[TenTec] Titan 425 Works Fine but Started Blowing Fuses

[Jim Brown]

My vintage 425 just started blowing one of the main 20A fuses for no 
obvious reason. Yesterday, it had been idling (not in transmit mode) 
for at least 10 hours and popped the fuse. I didn't realize what had 
happened until I heard the fan quit.  I didn't have time to check it 
out until last night, when I replaced the fuse and fired it up. No 
obvious problem, and I ran it for a while, then shut it down for the 
night. This morning I fired it up again, called a half dozen CQ's on 
80 at about 1 kW out (roughly 600 mA plate current, low grid 
current) and 1:1 SWR, and it popped the fuse again. 

The tubes are some "pulls" I bought and installed about 3 months 
ago, and seem fine. No audible arcing. 

Any ideas what to look for?  


Jim Brown  K9YC