RASCAL to TS-450 Help

Discussion in 'Working Different Modes' started by N3HGB, Oct 22, 2019.

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  1. N3HGB

    N3HGB Ham Member QRZ Page

    I have an old Buxcom Rascal and recently upgraded from a TS-440 to a TS-450. The RASCAL does not work on the 450, connecting it locks the radio in receive only mode. Just connecting the 13 pin DIN cable locks it too, it doesn't even have to be connected to the RASCAL to have this effect.
    Step 1 is I got a new 13 pin DIN cable and plugged it in the radio. No effect, so the issue was definitely in the old cable.
    Here is how the RASCAL is wired:
    Here is a comparison of the 440 and 450 connections to the 13 pin DIN:

    What I think happened is pin 9 is wired to ground on the old cable. When you plug it into the 440 the microphone no longer works. This was probably to keep ambient noise out of the signal. On the 450 pin 9 does that and keys the radio to transmit. Kenwoods have an oddity where if you turn them on with the transmitter already keyed, they refuse to transmit. I also think the RASCAL schematic is wrong and they also must be triggering 13 to actually transmit.
    So my question is, how to wire my new cable????
    Clearly I don't want 9 permanently grounded. What I *think* I see is the audio in and out remain the same. I can either ground 9 to transmit and mute the mic or ground 13 to transmit and not mute the mic.
    Does anyone see any harm in plugging in and grounding 9 and then 13 to test and see what happens?
    I also noted the 440 wants 500 mV audio and the 450 wants 20 mV audio. There is a pot I can set on the RASCAL for transmit audio, I assume I'll need to set that lower.
    Any advice appreciated - 73 de N3HGB

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