12 meters not working on my Ameritron Amp.

I have the ameritron al 80a amp and upgraded the choke so it would work on 17 and 12 meters. Works very nicely on 17 now but no go on 12. It will not tune up to much power and you can hear an internal arcing. Every other band works great, including 10 meters. Any idea what might be going on?

Thanks

 

Internal arcing?

Did you try it into a dummy load (and not an antenna)? Does it still arc?

 

Yes sir, this was into a dummy load. I just can't figure why it will not load up if 10 and 15 work ok...

 

What is your input SWR on 21 meters?
You may have to adjust the 10-12 meter input coil..

 

Lack of drive due to input mistuning wouldn't cause anything to arc, though.

Arching is worrisome, since an arc often (and usually) causes damage to something.

 

I missed the arc, I guess that is why I have been treading water for the last seven and a half days.

Sounds like a band switch issue........

 

I just got that!

 

Yeah thats it, band switch. All you have to do is tune 12 Meters in 10 Meter position. If it works it is the band switch