N_Cook wrote in message
...
Discovered what the original problem was.
A rectangular tunnel between the colour wheel and the first lens, going
across the airpath of a fan. Made of silvered microscope slide glass , 4
pieces forming a rectangular tunnel about 6 x 8mm but the glue at the
corners failed with time or heat and the retaining spring pushes one edge
in
a bit.
Removing the spring and the tunnel collapsed, i'm surprised the fan air
didn't totally disloge them.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




Before wasting my time rebuilding the 30mm long 4 x 3.7mm internal bore
light tunnel I need to establish whether the bulb is actually failed or a
problem with the drive .

Putting a 50 watt floodlight mercury discharge lamp across the feed, either
way round produces nothing.
Putting a 110V neon across the feed there is a constant orange glow but no
initial flare - too short to be seen ?.
Putting a 150 watt spotlight discharge lamp there, nothing.
Even tried a 9 inch standard fluourescent tube in all orientations.
Anyone know what the trigger voltage duration would be? I'm loathe to
connect up a scope in such circumstances, how to check there is a high V
trigger pulse ?

Would you expect to see black colouration in the active part of the original
lamp or some other sign of problem ?


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/