Thanks to everyone who answered my pleas for help. As several people
have suggested, the culprit was the cloth storage system. I think
that my sandpaper beam has lost enough of it's tooth to be a factor in
the problem. The beam works if the cloth storage is working, but if
the pull from the storage system is reduced too much, it doesn't work.
I should have seen this, and actually anticipated it, but I had a few
senior moments. The story on the cloth storage system on this loom is
About a year ago, I was weaving along, and suddenly the weight hit the
floor. I checked the pawl and ratchet, cord, etc. All looked OK.
Some disassembly and more inspection showed that the wooden disc that
the cord rolls up on to raise the weight was rotating on its axle.
Further, the outer end of the axle had rusted, the increase in size
caused by the rust would not let the axle move through the loom frame,
and I could not get the disc off the axle. So it didn't work and I
couldn't remove it to fix it. I wondered if I could use this in a
"manual" fashion; just rolling up the cord whenever I advanced warp.
The answer was yes, it worked. However, I realized that the disc
would continue to loosen, and eventually would not hold enough tension
to work. I hoped at that time that I could get the disc off the axle.
I promptly went back to work on the loom, and forgot about this entire
train of thought. The weight went in a corner, a dog put a dog bed on
it, and it became habit to tighten the cord. When it stopped working
I didn't have a clue until I saw the posts about the cloth storage. I
was able to work the disc off the axle, pull it through the frame,
reglued the axle to the disc (I drove the rusted end of the axle into
the disc) and all is well until the next crisis. Thanks again!