[GreenKeys] 28 ASR/Dometop - Why does the motor pinion gear break?

[Jeff G]

So let's start some discussion and things to look at - Why does the motor
pinion gear on our 28 Dometop (tty #2) at the ship keep breaking, and how
can I "test" for it? I need to solve this for sure before putting any more
45 baud gears into it, and for now, I'll prob put the 75 baud set back in
temporarily.

Originally I suspected the intermediate gears were never aligned/adjusted,
but in swapping the latest gear set, I made sure the gears were meshed well
but not tight. I also took that assembly apart and re-greased the bearings
on it with mobile-1 grease. The printer was printing great, in fact,
SOMEHOW, it was still going despite half the pinion gear being completely
missing! (The intermediate gear survived undamaged as well).

In both cases, the unit was on/running for a while (first was sitting idle,
this time it was printing) and in both cases, I came back to it making
noises after the gear went.

Now, I'm suspecting either the printer or perhaps the TD is adding more
drag than normal, causing both the gear to be under load, and in the case
of the TD, the drag causing the motor to get hotter than normal. In this
case, would it be normal to check the amount of current the motor is
pulling? Next time I go in (which may not be for a couple weeks), I'm also
taking a laser temp gun to take a reading off the motor with just the TD on
it. There is a capacitor on the LEU? that I'm not sure is part of the motor
or not (I think I'm gonna say no). Also the electrical filter at the bottom
was bypassed as that blew up too. (This unit is definitely giving me a
college course on TTY).

The next thing is - I was originally running the printer with no screws in
the print mechanism (but solidly seated). Both cases it wasn't until after
I screwed down the printer with a couple screws on opposite corners did the
gear break, so I'm wondering how the printer gets adjusted to the
intermediate gear, since there's no way for me to adjust that with the
printer in place. (I think)

Without going through the 1900 page manuals, are there any temperature
specs for the motors?

Any other ideas? You guys are the experts! :-)

Jeff
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