[GreenKeys] A few questions.

[Ed Tanton]

Hi Jonathan,

 

Let me try some of these. First, I dislike steel wool around anything
electrical or electronic. Use Scotchbrite/whatever synthetic fiber.

 

Power supplies: the purpose of a loop supply is to provide enough 'stuff' to
actuate the selector magnets while printing. The TU may or may not supply
that power. Mostly, folks refer to that power in terms of current. Usually
either 20mA or 60mA. YOU will likely have to use some sort of resistor to
limit the current those selector magnets 'like'. Be sure to err on the
conservative side. A receiving setup boils down to a TU, a loop supply, and
a machine. To fool around with it, you can simply place the machine's
keyboard in series with the loop supply and use the keyboard to make the
m,achine essentially a typewriter. Makes a good test to be sure all is well.

 

You have to have enough voltage in that loop supply to saturate the selector
magnet coils. I have heard it takes a minimum of 48-60VDC but most folks use
around 120VDC.

 

The idea is that you have some source of audio tones-whether something from
the internet, or a radio receiver. You feed those tones into a TU. Its job
is to convert those tones into switched DC supplied by the loop supply.
Those switched DC pulses work the selector magnets and cause the machine to
print.

 

Sending is sort of the reverse: you tell your TU to create pulsed audio
tones to feed into the transmitter using your keyboard.

 

There is a wonderful array of sights and sounds and smells awaiting you.
There is a rhythm to RTTY. 60wpm RTTY especially. You will learn (maybe
instantly) to love the smell of the electromechanical gears and whatever,
with the oil and maybe a little ozone from the motor. The clanking of the
machine. The paper being struck by the typebars. It's quite a trip.

 

Ed Tanton
 
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From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Jonathan Mc Donald
Sent: Friday, January 06, 2012 1:31 PM
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] A few questions.

 

I have found out that my tt-98 is missing a power supply, but don't really
understand what that means as far as what the machine can and cannot do.  I
read the wiki on loop current, but will have to read it again (and again).
So I'm going to throw some questions out there this morning and head to the
mancave to tinker.

 

Without a power supply:

Will my machine be able to print itty from the internet?

Will I be able to send itty to the internet (i'm not sure my machine can do
this)?

Receive rtty over radio waves?

Send rtty over radio waves (again, not sure my machine can do this, but
suspect it can with a computer and other stuff))?

 

 

 

There is a DC switch on it.  Can I substitute a 12v battery in place of the
power supply?

Would the power supply be an easy or complicated build from scratch?

If anyone has one for sale, I'm listening :)

Can one purchase a newish power supply that would work with it? (a link
would be great for better understanding)?

 

Restoring:  

Is it customary or frowned up to soak the teletype receiving unit parts?

What is the best solution? 

The current plan is oil and fine steel wool.  It seems the least invasive.

 

Yep, all noob question looking for the voice of experience (with surely more
to come).  

Thanks for your time.

Jonathan / kg6tgr

 

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