6 Oct
2005
6 Oct
'05
5:10 p.m.
On Thu, 6 Oct 2005, Tony Duell wrote:
Yes... The reader contacts (those operated by what Creed would have
called the 'peckers' :-)) are effectively in parallel with the keyboard
contacts. Both devices give a parallel output, of course. They then link,
via wires in the call control unit, to the distributor disk, which
serialises the data.
The reader has a big solenoid at the bottom that lifts the peckers to
read the tape and then, when it gets de-energised, operates a ratchet to
advance the tape. This is poweed by the PSU in the stand (warning : this
is not isolated from the mains supply!), and is controled by the leaf
contact on top of the transmit shaft. To operate the reader, a little
solenoid there is energised. This releases the clutch lever, causing the
transmit shaft to rotate and turn the distributor bush. That lever also
closes the leaf contact, energising the reader soelnoid. After each
character (rotation of the transmit shaft), the lever is forced forwards
again, and will latch there if the trip solenoid is de-energised (the
reader is turned off). Of coruse as it comes forwared, it opens the leaf
contact, de-energising the reader solenoid and advancing the tape.
There's a cable harness that attached to the
reader. It splits into 3
sections. One goes down to the stand and plugs into that module you've
found. This is the power supply for the solenoid in the reader itself.
One little branch connects to the leaf contact switch on top of the
transmiter shafter in the typing unit. And the 3rd branch plugs into the
back of the call control unit. It's that last one I want you to unplug.
Right, this is what I eventually figured out. I didn't realize the reader
cables banched off to different points. Once I found that and unplugged the cable to the call control unit the problem went
away, isolating the
problem to the reader. I then removed the reader and examined it more
closely and saw the tine out of place. How it got that way is beyond me.
That was going to be my guess, actually, but I never post guesses without
some evidence (that is, getting you to do some tests first.
-tony