I bought an ARB-704 for my Yaesu FT-991A and Amplifier Ameritron AL-80B. It has the interface cable PNP-8M. The light of the ARB (XMT light) is always on even I did not plug power into the ARB-704. It seems there is a locking PTT button or menu option on the radio that is holding the radio keyed. Any thoughts about what's wrong or what do I need to do to setup the radio menu? Thanks.
I'd ditch the ARB-704 and just connect the AL-80B key line to the rig; the interface unit is not required for this combination and just adds one more thing to possibly fail. AL-80B KEY line center pin to FT-991A TUN/LIN socket pin #2. AL-80B KEY line connector "shell" (of the RCA phono plug) to FT-991A TUN/LIN socket pin #3. Works fine. No risk.
Thanks Steven, It seems I need to do something else to my radio or cable, because the XMT light of the amplifier remains on even when not pushing the PTT. Raul
Pull the phono plug out from the rear of the amplifier. The XMT light should turn off. Now, don't use the ARB-704 at all and just connect the cable directly to your rig as described above. The XMT light should not illuminate. If it does, check the cable with an Ohmmeter for a short circuit, because it will have one. Find out where the short is and eliminate that, and all should be well.
