[GreenKeys] Searching for Answers.

Sun Jul 18 19:09:58 EDT 2021

Everyone, thanks for all the feedback.  It is very much appreciated that is for sure.  Wasn't sure we would get such a response on a Sunday, but you TTY guys must be just sitting on the ready willing to help out at all times.

UPDATE:
Just placed a temporary jumper from the power switch, on the switched side, directly to the motor contact (#16 on the schematic we’re referring to) on the block under the base behind the keyboard bay.  Flipped the switch to ON and VOILA, THE MOTOR STARTED!

As for a safety cut out to defeat power to motor when typing unit and/or keyboard are removed, none found.  There were two shorting contact sets for shorting the selector magnet circuit when the typing unit is remove to prevent a open loop on the line and the same thing for the removal of the keyboard.

Now to try finding the real problem.  The high impedance scenario seems to be the most obvious.  I would like to keep as much original wiring as possible, but I'm afraid the lacing of the wiring bundle is going to have to be removed to trouble shoot the issue to find the solution.  I used to lace quite a bit 50 years ago and have a good supply of lacing twine on hand, so I should be able to make it look authentic when we are finished.

Steve G./N4TTY

-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of E.
Sent: Sunday, July 18, 2021 5:34 PM
To: Bruce Gentry via GreenKeys <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] Searching for Answers.

Okay, I just briefly reread through this… this morning had too many of the sleepies to do it.  This may not apply but just pulling from memory… you say that you have the typing unit removed and the motor does not run.  Isn’t there a safety contact between the base and and typing unit, so that when the typing unit is removed, the motor stops (saving fingers and the like from being mowed off)?  I could swear there is one there… I think — and I know you mentioned contacts but I don’t have the schematic in front of me… but I think there’s a block of four contacts kind’a in the middle, between the typing unit and the base - and when these are not in contact with each other, the motor stops?  I could swear…..

> -----Original Message-----
> From: Steve Garrison <steve.n4tty at gmail.com>
> To: Greenkeys <greenkeys at mailman.qth.net>
> Sent: Sun, Jul 18, 2021 11:38 am
> Subject: [GreenKeys] Searching for Answers.
> 
> OK, put on your thinking caps!
>  
> Nick, N0NCQ, and I are working on a M15 that will soon find it’s way to a new home in FL with one of our younger members.
>  
> And we have run into issues.  Some of which we seem to have resolved, but at the moment one that stumps us!
>  
> Here is the scenario (once some of the multiple issues were resolved):
> 	• Typing unit and keyboard removed from base.
> 	• M15 plugged in to AC outlet.
> 	• Power switch turned to on position.
> 	• Motor does not start.
> 	• Remove motor from base.
> 	• Measure voltage at motor contacts 13 & 16 on the base and find line voltage of 125V AC (13 & 16 per the schematic we are using).
> 	• Using a cheater cord, apply 125V AC to motor contacts corresponding to 13 &16 (the outer two of the four on the motor unit), motor runs fine.
> 	• With motor back in place on the base, measuring across 13 & 16 from under the keyboard shows a very low voltage.
> 	• With power cord removed from wall outlet and using the cheater cord on the back side of 13 & 16 the motor runs!
> 	• Again using the cheater cord, but now placing the leads on the AC power block at terminals 21 & 23 (with normal power cord unplugged) the motor again does not run!
>  
> Something in the base seems do be the culprit, but there isn’t much else on the base.  Under the base is a mess of laced wiring going I don’t know where.  There is a terminal block in the back left of the base that has nothing connected to the terminals on the top screws of the block.  Guess that was originally where line relay and motor control circuitry was located.
>  
> This machine seems to have some shade tree mechanic work done on it over the decades a we have uncovered and worked around a couple of wiring issues that were done maybe for stop gap measures.  One was wiring the machine in the always on condition as the power switch seemed rather flaky.  This was resolved by just a thorough clean of oil and grease that had accumulated in the switch itself.
>  
> Any and all suggestions accepted!
>  
>  
> Steve G./N4TTY
> Nick/N0NCQ

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