One thing to look for on amps with external anode tubes is a lite coat of dirt
on the tube "seal" providing an arc path between the HV anode (PLATE) and the
chassis / tube socket ground. Used to see it a lot in MLA 2500s.....
Best regards,
Gary - AB9M
CSM(r)G.L.Huber
glhuber@msn.com<mailto:glhuber@msn.com>
www.csm-gh.com<http://www.csm-gh.com/>
9679 Heron Bay Road
Bloomington,IL 61704
(309-662-0604)
National Webmaster for:
The Society of the Fifth Division
www.societyofthefifthdivision.com<http://www.societyofthefifthdivision.com/>
----- Original Message -----
From: Jim Brown<mailto:jim@audiosystemsgroup.com>
To: Ten Tec List<mailto:tentec@contesting.com>
Sent: Wednesday, January 19, 2005 9:25 AM
Subject: [TenTec] Titan 425 Works Fine but Started Blowing Fuses
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
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