[GreenKeys] 28ASR with slow release relay in LESU

[John, W9DDD]

My ASR has a slow release relay in it.  It's coil is fired by the space 
contact of the line relay (other stuff in there too depending on the 
position of the K-KT-T switch).

It's an LESU15

https://navy-radio.com/manuals/tty/wd/pc/3298wd-iss12-6402.pdf

Does anyone know exactly how this supposed to work.  It appears to be 
intended to allow you to get local copy during tape punching if there is 
no signal line activity and you're in the K-T position.

So I'd expect to be able to punch tape and get copy on the printer of 
what's being punches with no problem when the Line-Test switch is in 
Test position.  Sometime it works that way and other not.  Sometimes it 
decides it will work with the switch in the Line position and not have a 
line connected.

I'm expecting a dirty contact in either the slow release relay or the 
switch and I'll eventually  go there, but I'd like to have a better 
understanding of what's going on before having the machine torn apart 
for a long period of time.  It'd be nice to figure out how to test it 
before putting keyboard and printer back in.

May I assume contact cleaner works on relay contacts?  I've only used it 
on wafer switches and potentiometers in a previous life. Maybe that 
should be my first approach?  Back to the parts illustrations to see if 
I can get to the needed places with minimal tearing apart of things.


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The above comments or recommendations are SWAG. Use at your own risk.

John, W9DDD