by 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