[GreenKeys] AN/UGC-143A teleprinter info/parts wanted - long shot

Nick England navy.radio at gmail.com
Sun Apr 20 14:23:40 EDT 2025


The keyboard is attached via a DB37 (no documentation on what signal/power
is on there)
http://www.navy-radio.com/tty/ugc143/IMG_1452.JPG

The keyboard processor board has two 5v regulators on it and its logic
chips seem to have +5 OK - I was hoping to find just a shorted tantalum
killing a power rail, but no such easy problem! (and the damn thing is
conformal coated so a pain to make measurements.)
http://www.navy-radio.com/tty/ugc143/IMG_1460.JPG

It looks like the keyboard itself and the fluorescent character display are
standard commercial parts - they are connected to the processor board via
ribbon cables
http://www.navy-radio.com/tty/ugc143/IMG_1461.JPG

Access is via the bottom of the keyboard so it is pretty awkward - I may
make an extender cable so I can more easily probe things.
First I will look at the Z80 to see if it active (I think it must be
because during power-on the character display gets initialized and then it
says "PLEASE WAIT". Then the printer finishes its power-on sequence and
prints "READY", but the BIT status code says "keyboard not installed",
http://www.navy-radio.com/tty/ugc143/IMG_1463.JPG
http://www.navy-radio.com/tty/ugc143/IMG_1465.JPG

Then I will look at the TX and RX lines on the keyboard USART that talk to
a USART in the control unit.
There must be some attempted handshake during power-up BIT because the BIT
status at that point says "keyboard not installed". And thereafter the
internal software thinks this is an RO with no keyboard.....

But I got no flow diagram or much about how the controller, keyboard, and
printer microprocessors actually interact, other than that they use serial
links.
http://www.navy-radio.com/tty/ugc143/message-generation-01.jpg

-----------------
Keyboard unit A3
applies serial data directly to backplane interface A2A1A3A1, backplane
A2A1A1, I/O connector assembly
A2A1A2 and I/O connector assembly A1A4 to the receiver section of a USART
on port card A1A2A1 of electronic
control unit A1. The electronic control unit A1 USART converts the data
back to parallel form for processing
by the IOC microprocessor and storage in the dual port RAM of DSC A1A2A3.
Based upon receipt of
KYBD ONLINE data in the dual port RAM, the storage control functional group
( paragraph 3-4) develops
appropriate control signals. Control signals are sent back to keyboard unit
A3 by reversing the path followed by
the KYBD ONLINE data except for the substitution of USART transmitter
section for receiver sections and
receiver sections for transmitter sections. Character keys typed by the
operator, thereafter, follow the same path
as the KYBD ONLINE data to be stored in the DSC dual port RAM. The control
microprocessor on the DSC
(figure FO-5-3) transfers data in the DSC dual port RAM into the print and
communications lists of the buffer
memory. From that point keyboard originated characters are transferred to
the print and transmit buffers in the
dual port RAM for routing to the message print and message transmit
function circuits.
------------------

Nick England K4NYW
www.navy-radio.com


On Sun, Apr 20, 2025 at 12:44 PM Jeffrey Golas <jeffg at junknet.net> wrote:

> Id start by seeing if the keyboard port has any dc rails to it. Is it a
> db9?
>
> Jeff
>
> On Apr 20, 2025, at 11:45 AM, Nick England <navy.radio at gmail.com> wrote:
>
> 
> That “180 lbs” may be an OCR mistake for “130 lbs”.
>
> For the ASR version which I have, the control unit is 28 lbs, the printer
> 61, the keyboard 11, and the mag tape 32 - so I hauled it from the garage
> downstairs to my workbench one piece at a time. I don't have the mag tape
> unit, which might be fun, but you can also edit and store messages via a
> paper tape I/O port. If I can't figure out the keyboard, I suppose it will
> just be a printer. At the least it is yet another interesting project.
>
>
> Nick England K4NYW
> www.navy-radio.com
>
>
> On Sun, Apr 20, 2025 at 10:43 AM Jeffrey Golas <jeffg at junknet.net> wrote:
>
>> I have a bunch of UGC-74s and at 100lbs their definition of portable was
>> pushing it already.
>>
>> Jeff
>>
>> On Apr 19, 2025, at 7:17 PM, Duncan Brown <duncanancy at earthlink.net>
>> wrote:
>>
>>  At 180 pounds (!), it is what the Navy would consider "portable"
>> ("anything that can be carried on a battleship").
>>
>> The UGC-143 looks similar to the Space Shuttle teleprinter Curious Mark
>> did a series on a few months ago -
>> https://www.youtube.com/watch?v=7HihKMIVnbs
>> Initially, he refers  to it as a "Navy teletype", but later shows
>> pictures of the AN/UGC-74 (which was more Army & Marine Corps)
>>
>> A block diagram of the UGC-74 & UGC-143 would probably be pretty similar,
>> but was there any connection between the two?  Or just two different
>> manufacturers trying to solve the same problem?
>>
>> Have fun,
>>
>> Duncan,
>> K2OEQ
>>
>>
>> On 4/19/2025 2:33 PM, Nick England wrote:
>>
>> This is a circa 1988 machine I am trying to revive with not enough
>> technical info. To my surprise the control unit and the printer appear to
>> work - but not the keyboard.
>> A description and photos of the beast are at
>> http://www.navy-radio.com/tty/ugc143a.htm
>>
>> It, of course, uses multiple microprocessors - It will pass BIT
>> diagnostics except that evidently the printer Z80 isn't talking to the
>> keyboard Z80 so it doesn't think that the keyboard is actually plugged in.
>> I believe that the keyboard Z80 is alive because the one-line display on
>> the keyboard says PLEASE WAIT.
>> I have an operation and troubleshooting manual which covers the built-in
>> test routines, but that stops at the "replace the keyboard assembly" stage.
>>
>> So does anyone have a spare keyboard or a tech manual with schematics
>> that I could borrow?
>> This is a very long shot, but you never know what someone has accumulated.
>>
>> Cheers,
>> Nick England K4NYW
>> www.navy-radio.com
>>
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