Edward Vignati wrote:

Scott thank you , the transmitter is an Elecraft KX3 into a KXPA100, I'm not good with a scope, even though I have one, I will check the resistors, the band switch and grid bypass caps, Thank you very mych

Yeah, but watch the B+ when you key down also. If one or more diodes is
partially failed, you can get into a situation where the supply can deliver
a lot of current from the bypass electrolytic quickly, but after a few seconds
it sags because the electrolytic can't charge up as quickly as it discharges.

Big broadcast transmitters often have neon lamps across all of the diodes
in the series string so that when one goes open or high resistance the lamp
lights up.

If the power drops but the B+ holds more or less steady you can ignore this.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."