John,

Thanks! that could be the explanation. I see on the parts list different p/n for the cams for single and two cycle operation. But not very obvious just looking at the reperf.  I would think that there would be a reference to LRPE2 somewhere that it is two cycle and will therefor give you twice the speed you would normally have.

I'm not very familiar with the workings of the M28 line. The ones I've had just worked and I didn't have to do anything to them.  I'm more familiar with the M15 and Kleinschmidt machines. (KLI machines always had two cycle selectors.)

Thanks for the pointer to Bul 255B. That talks a little about the 1 and 2 cycle units. But doesn't tell how to identify them or mention LRPE2. It implies Fig 1-4 & 1-5 show the two units. But they are different views and both are labeled "Two-Cycle"!


Tom -  I'll check the clutch when I'm at the Museum next Tuesday.  do you have a source for 200wpm signals?

Thanks,

Duncan


On 01-Dec-21 10:20, John W9DDD wrote:
Perhaps it has 2 cycle cams? So it processes two characters per omemraotation of the shaft,  check the parts section.

See page 4 of https://www.navy-radio.com/manuals/tty/jh/ttyman7/TeletypeManuals/model28/573-119-800TC-Iss1.pdf

John, W9DDD


On Dec 1, 2021, at 4:43 AM, Duncan Brown <[email protected]> wrote:


I am working on a Teletype Corp M28 RT (thanks Bill!). After cleaning it up and lubricating it, I put a signal to the LRPE2 (non-printing reperf) yesterday, but it is just punching garble. All the punch pins are punching and the punch patterns are repeatable, so I don't think anything is sticking.  Adjusting the Range control makes some difference in the punches, but still garble.

The fixed receive bracket gears in the LRXB base are what is called for in the manual (fig 3) for 100wpm ("A" gear =158700; "B" gear = 158716).

But when I give it 100wpm characters (from a M28 KSR or Heavy Metal), the reperf acts like it is running much faster. For example, if I send LTRS, it punches 01111, which implies that the reperf is looking for the first data bit while it is still receiving the start bit.

If I send Blank, it punches 00000 00001 (punches two characters), implying that the reperf is reading two bits for every one that I send.

I know that the cross-office lines in the auto switching centers operated very fast - up to 1000wpm.  Is this LRPE2 running at 200wpm?  I can't find anything defining a "LRPE2", other than "non-typing reperf"

Thanks,

Duncan
K2OEQ






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