3 Sep
2011
3 Sep
'11
11:37 a.m.
Hi guys,
I've just acquired a HP 7470A in a lot with some other gear, and it
Nice find!. Which version is it? There are 3, HPIB, RS232 and HPIL (the
last being by far the rarest). Alas you can't easily convert one to
another, there's one PCB inside, and it differs between the versions.
seems the rubber paper feed rollers have deteriorated
somewhat. They've
acquired a gummy consistency, and are covered in flat spots...
I assume these are the little rollers on the clamp arms above the plotter
deck. You are going to ahve fun... I've just looked at one of mine, and
the rollers are tappered (they are designed to keep the paper taut as it
moves). I don;t think a normal cylindrical roller is going to work.
Whether a thin 'rubber' coating (for example heatshrink sleeving) on a
tapered hub would work, I don't know. I think I'd try that first, because
it's not hard to make.
Turning a tappered rubber roller is possible, but rubber is not easy to
machine. It helps to cool it, but not too far (I am told that solid CO_2
is about the right tempeature).
-tony