Concept:  Modify a 10V/Control Module by adding a PTT disable switch in place of the intercom switch.

Description:  A technician may want to instantly disable the transmitter to check for desense.  This modification replaces the "Intercom" momentary slide switch with a two position slide switch to allow disabling of the PTT.

Switch Installation Procedure:
1. Completely remove the intercom switch from the 10V regulator card. This is accomplished by removing the two phillips head screws, accociated nuts and lock washers. Save the hardware, you will need it to mount the new switch.
2. Obtain a similar looking SPST slide switch from a convenient source. Radio Shack sells a pack of 2 such switches for a few dollars. The RS part number is 275-401.
3. Mount the new switch where the intercom switch was removed. Be sure the switch is on when the slider is in the up position.
4. Solder two pieces of scrap wire (approx. 5" long) to each of the two terminals of the switch.
5. If there is a jumper from hole 1 to hole 2 on the circuit board, remove it and clean the solder out of both holes.
6. Solder the ends of the wires into these two holes. It does not matter which wire goes in which hole.
7. Re-label the intercom switch to indicate "PTT Disable."

Notes: The action of the PTT LED will still indicate when the station is keyed (On Air Lamp). If the disable switch is in the down (disabled) position the station will not key from any source. The PTT switch will still work as original.
 
 

This modification was prepared by M. Scott Zimmerman  N3XCC, Jan 29, 2004
Comments welcome, email Scott
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