Weird scanner behavior

[buffo]

If memory serves, that projector had DT 40's in it. And DT 40's are known to have issues with the poly switch.

Hank: Try reducing your scan angle by half and power it back up. If it's OK, then it's definitely the poly switch. And even if it's still hosed, it could still be the poly switch, although with half the scan angle it should reduce the current draw enough that the switch won't trip...

If the scanners really are toast, you can replace them with a set of PT-40's for less than $300. But I suspect that the scanners are fine. Try the reduced scan angle and report back here.

Adam

[HankLloydRight]

Hank: Try reducing your scan angle by half and power it back up. If it's OK, then it's definitely the poly switch. And even if it's still hosed, it could still be the poly switch, although with half the scan angle it should reduce the current draw enough that the switch won't trip...

Thanks. I was running beam shows with max width on both projectors (including "Rising" ha ha) right before the Spider projector crapped out. The scanners returned to normal performance right after I power cycled the projector, so it sounds like the poly switch like DZ mentioned above. I haven't opened it up yet to see if the scanner is physically impaired, but I will. Is the poly switch part of the scanner itself, or on the driver board?

[buffo]

The scanners returned to normal performance right after I power cycled the projector, so it sounds like the poly switch like DZ mentioned above.

Absolutely. If after a power cycle, the scanners behaved normally, then it is definitely the poly switch. Your scanner bearings are fine.

I haven't opened it up yet to see if the scanner is physically impaired, but I will.

No need. If they were impaired, the pattern would have looked just as bad after cycling the power.

Is the poly switch part of the scanner itself, or on the driver board?

It is a small electrical component on the board (the scanner amp). It is like a circuit breaker - if you pull too much current it "trips", greatly limiting the current to the amp, but after a power cycle it is supposed to reset itself. It is this limited current that causes the pattern to look like hash. Replacing one is fairly straightforward, but in the mean time if you just back off on the scan angle a bit you should be able to continue to run shows without any further issues.

But yeah, the definitive cure is to solder a new poly switch onto each amp (there is one on the X amp and another one on the Y amp).

Adam