[GreenKeys] Kleinschmidt TT-4A UPDATE

[Duncan Brown]

Greg,

Your TT-4Cs look very nice!!  Looks like they have plenty of grease, 
from what I could see.  One of the first things I do when I get a 
Kleinschmidt machine besides checking for grease is to check all the 
felts.  They should be saturated with light machine oil.  Also the clutches.

Manuals for US Army radio teletype equipment of the 1960s can be found 
at WWW.RATTRIG.com.  The manual sent to you was a "-12" manual which is 
1st & 2nd echelon mantenance which is basic operation, changing fuses & 
lamps and  setup.  The service manual will be the same number, but end 
in "-35" (3rd -5th echelon maintenance). It will give all the 
adjustments & lubrication information.

One thing to watch out for is that the unit has a big radio-interference 
filter and the chassis needs to be grounded (that is what the braided 
wire hanging off the power connector is for). Make sure you connect that 
up, or the chassis will be hot from leakage in the filter capacitors. (I 
got zapped good a couple of times in Viet Nam trying to remove a unit 
from a metal rack when someone hadn't bothered to put the ground strap 
back on.  I learned quickly to always unplug the unit before moving the it!)

There should be a tuning fork attached to the cover door.  this is for 
setting the motor speed - see manual.

You will need a loop supply of about 100-150 VDC (120 V nominal, but it 
is not critical).  You will probably want to run a 20ma loop - that is 
with the switch on the left side in the "VF" position.  (You can use 60 
ma, "DC" position, but you will need a bigger loop supply.)

For a signal source, ITTY is probably best - see RTTY.com.  But ITTY 
provides an audio signal and you will need a "modem" of some sort to 
change it to the required 20 ma DC.  Try to find an old (from 1950-1980) 
amateur "Terminal Unit" or military FSK converter. These generally have 
the loop supply built in.

Another signal source is "Heavy Metal" 
http://www.albinarrate.com/index.php?option=com_content&view=article&id=51:heavymetal 
   This  is a computer program that will go out onto the Internet, bring 
back text files (news, weather, etc), convert it to 5 level TTY code and 
send it out the serial port of your computer.  Then all you need an 
adapter/level shifter to convert the computer's serial data levels to 
your 120V, 20 ma loop.  There are commercial adapters around, or you can 
make one simply with an optocoupler.  The adapter  or optocoupler will 
then key your loop.

Have fun,

Duncan