I recently bought a Flextone III amplifier, and tried to connect to it using Line 6 Monkey through the MIDI port. I was unable to connect to the amp, despite trying all combinations of MIDI IN and MIDI OUT cables. The transmit LED on the MIDI interface flashes but no return data seems to come back, the receive LED never lights. I then tried a completely different MIDI interface through a sound card 15 pin port, to eliminate the MIDI interface, which also failed to connect. I tried a different PC in case there was some bizarre timing issue, same result.

In the splash screen that comes up at the start of Line 6 Edit, under CONNECTING WITH MIDI CABLES it says "be sure your POD /  Amp is set to MIDI channel 1", how do I make sure the amp is on channel 1? I did a factory reset by holding A and D channels simultaneously and turning the amp on, assuming this would reset it, but no change.

All Line 6 software and Java software has just been downloaded, so it is the most recent.

Is there a circuit diagram available for the Flextone III that shows the MIDI input section? I have a background in electronic engineering so I could trace the signals manually.

Any other suggestions would be appreciated. Thanks