[Boatanchors] Johnson Valiant Question

[Greg Mijal]

Hi:

I've been working on a Johnson Valiant off and on for awhile and saw something that needs your input.
The small interrnal relay pops it's 1.5 amp fuse from time to time. This circuit seems to be part of the PA plate power supply on-off circuit at the primary winding.  After I replace the fuse, things settle down for a time and things seem normal.  Then it happens again.  Over and over.  I noticed tonight that when I go to the transmit mode by flipping the toggle switch,  there is a sudden deflection on the plate ma meter.  Nearly full scale and for less than 1/2 a second.  It blips nearly full scale regardless of what power level I have dialed into the rig and then drops to the level I had previously set.  Another thing is that the plate supply is using 1N2637's solid state diodes instead of 866A's.
My questions are: has anyone seen this one before? Do you think the 1N2637 SSD's may not be such a good idea in the Valiant?
Thanks
Greg
WA7LYO
Kinston NC