TU58 / DECtape II: Capstan goo

[Tony Duell]

On Tue, Dec 7, 2021 at 10:38 PM Jan-Benedict Glaw via cctalk
<cctalk at classiccmp.org> wrote:

>   However, when I checked the two drives capstans, they're old. One
> has a crack, and as things go, they feel partially either hard or
> gooey. Are there recommendations to exchange these for new ones?

I turned a replacement hub from aluminium rod and used an O-ring as
the tyre. It only has to engage with the drive roller in the
cartridge, it doesn't contact the tape of course.

> I
> also noticed that one of the two motors rotates quite freely
> (both unconnected from the board, so I'm sure they're not magnetically
> braked) while the other ... can be turned without any unreasonable
> torque, but it won't continue to spin at all.

Hmm... Try a drop of light oil on the bearings first.

I'd then try running the motor off a bench supply and measuring the
current it draws. If the 2 motors run properly like that and draw much
the same current then there are no problems.

-tony