[TenTec] Model 315 Receiver

[Byron Tatum]

Hello-   I recently went through a model 315 receiver and have it working well. I wonder if anyone has experimented with the AGC and with making the S-Meter a little more responsive? The S-Meter is reading the difference between the +12.0 VDC rail (coming off of meter zeroing pot) and the "R" voltage. As signal strength increases the AGC voltage gets more positive and in turn reduces the "R" voltage through action of complementary transistors on control board.  According to the manual the AGC voltage doubler develops maximum of about +2.5 vdc. I injected +3.1 VDC into the AGC terminal on control board and the "R" voltage was reduced to 5.5 VDC. The S-Meter read S-9. The very strongest signal I can find, from a very good antenna, drives the S-Meter to only S-7 at very most and I see around 2.0 VDC AGC voltage developed.   I believe the AGC voltage doubler needs to develop a little more voltage for a given signal strength as I have some slight but noticeable distortion only on the strong signals. I would assume one would need to drive the AGC emitter follower stage a little harder, to inturn drive the voltage doubler just a little harder to develop a higher AGC voltage.   I may try experimenting with the 15K series resistor to S-Meter (coming off of S-Meter zero pot) to make it respond more to the voltages it is measuring between zero pot coming off +12 VDC rail and "R" voltage terminal.   Just looking for someone else who has experience with model 315.Byron W5FH