[HomeBrew] Switching high voltages without a relay?

[John Burch]

Hello Group:

I have a transceiver here that has a bad T/R relay.  

This relay, if the contacts weren't so very badly 
burned due to long and faithful service, would 
apply the bias, and then the screen and plate high 
voltages to the P.A. when the radio was keyed.

As the relay isn't manufactured anymore, I am toying 
with the idea of "keying" these power supply voltages 
with some sort of a solid state device/ transistor/
gizmo.

Would some kind soul with experience doing something 
like this please contact me directly so I can pick your 
brain, and possibly learn from your experiences?

Thanks for the read.

73 de John
..