[GreenKeys] Help with an M15 restoration

[gil smith]

Hi folks:

I am putting an old crusty M15 back into service for someone, and need some 
help.

This thing was pretty dirty.  After reading some of your cleaning stories 
last month, I opted for a twist:  I took it to a car wash.  I used the 
engine-cleaning spray, then the soapy spray, and finally gave it a good 
rinse.  Turned out great!  A few hours in the Arizona sun dried it off 
nicely.

Then I oiled everything -- every linkage, gear....  Many parts were frozen, 
or nearly so, but with the exception of the keyboard encoder, everything 
loosened up nicely with some oil and movement.  I oiled the cups, soaked 
the felts, greased the cams, lubed the motor bearings, and was eventually 
able to get the mainshaft turning by hand.

I traced out the wiring, bypassed the polar relay stuff and all the RF 
filter gizmos, to bring out just the isolated selmags and kb contacts on 
the terminal strip.  Powered up the motor by itself, which ran nice and 
quiet.  So far so good.

Put the typing unit back on the base and fired it up.  Everything rotated 
properly in the open-loop state, with the exception of the gear shaft that 
drives the motion of the carriage.  In my other (working) M15, in an open 
loop state there is no rotation of this vertical carriage-drive 
shaft.  There must be some clutch in the mainshaft that lets the drive gear 
freewheel, but I don't see where it is or how it is 
activated.  Unfortunately, that shaft did not freewheel in the new M15, and 
it stripped teeth off of the fiber gear on the vertical carriage-drive shaft.

So now I need to figure out how to loosen the carriage-drive clutch, 
wherever it is, and replace this fiber gear.  But the rest of the typing 
unit looks to be working well, though I have not tried to drive it from a 
loop yet.  And I need to free up the encoding arms in the keyboard.  A few 
questions:

- anyone have advice on freeing the clutch?
- anyone have a gear for the carriage-drive shaft (the large fiber one that 
is driven from the mainshaft)?
- anyone have advice on how to change said gear?

Actually, if someone has a spare typing unit for parts, that would be good 
too.  I am also missing a few keycaps (LTRS, LINEFEED, BLANK) if anyone has 
a stash, and need glass for two M15 cabinets.

Has anyone ever had a glass shop cut and bevel glass for a machine?

Any input appreciated,

thanks,

gil





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