Well, the saga continues. I now have a brand - new power supply capacitor
bank in my Gonset 903a 2m amplifier. I needed to replace the socket in the
unit a long time ago because the built-in cap was shot. Now, I think I may
be down to the final component that needs to be replaced...
...When I replaced the socket for the 4X150, I couldn't find a SK-600
socket - which would be the same in the amplifier. I opted for the SK-620
which I was told would be a better choice due to improved design. Now I am
not sure of this, but it seems that there is a MAJOR difference between the
2 as far as cooling goes. The 4X150 needs forced air cooling, and the
chassis under the tube in this amp is pressurized when the squirrel cage fan
is on. If the tube is not in the socket, there's TON's of air that comes out
the socket. However, with the tube in, the air escapes out the tube, but
I've also got some air that comes out the inlet side of the fan! So it
appears to me that the socket may not have enough open area to let the air
pass through to the tube. What I wanted to try is a stronger fan to see if
this will make a difference, since the "cage" in the fan is a bit old. The
reason for all of this trouble is that the amp shuts down after a few
seconds of transmitting when the tube gets too hot. If I let it cool for 2
minutes, the amp works fine again, until it heats up. I've also tried
different tubes with the same results. Should I replace the socket - even
though the SK-620 is designed for this tube (but not the original in the
amp)? If you think it's the fan, where can I get a stronger blower for this
amp with an output dimension of roughly 1 1/4" by 1 1/2" and runs on 110V? I
really appreciate the help you guys give to us novice amp "people"!
...Larry
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