SB220 voltage and tune sparking.

[Jimbo165]

I have 2 SB220 amplifiers. SB220 number one when I put some drive to it every now and then it sparks at tune capacitor. It will make a hum or spark and meter shows 2000 low and 3000 high . It does not spark or hum every time and works great other wise.... Any suggestions to problem????? The other one number 2 with same drive just works like it should but the right hand meter acts up some times and does not show any power on it but amp working. That same meter when it is working show 1850 volt on low and 2400 volt on high. I have not taken it apart to actually check voltage yet. What do i need to look for????? Thanks