2012-05-25 N_Cook wrote,
Proper cloth upholstery tape , not duck/duct tape ,
wrapped around the (near) end of the ribbon, to bulk up

Good idea. The primary difficulty is that the reinforcing cardboard
glued to the surface of the ribbon projects only about 2 mm out of the
connector when the end of the ribbon is fully inserted. If I reinforce the
ribbon too much, the strain between the reinforcement and connector will
only be exagerated. The design is intrinsically bad, as if they intended
it to be a weak point. (What's new?) I wrapped a turn of 3M Magic Tape,
overlapping the cardboard as far as possible without interfering with
assembly.

By the way, has anyone ever built one of these ribbons?
What is it, polycarbonate or Mylar with a film of copper?

2012-05-25 William Sommerwerck wrote,
I was joking [about WD-40]!

Too late. A film of WD-40 was on it for the previous weekend. Upper
two pins still frozen.

2012-05-25 Jeff Liebermann wrote,
Brass plate? All the Panasonic print heads I've seen have a plastic
guide block. Care to disclose the model number?

Panasonic KX-P1180 Multi-Mode Printer. The frame which holds the guide
plate is black plastic. Certainly the plate is brass. Might photograph
the next one I overhaul.

You'll wreck it if you take it apart.

Not necessarily. Work carefully.

Inside are 9 levers, which act as a solenoid.

Correct. The lever acts as a teeter-totter. Appears to be silver
solder fastening the pin to the lever.

It's these levers that are probably stuck. Rust is a
potential problem, which alcohol won't touch. Maybe WD40.

All levers are free but the tip of each of the upper two pins is
rusted into the brass guide plate. The solenoid is counteracted
by a tiny coil spring. WORK ON A CLOTH. If a spring is dropped
it's unlikely to be found or replaced.

After soaking with isopropanol and with WD-40, still no sign of
the frozen pins working free. I lifted out the 7 free pins.
Then put the tip of a slender straight blade screwdriver under
the lever of pin 8. A gentle twist and pry broke the tip of the
pin free. Likewise for pin 9. I cleaned the pins with an old
Scotch-brite type scouring pad. For interest, put a pin under a
low power binocular microscope. The striking end is pitted with
corrosion.

This head has a clear plastic washer under the levers where they
converge at the center. Presumeably for cushioning if there is
too much clearance between the pins and the paper. Be careful to
keep the washer in place and in the correct orientation.

Just shove it in straight. If you must use pliers, wrap some
electrical tape around the plier jaws.

Pliers are too risky. Just grip tightly between fingers and thumbs,
close to the connector. Align carefully to avoid kinking. Helps
start one corner first and rock from side to side slightly. Also
I put a film of zinc oxide grease on the tip of ribbon, invisibly
thin.

Some force is required.

Oui..Definitely not a good design. Did this result from inexperience
of the designer or from intention?

2012-05-26 N_Cook wrote,
... impact printers play a tune percussively ...

A dot matrix printer is also reliable and economical. Why not keep
it working.

Thanks for the discussion everyone, ... Peter E.