Please refer to the following: http://www.repeater-builder.com/midland/midland-13-513-owners-manual.pdf
On the AF board locate Q202. Right next to it there is a yellow wire going over to Q204. You may either connect to the yellow wire or the collector of Q202. This signal is almost non-existant and if it is weighted down too much the squelch gate will no longer function and audio will not be heard from the radio. A high gain transistor is recommended as a buffer, preferably a Darlington transistor such as the MPS-A13 with a 2.2K - 10K resistor on the base. A FET such as the 2N7000 might also work. If no such transistor is available, a standard NPN such as the 2N3904 may be used as the buffer, but the value R222 will have to be changed to 330 - 1K depending on the resistor that is in the base of the NPN you just added. A small amount noise may also begin to leak if R222 is made too low.
