[GreenKeys] M19 perforator punch question

[eric]

For what it's worth, at one point (i can't even remember why) I tried 
driving my M19 punch with a current-limited power supply and kept 
turning up the current until it started working, it looked like it 
required about 500-600 mA to punch reliably (at 120VDC).

On 2023-09-24 09:19, Nick England wrote:

> Thanks, Eric - and thanks to all who have responded with helpful info 
> and links to manuals.
> One of the reasons for the session yesterday was for me to deliver a 
> 120vdc 1a supply to provide enough oomph for the punch.
> 
> I understand a more about the punch activation now - Note 13 on the 
> P90.954 WD that you sent is a good explanation - The M19 K/KT/T works 
> essentially like the 28ASR with which I am familiar, the main 
> difference being that the M19 punch is powered by electromagnet and the 
> M28 punch is powered by the motor shaft.
> K mode - no punching
> KT mode - Cam Pulsing Contacts on the keyboard drive shaft pulse the 
> punch magnet
> T mode - the U-Bar Contacts pulse the punch magnet (meaning punching is 
> not restricted to machine speed as Eric V. pointed out)
> 
> Cheers,
> 
> Nick England K4NYW
> www.navy-radio.com [1]
> 
> On Sat, Sep 23, 2023 at 10:19 PM E. <hanyou at xsmail.com> wrote:
> 
>> Being a 15/19 guy...
>> 
>> 1 -- the perforator is not powered by the loop - instead, it is 
>> powered by what would have been the 120VDC rectifier on the backside 
>> of the 19 table (takes a lot of amps to punch - a 1A rectifier is 
>> usually good).  You can test it by removing the keyboard and 
>> connecting alligator clip test leads from the rectifier, to the 
>> correct terminals on the keyboard (and of course with the correct 
>> polarity)... but be careful 'cause that is a lot of juice to 
>> accidentally bump.
>> 
>> The switch on the TT - as mentioned before, powers the punch with the 
>> switch is down, turns it off when the switch is all the way up or 
>> allows you to see what you are punching on the printer, when set in 
>> the middle.  The AC power switch does not need to be on when it's only 
>> set to punch (but on for the rest preferably).
>> 
>> 2 -- When you press a key, there is a bar that slides underneath the 
>> keyboard, to the punch - and that allows the punch to select the 
>> proper Baudot code to punch... no cam shaft needed.
>> 
>> 3 -- Attached - the best diagram you may find, but mileage will vary 
>> :) .
>> 
>>> On Sep 23, 2023, at 4:32 PM, Nick England <navy.radio at gmail.com> 
>>> wrote:
>>> 
>>> I tried to help out a fellow with a M19 today - and I know nothing 
>>> about that era equipment - first time I had touched one. So no 
>>> surprise that I wasn't too helpful figuring out where a stray wire 
>>> was supposed to go.
>>> 
>>> Symptom - This punch magnet is always on in T and KT, off in K.
>>> 
>>> Question 1 - can you remove and standalone test just the 
>>> keyboard/perf assembly with 120vdc (obviously having to rotate the 
>>> driveshaft by hand).
>>> 
>>> Question 2 - is the punch magnet supposed to only get activated by 
>>> the closure of the cam contact on the keyboard shaft? Or is it one of 
>>> those oddball things that is always on except to punch via spring 
>>> power?
>>> 
>>> Question 3 - is there a good simplified WD for a dummy like me?
>>> 
>>> Thanks,
>>> Nick the M28 guy
>> ______________________________________________________________
> 
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