[GreenKeys] Morkrum Model 12 KSR

[Doug Alderdice]

The schematic that Don posted is the same one that I have in an old RTTY 
publication and in some paperwork that came with mine.

D.



On 1/23/2015 11:31 PM, Don Robert House K9TTY wrote:
> 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