[GreenKeys] Morkrum Model 12 KSR

[Don Robert House K9TTY]

I sent scans of the complete Model 12 P Practices with wiring diagrams to Nick England and he put it on his website.
I also have the Morkrum letter size practice for the M12.  I do not remember if I sent that to Nick as well but can send it to anyone who might need it.
I keep the original M12 P Practice in its original leather binding next to my bed.  I read it when I have trouble falling asleep.
Too bad no one thought of doing an exploded parts diagram of any of the M12 assemblies.

Don
K9TTY

Attached is the schematic


On 23 Jan 2015, at 8:44 PM, Duncan Brown wrote:

> Doug,
> 
> The basic schematic of the M12 is in Kretzman's "New RTTY Handbook", along with the modifications for the keyer.   If you don't have it, I can scan it for you.
> 
> The Museum has some extra M12 keyboards.  They are series-governed motors (more noise!) and are dirty, but you can have one if you need to replace your present unit.
> 
> Yes, i would like to see some pictures & dimensions of the cover. maybe we can get someone to fabricate one.
> 
> 73,
> 
> Duncan
> 
> 
> 
> On 23-Jan-15 21:19, Doug Alderdice wrote:
>> My M12, sadly, is not running.  The individual components are functional, i.e. I can power up the motors on the keyboard and the printer and they run and they are mechanically complete, but the machine as a whole does not run.  I acquired my machine in the early 90s from an older local ham when he was downsizing and he had completely rewired the machine to work with a tube keyer to minimize the RFI when using it on the air.  The keyer was not operating, there were no schematics, etc. He had completely rewired the table to work with the keyer ... and had done things like wire the power leads to the printer and keyboard motors with 20 AWG wire!!
>> 
>> I removed all of his wiring and have tried to get it back to original, yet all I get on the machine are random characters.  The keyboard works as I can drop it into the local loop here and can type on it just fine to the other machines in the collection.
>> 
>> I am fighting a number of variables: the condition of the contacts on the table and the keyboard and printer, the contact block on the table is cracked and needs to be glued or epoxied back together, and the keyboard itself has been completely rewired at one time and the last time I spent some time with the project I had come to the conclusion that contact wiring on the keyboard doesn't match a schematic that I have for the M12 keyboard.
>> 
>> When I first got the machine I set it up on the kitchen table one evening and hooked it up with every clip lead I own and managed to be able to type on the keyboard and have it print on the printer. I recall that I couldn't type at full speed on the keyboard and have the printer follow accurately and all of the machinery made a tremendous racket, as well as the electrical part of it creating a ton of RFI.  So I know it *should* work, but that table wiring is proving to be elusive for something that should be relatively simple.  And of course there is never enough time for all of the projects.
>> 
>> I do have the cover for the machine.  I will try to get some photos and measurements of it.  I believe Don needs that information as well and I think I promised him that a long time ago :redface:
>> 
>> I haven't been to the AWA museum yet.  It's been a "gee, we should do that sometime" item for a local ham radio buddy and me for some time now, but we haven't managed to do it.
>> 
>> Oh, and yes, you do need a separate DC supply to run the selector magnets in the printer.
>> 
>> 73,
>> 
>> Doug, KA2WFT
> 
> 
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