[GreenKeys] Model 15 troubleshooting

[Ralph Mowery]

----- Original Message ----- 
From: "John Nagle" <nagle at animats.com>
To: <greenkeys at mailman.qth.net>
Sent: Friday, January 30, 2009 2:45 PM
Subject: [GreenKeys] Model 15 troubleshooting


>    OK, I have my model 15 oiled, powered, and connected with
> keyboard and printer in series.  It runs, but won't type correctly.
> Not even close.
>
>    First, this is a "clean" model 15; there's no sign of damage
> or nonstandard modifications.  It was just in storage for a long
> time, and the lubricants had gunked up.  I've cleaned it by
> immersion in Simple Green, and oiled it per the manual, using
> 5W-20 Valvoline synthetic, with lithium grease on the gears and
> big sliding parts.  Small oiling points were oiled with a one-drop
> precision oiler.  Everything runs, and reasonably quietly.
>
>    Loop power is 120VDC regulated, through a resistor just under 2K.
> The selector magnet has a 55 ohm resistance, and loop current was
> measured at 60.4 mA.  The selector magnet ("pulling" type)
> seems to be pulling in correctly.
>
>    But the selector magnet seems to be "slow", like it can't keep
> up with the incoming bit stream.  RYRYRY doesn't bring up alternating
> code bars.  It's as if the selector magnet can only keep up with
> about half the bit rate.  (The machine seems to be running at standard
> speed; it's not like somebody put in 100WPM gears or something.)
>
>    The selector magnet faces are clean of oil, the selector magnet
> moves freely, and all the obvious stuff seems OK.  The swords
> and everything downstream from there seems fine.   I've de-gunked
> and carefully oiled everything in that area, and it doesn't help.
> Adjusting the range finder has little effect.
>
>    Am I missing anything obvious?
>
> John Nagle
> _______________________________________________

One more obvious thing.  Are the coils in parallel and are the windings 
phased correctly ?.  I don't recall the resistance with out looking it up. 
It is possiable to phase them wrong (just reverse the wires on one of the 
coils) and the magnet is too weak to work correctly.