[GreenKeys] Decoding the function in a Teleprint modified 33ASR

[tomas at tlec.se]

Dear group.

I have spent some time, trying to understand what the German company
Teleprint did with the electronics in 33ASR.

And I think I am starting to get my head around it.

There still a few things, that is pretty unclear, However I am getting
there, hopefully.

Please don't get upset if I am not using the correct names on the various
items, I'll hope you will understand it anyway

Inside the CCU there is 5 PCB's

BS270 Local line PSU (I assume)

BS230 Selector solenoid amplifier

BS263 Automatic motor control

BS241 Reader PSU

BS292 Remote control card (well, that's what I call it anyway.

The local/Line switch has only two positions, local or line.

There is two additional single throw switches on the CCU fase-plate,
Power-switch and a Reader Switch.

Keyboard, printer etc seems to bee box standard, However, the unit is for
the European market, hence 50 HZ, but printing on the motor says "Only 60
Hz"

Since the motor runs slower (3000 RPM instead of 3600), I would imagine that
the gear-train has been altered from standard.

The lever on the reader has three positions ON, Auto and Released.

 

There is no means provided to switch the unit of, once connected to the
power outlet it is always on, obviously it means that the selector magnet is
always engaged

 

When the printer is energized, it is reset, I.e it runs until the Selector
magnet has been energized and all clutches actuated and the rotor is
positioned on the STOP-bit area.

 

The motor-control board take three signals, one from the Selector amplifier,
One from the On-switch and finally one from the reader.

The motor control board automatically shuts down the motor after approx. 5
minutes, if there is no activity.

 

So, starting I local mode, there is two ways to start up the printer, either
by pushing the ON-button, or inserting a tape in the tape-reader and setting
the reader to ON.

When pushing the ON-button, a pulse is generated (depending how long you
hold the button) the pulse is forwarded to the motorcontrol board connection
2 (MOTOR_ON).

The pulse triggers the timed self-hold made up by transistors T203/T204,
Capacitors C206/C207, resistors R207/P201 and Diode D209. 

The motor will now operate for approximately 5 minutes after the latest
event, ie character printed etc. It is not possible to turn the motor off.

A new 5-minutes delay is generated every time the Selector magnet is
operated, this is controlled by the connection 3 on the motor card.

 

In local mode the reader is started when the Reader Button is depressed
(labelled Leser/Schritt).

The motor is started by the number 12 connection on the motor board.

This seems also been happening if a tape is put into the reader, and that
cannot be correct, and I need to investigate this further.

 

Anyway.

In OnLine-mode, the printer is normally resting, it is actuated with a 24V
signal to the relay on the BS292 card.

This signal starts up the reader, and if a tape is loaded it will read the
whole tape, and the printer will then stop after 5 minutes of inactivity.

When online the printer can be started with the Auto/Man button as well, but
not from the reader switches.

 

Ill hope this makes some sense.

Is there anyone having a similar unit, with the same electronics, please get
in touch with me.

There is still some things I don't understand, and I am not sure if it is
complete, I have referenced the schematic for a Teleprint 390, however thee
is some differences

I am not 100% sure on how the transmit section and receive works, amongst
other things since I have more component, more switches compared to the 390
schematic,

as well as some parts on the 390 schematics is missing in mine.

 

With best regards

Tomas Larsson

Sweden

 

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