Hold Function for Radio Shack Frequency Counter (Did It!)

Hold Function for Radio Shack Frequency Counter (Did It!)

Post by Galen Wat » Mon, 15 Nov 1993 02:31:35

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

Ground TP17.  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.

I grounded TP17 directly and the display stopped.  After lifting the ground,
the counter resumed counting at the beginning of a sampling cycle.

Personally, I would ground TP17 thru a 1k resistor.  I haven't performed
the mod to my RS counter, since the pads are VERY small and my fine-tip
iron is at work.  I will try the 1k Hold mod on Monday and give a report
(unless somebody beats me to it).

An amplifier mod to increase the sensitivity is in the works, reports to follow.

Happy Trails to You,
Galen, KF0YJ