how to connect T1000Z to demodulator for RTTY

Fred55 · #1

I have almost finished restoring my T1000Z - took me 4 months
I took it completely apart(not the printer). I changed all the electrolytics and tantalum caps, except for the 2 large electrolytic caps in the power supply sitting in those black plastic cylinders.
I have it working on local loop, but it is doing strange things.
If I try to type on the keyboard and punch a tape, it works for anywhere from 2 characters to half a line, but then it stops punching and go into a hold mode. I then have to press the "I" button to activate the keyboard again.
How can I prevent this from happening ?

Next problem - how do I connect it to a demodulator ? There was a sticker on the case that said 60vdc and 40 mA.
Is there a power supply inside that has this voltage ? There must be something, because it works on local mode.
There is a cable that comes out and it has multiple colored wires. The 1/4" plug was ripped off accidentally,
so I don't know how to hook it up to a demodulator. Do I need a separate power supply for this ? Or does it work by polar relays ?
I have no idea how to connect this to my dovetron terminal unit, or my HAL ST-6000
The cable has wires with the following wires:
red
blue
orange
grey
white - this was connected somehow to the jack
green - this was connected somehow to the jack
yellow - this was connected to the brown wire, and was connected somehow to the jack going to the demodulator
brown - this was connected to the yellow wire, and was connected somehow to the jack going to the demodulator

Need help please !
I have worked so hard on this unit to get it to this point. It would be shame if I could not get it to work for my amateur radio station
Thanks, Fred
VE3WN / VE3PIE

#2

Fred,

The T1000z is almost certainly standard in the connector wiring.

Forget the Red, Blue. Orange and Gray wires for now

White and Brown are for the Transmitter (Keyboard)

Green and Yellow for the Receiver ("Electromagnet")

Without seeing the LAT board in your machine I cannot tell you if it is Single Current (Neutral) or Double Current (Polar)

Hopefully it is Single Current with "TW39" LAT - in that case, it is easy to connect to the Dovetron - you need to connect the Brown and Green wires together, then use White and Yellow to connect to the Dovetron Loop connector - back the loop current control off completely - American loop voltage is quite high in comparison to German standards - once all is connected,advance loop current when receiving a valid signal and see if the printer starts - if not or if it prints rubbish, reverse the connections to the loop. If you are really keen you want to aim for 40ma loop current.

#3

With regards to the printing stopping halfway across a line - Check the microswitches on the printer - there are some that send the control board information regarding the end of line - if these are defective, or wrongly positioned, then this problem happens

Fred55 · #4

will the "north american" higher voltages damage the magnets or the electronic circuit components ?
should the voltage be reduced ? and if yes, how should I do this ?

Thanks, Fred

#5

Hi Fred,

No, I think you will be fine - need to be certain that your machine is for TW39 operation. I think from the description of the original connections this is most likely.

The open circuit voltage of the Dovetron will be around 110V, this will drop greatly once loaded by some loop current - I-Telex sits around 80V open circuit.

You may find that some extra series resistance is needed to get the loop current down, but you will find out from testing.

#6

As far as I remember has the Dovetron line voltage around 160 volts. But no worries. The line circuits of the T1000
are proofed for 2kV! minimum. Important is line current of 40ma.

Fred55 · #7

the DF3OE teleprinter museum is unresponsive
is it non-functional ?
Fred

Fred55 · #8

W2HX helped me with some information on getting the unit to work with 45.45 baud.
There is a DIP oscillator crystal on the front PCB upper left. If we change this to a different frequency then we can copy 45.45 baud

I believe the crystal frequency should be 2.61792 MHz
Will this work ?

Ideally I would want to copy 45.45 baud (60 wpm) and 100 wpm
If I change the crystal so it works for 60 wpm, how will this affect the speed switch on the T-1000 ?
In a perfect world I would set the switch to 50 wpm and it would actually copy 60 wpm, and then if I set the switch to to 100 wpm it would copy 100 wpm.
If that does not work for both speeds I could wire up a small switch with relays to switch between the 2 chips

the part number at the Digikey supplier is:
https://www.digikey.com/en/products/det ... -AN/502317

They program the frequency

Please give your expert advice

Thanks Fred
VE3WN