Kenwood TK-830 PTT Problem

I have a radio with a good COS that successfully triggers the PTT on two radios I have here. But when I connect it to a Kenwood TK-830 I see a "TX" indicator in the display but no carrier is produced. A Scope across the COS/PTT and GND shows a sharp transition from 5 to 0 volt (as expected) and a residual resistance on the COS line (when low) of about 12 Ohm. To check this R isn't the problem I found I can put as much as 7K in series with the PTT to GND on the TX and get the carrier.



Sort of lost here.

73

BobJ

W4JPA

Kenwood TK-830 PTT Problem