Hi Alan & LF,

You (Alan G3NYK) wrote :-

"It might be worth sticking a big 50 volt zener across the power unit
to clip any transients."

That sounds worth a try.

And

"What sort of PSU is it ??"

It is a simple affair using a big toriod transformer, 40V x 40V at 6.3A
500VA with windings in parallel smoothed by 2 x 10,000MFD 100V capacitors
(voltage is about 45V before going to transmit state) & a smaller toroid to
supply about 28V DC to 24V & 12V 3 leg IC regulators within the transmitter.

I am only using the variac at present because I wanted to bring it up gently
until I was sure that all is well, I will need to fit some sort of soft
start when I am happy with it & know I can run it at max volts, I can then
remove the variac.

Thanks for your feedback.

Regards,

Gary - G4WGT - IO83qp

Web : http://myweb.tiscali.co.uk/wgtaylor