This is my last and, I hope, final work on the Topcat's printers traction system.
How you can see, I have removed the original stuff wich was the wheel traction,
its plastic support and I have created a support groove for the o-ring.

Original wheel.

After wheel stuff removing.

You can see only the plastic support.

Grooved!

And finally, the new wheel!

On my HP-97 the system work very well, even after weeks of not using the printer does not overlap the printed lines and drag the paper in the right way.
Only the line density has fallen from 6.2 to 5.9 lpi.
For those wishing to experience this change, the o-ring measures are:
- outer diameter 8.5 mm;
- internal diameter 4.5 mm;
- thickness 2.0 mm

I apologize for my bad english and I hope you have improvements
to be proposed, thanks in advance.

I wish you good job!

Ignazio

Well done!

Can you point me to the printer disassembly instructions somewhere? I know it's not trivial.

How did you do the modifications to the plastic parts? Which tools have been used?

Marcus

Thanks Markus,
I don't know where and if you could find the instruction, I have used only the exploded view showed in the Service Manual of the HP-97 and I tried to do it.

These are the parts of the printer, disassembled:

Disassemble the printer is not particularly difficult, you must pay attention to the thermal-head flat cable.

The tools do you need are a exacto knife and a hacksaw blade for the groove; it is not necessary to use adhesives to fix the o-ring.

Sure, it takes a lot of patience and attention. Before making this type of job, I have always completely dismantled printers to be able to clean and lubricate better.

Regards and thank you for your interest.

Ignazio

Edited: 6 May 2009, 11:27 a.m.

Thanks for the posting,

Geoff