[Heathkit] DX-100 mods

[Glen Zook]

The original Heath modification kit which adds the spotting switch and also adds the grid-block keying does not use a diode.  The push button switch is a 2 pole normally open switch.  Somewhere I have the original 4-page instructions for doing this modification.  Several years ago I scanned these sheets and uploaded it to BAMA.  Unfortunately, because the copyrights to the Heath equipment were sold Ken, K4XL, had to remove the Heath information from BAMA.

I will try to find either the scans (I have had at least 2 computers since I scanned the information so they may no longer be found) or the original modification sheets.

There is a little bit more involved than what was described below.  The spotting switch, when the Heath modifications are done, allow the VFO to be "spotted" without activating the transmit switch and whether or not the transmitter is in the AM or CW mode.

I made the spotting switch modification to my original DX-100 back in 1960 and to my "new" DX-100 that I acquired over 10 years ago.

Glen, K9STH

Website:  http://k9sth.com


--- On Sat, 7/25/09, Ron Youvan <ka4inm at tampabay.rr.com> wrote:

Look on the schematic at the line from the key jack to the oscillator and then the subsequent tubes that are keyed, you put a diode between the oscillator and the place where the "key" jack connects, leaving the key connected to everything except the oscillator and possibly the integral buffer.  Then the "spot button" connects directly from the oscillator and possibly the integral buffer to ground.

The diode sets with the arrow pointing to the "key jack." Must I draw you a picture?