop down enough and things woudl operate, but it would take around 5-6 seconds.

The pivot point for this lever is behind the upper white gear, that drives the upper sproket. Rather than remove that and risk dropping the circlip into the machine I managed to get a drop of oil onto the end of a screwdriver and touch the pivot of the metal lever. Repeated this a few times and then used the same screwderiver to move the level up and down severl times freed it up.

Now when I tug the film to engage the rear microswitch the front one will immediately disengage due to the lever moving freely.

I still don't know why the machien wouldn't play back magnetic tracks, but was fine with optical - but can only assume clearnign the switches and contacts etc on the amplifier board cured that.




One other point and I wonder if this is just how it is... when I turn the power on to the Xenon machine there is a loud pop from the speaker as it powers on. On the non Xenon machine this is much quieter.

I wonder if this is just how the Xenon machiens always were? I know they use a different amplifier chip.