Fixing Stuff: A TenTec 645 CW Keyer

Figure 1: The ball bearing assembly, extracted from the old keyer

The old TenTec Ultramatic Keyer is still used today by many amateurs, including myself. Its Ultramatic keyer mode was born in 1953, and later overtaken by the Iambic A and B modes. I still use the two of these keyers that I own, but one recently needed a repair … In the video shown in figure 2, you can watch a 35 second walk-thru of the disassembly and repair.

Read more about fixing the old 645 Keyer …


3 thoughts on “Fixing Stuff: A TenTec 645 CW Keyer

  1. Hi Ron,
    My question for you is, how does the Ten-Tec 645 keyer operate? Is is iambic, ultimatic, or some other non-iambic mode? Also, are there mode switches on the back panel?

    Thanks Ron

    Brian Kelley – NM7T


    • Hi Brian, Well I think it supports only the ultimatic mode, but in practice I don’t notice much difference when using my other (iambic mode) keyer. The back panel has fixed vs auto weighting, and a weighting pot. Also, there’s a dit memory (on/off), and a dah memory (on/off). Hope that helps,
      – Ron


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