DC300 Tape Repair

From: Wayne Smith <wsmith_at_gj.com>
Date: Tue Aug 17 21:08:52 1999

>>> Tony Duell <ard_at_p850ug1.demon.co.uk> 08/17 6:01 PM >>>
>
> Upon the date 05:01 PM 8/17/99 -0700, Wayne Smith said something like:
> >What's the best way to replace a broken belt in a DC300 tape cartridge? Is
> >there a source for new belts?
>
> Not likely unless there was a real unusual need and someone already
> supplies them. Normally, the mfr (3M, Dysan, or whoever else made them)
> figures the user will typically throw out a defective cart and use a new
> one. Hence, the assumption there's likely no aftermarket supplier,
> especially now since DC300's have been out of popularity for several years.

In my experience, spares for tape cartridges are impossible to obtain,
other than by dismantling a new cartridge. This is worth doing if you
have a defective catridge with some important data on it.
 
> Best way to deal with this is to find an unusable tape with a good belt and
> very carefully remove it and very carefully replace it on your defective
> one. Probably should find one of the same manufacturer just to be safe.
> It's stretched rather taught and will be a real circus to replace. Got
> three or four arms hanging off you? :) Tony, have any thoughts on this?

Argh! (that's me remembering what happens when you try to do this).

The belt runs from the 'drive puck' (the roller that's driven by the
capstan in the drive), between the 2 tape spools (it rubs on the outer
layer of tape on both spools, thus maintaining the tape tension, and
causing the tape to move at constant speed), and then round one or two
idlers. The better cartridges have a fixed idler (on a post fixed to the
baseplate) in the bottom corners. Some lesser cartridges have a
'floating' idler between the 2 spools at the bottom. That sort is a right
pain to rebuild, and some of them were glued together (particularly on
the smaller tapes), and these will drive you mad!

OK, assuming 2 fixed idlers and screwed-together housing. It's best if
you have 2 new tapes - one to take to bits for spares, the other to show
you where all the bits go.

Start by undoing the screws on the bottom of the cartridge, and pull off
the cover. Remove the door and its spring. Take off the empty-ish spool
(unwind the few turns of tape if necessary), the idlers, drive puck and
belt. Take off the full spool, making sure you don't spill tape
everywhere.

Clean up the rollers and housing.

Now to reassemble. Put the full spool on the 'supply' side. Put the drive
puck, idlers and belt in position. The belt will be fairly taught even
now, and should stay in place

Drop the empty spool over the other spindle. It won't drop down as the
belt gets in the way. Using a cocktail stick/plastic spike/etc, hook the
belt round the spool.

Evertything will fly off (:-(). Try again, and after about 5 goes you'll
get it in place.

Run the tape round the guides and put the end in the gap between the belt
and the empty spool. Hold everything in place and carefully turn the
drive puck. Keep on guiding the tape until 2 or 3 turns are wound on.

Counter-rotate the 2 spools to tension the tape. You will have to force
them against the friction of the belt.

Refit the door and spring. Often you can fit the spring into a hole on
the bottom of the door, tension it, and hook the end into a slot on the
door. Then drop the assembly onto its post, and finally release the spring.

Put the cover one, and fit the screws.

Wind on the tape a few more turns, and try it in the drive. Start by
'retensioning' the tape.

-tony

>>>Thanks for that great description, Tony. I don't know whether you've inspired or depressed me. ;-)

Wayne
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Received on Tue Aug 17 1999 - 21:08:52 BST

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