My MARK III isn't working in AM, SSB ok..why?

[ratpatrol]

I just got my Mark III..everything was fine and up and running well...Yesterday, I keyed the mic in the AM mode and the power was going to the antenna, The "on the air" light was lit and people on the on the channel could hear me "key up", but there is no modulation...When I switch to USB or LSB...I have modulation...Its the radio of my dreams and I finally have one. I called a technician who makes house calls on radio equipment coming Monday. are there any suggestions or advice from this forum.? I greatly appreciate it it so much in advance..........JR

[tubefan]

only need to post once. You will get some help from some very smart people. Might take a day or so but you will get an answer. Posting the same question 3 times is like pressing the button on the street lights or elevator over and over again. Only need to press it once and anything after that is doing nothing but exercising your finger

[2600]

Yeah, they call it "cross-posting".

Makes other members "cross".

73