Red Wave Radio

How to add a hold function to the Radio Shack RF Frequency Counter:

Ground TP 17.  In the schematic, TP17 is pin one of U3, connected to
+5V thru a 47k resistor.  On the circuit board, TP17 is on the display
side, just right of the lower-right corner of the IC.  Grounds are about
1/4 inch below and to the right, the three non-tinned points in the large
area of metal.  TP17 is the tinned pad next to a SM resistor marked '473'
for 47k.

I rigged a momentary switch to ground TP17 thru a 1k resistor (you never
can tell) and it works just fine!  I drilled a small hole to mount the switch
just above the plastic depression so I could push the button with my right
thumb.  A small toggle switch would fit.

I'll be trying the other TP's to see what wonderful things RS didn't put
on the front.

Galen, KF0YJ