ASR-33's and Brain Dead "Repair" man...

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Mon Aug 23 17:38:18 2004

>
> >>>
> >>> If pressing a key doesn't cause the distributor to spin,
> >>> then there's a mechanical problem. You want to investigate
> >>> the linkage that starts at the ekyboard (the metal strip
> >>> that the H-plate slots into should turn counterclockwise
> >>> seen from the left side when you press a key, and is
> >>> returned to the clcokwise position by the H-plate). Then
> >>> trace the linkage via the H-plate to the clutch at the
> >>> back. This should engage when the key is pressed.
> >>>
>
> I always get turned around with spacial relationships in the written
> word.....
>
> Comparing the linkage position to the one on my working unit. It is indeed
> in the "deactivated" position and does NOT move when a key is pressed [as a

Am I correct that when you press the 'Here Is' key, the distributor does
turn? If so, then the clutch can be released (and presumably latches up
correctly).

> clarication, the "far" ent of the linkage extends through a slot on the
> front of the keyboard assembly. On the working unit, qhen no key is pressed,
> the end is down, it travels up when the key is pressed and returns down
> when the typing unit finishes its cycle. On the new unit this end is always
> in the down position].
>
> Attempting to move the linkage (but not overly forcing it] is futile.

Don't force anything. You will just cause more damage.

What I would do next is remove the transmitter shaft. To do this, remove
the typing unit from the chassis pan, then take off the distributor brush
holder (central screw, but don't let the brushes fly out) and the
distributor PCB (3 screws).

Then take off the motor (2 screws at each end) and free the drive belt
from the sprocket). Take off the bracket over the top (180850 in my
partsbook), then the bracket over the bearing (180998). Lift out the
shaft complete with the belt (don't forget to slip this on when putting
it back!) and the bearings.

Youi can now see the trip ling. I'd be inclined to disconnect the 186261
link at one end to see if it's the front end (186264) that connects to
the H plate or the rear end (186254 and related parts) that's jammed.
Then you can dismantle the appropriate part.

>
> Visual inspection of the path [at least what I can see without moving the
> typing unit out of the chassis bay], does not reveal anything. Are there any
> typical binding points? Should I be thinking about a seized clutch?

If the link won't move at all, it's not the clutch. The transmitter shaft
will clearly turn, or the receive side couldn't do anything (the motor
drives a sprocket on the transmit clutch drum which also carries a gear
which meshes with one on the receiver shaft).

-tony
Received on Mon Aug 23 2004 - 17:38:18 BST