Arthur said:
Maybe the head needs a touch of oil to lubricate the pins, if one is
stuck (or it may have failed).
Let me expand on what Arthur said.
I spent some time working in electronics repair, and so, I'd accumulated
a small variety of cleaners, cleaner-lubricants, etc. -- mostly in
aerosol cans.
When my new Panasonic dot printer was suffering from sticking pins, I
solved the problem instantly and permantly with one of these liquids. I
used the classic formula of the time: freon that contains a small amount
of silicon fluid. The Freon provides a liquid flush (cleaning); it
penetrates, too, and carries the silicon along with it. The silicon is
left behind. Silicon fluid is excellent for lubricating many things
_other than_ metal-to-metal. Of course, Freon has been outlawed, and
these fluids now use a different carrier/cleaner. These liquids are
quite expensive: they're mainly liquid professional tools, but you can
probably buy one or two at Radio Shack, you'll probably get better deals
and variety at a _real_ electronics supply store (if you can still find
one), but will have to buy a larger quantity.
Avoid petroleum-based lubricants for this task. These oils attract dirt,
so you'll be back with the original problem, maybe worse. The way I'd do
it is to fit the extension tube onto the spray head; spray a short burst
of the cleaner/silicon into a piece of paper towel, then let the residue
still left in the tube to dribble onto the printer pins. You may need to
do this a couple more times. Try not to let any of the stuff get onto
any other part of the printer because there may be parts and assemblies
that depend on friction to work properly.
Before you do this, load up something that works the printer hard on
your computer using all the pins -- like a page full of the letter Q; or
"Qq." Get it all set to print except for the final click. Apply the
fluid as above; then immediately do the final click to get those pins
firing as soon as possible -- the carrier may evaporate really fast
(Freon certainly does). Once when I was desperate, I bought a small can
of some sort of environmentally "acceptable" liquid at Radio Shack; it
evaporated incredibly slowly. But, anyway, you can probably dig the
logic: flush out whatever junk is causing the pin to stick; exercise it
by working it immediatlely, and leave behind a benign lubricant.
The traditional moisturizer used in ribbons, unless it's been changed,
was Glycerine. Things can gunk-up slightly when it's used; at least,
that was what happened with typewriters. So, the cleaner-lubricant may
be able to flush out what got carried in there by the glycerine. Also,
in case the sticking was caused by minute rust particles, the liquid
plus working the pins should spit them out.
How's that?
(Comments and corrections are welcomed from anyone with long enough
experience in printer repair!)
Richard
