I have a Yaesu FT1000-MP connected to an AL-80b connected to an MFJ-989c into a 160 meter loop. I can tune 160, 80, 40, 30, 20, 17, 15 and 10 meters all to almost to a 1:1 swr with the amplifier in standby. With AL-80B in operate I can tune and load the amp good in 160, 80, 40, 30 and 20 meter positions. With the amp in the 17/15 meter position and exciter in transmit I get some grid current and plate current. There is no output and the radio swr meter indicates 3:1 (high swr). I am hoping this is an indication of mistuned input circuit. I've not had a chance to try to tune this. Also with the amp in the AUX position I can tune the load the amp with the radio on 15 meters. I discovered this by accident. In the AUX position I cannot tune 12 or 10 meters. I looked and the 10 meter jumper has been clipped. The 15/17 meter jumpers are intact. I purchased this amp a couple years ago used. I t is physically in excellent condition. I realize that there is no telling what someone may have done to it. I have never switched the band switch while transmitting and the band switch looks good. My questions are: 1: Could the 15/17 meter coil be so mistuned that both ranges look very bad? 2: What should I be seeing, tuning wise, with the 15/17 meter jumpers intact? 3: Should I be able to tune either 15 or 17 meters, but not both unless I cut the jumpers? 4: Is it possible the 10 meter coil can be so mistuned that it I can actually tune the amp to 15 meter frequencies in the AUX position ? I've read numerous threads that pertain to this subject. I'm just seeking more information. It just seems so strange that four positions are working properly and two are that bad. I also want to know what else I could be looking for when I tear into it. I did't notice if the radio's swr meter was reading high when I was trying to tune 12 and 10 meters in the AUX position. I'll check that when I can get back to the shack. Any information and opinions are welcomed and appreciated.