[GreenKeys] 28ASR K-KT-T perf strangeness?

[Nick England]

As usual, after I ask a question I keep digging and find out a little more
info.
The LAK parts book (1169B issue 18, page 26) shows an alternative K-KT-T
cam 176436 with note 1 "Mechanically isolates the Reperforator from the
Keyboard in the KT position". Yep, my cam looks like that.
So far I haven't found anything in a 28ASR or Navy manual that addresses
this variant.
So it seems like what this variant really has is K-K-KT.
(isn't that a song? "ka-ka-ka-Katy")

thinking out loud....
Maybe there is something in the electrical switch assembly that is meant to
electrically disable the reperf selector magnets and/or the keyboard
transmitter, making a difference between K and KT? Nothing shows up on the
Wiring Diagrams I can find, but maybe ohming out the switch will turn up
something.
Maybe there is an adjustment issue to make sure that the keyboard clutch
doesn't get tripped when in T mode? In normal machines, in T mode the
keyboard gets reset by the faster-running perf, allowing you to type much
faster than 60wpm when punching a tape off-line.

It is of course perfectly usable as is, but I always like to at least know
how a machine was originally meant to behave.

Cheers,
Nick England K4NYW
www.navy-radio.com


On Tue, Oct 23, 2018 at 2:52 PM Nick England <navy.radio at gmail.com> wrote:

> I am restoring an AN/UGC-6K (28ASR with aux reperf).
> Strangeness #1
> This 28ASR has an "LTPE1/AWA" keyboard typing perf installed - but it is
> actually a typing reperf with selector.
> I thought LTPE meant typing perf only - this perf/reperf is badged
> LTPE1/AWA and TT-252/UG (the correct military nomenclature for LTPE1/AWA).
> The LTPE1 badge is riveted in place so it probably isn't a case of someone
> switching tags. Did someone once add a selector to an LTPE? That seems like
> a horrible unnecessary job, swapping camshaft, etc. etc. etc. The selector
> wiring goes to a 32-point connector and also an external cable - both are
>
> Strangeness #2
> The keyboard/base says it is an LAK42/ARN
> K and KT mode both mechanically disable the perf - only T mode releases
> the code bar extensions to trip the perf.
> T mode acts like I'd expect KT mode to work - the perf punches AND the
> keyboard transmitter transmits. In a normal 28ASR the T mode means local
> perf only with no transmitter.
>
> So am I dealing with strange out of sync cams on the K-KT-T switch shaft?
> Or are these some weird modes only found on this model?
> The LAK analysis chart doesn't mention anything weird like this for
> LAK42....
>
> As always, any clarification of my poor confused brain is greatly
> appreciated.
>
> Cheers,
> Nick England K4NYW
> www.navy-radio.com
>
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