[Amps] AL80-A help needed

Jeff Peacock mds at isp.ca
Sat Dec 17 09:03:33 EST 2005


Amp blew a fuse. Discovered that L-401 and D-401 on the capacitor
board were both blown. Checked P/S for shorts and found none.
Replaced the components and fuses but as soon as the AC switch was
turned on fuses blew again as did D-401. Took tube out and tried
again with same results....figure tube is OK. Checked the 12V supply,
caps, etc. but can find nothing odd except the resistance between B-
and chassis ground (about 2 ohms).

Something is pulling a lot of current and blowing that diode and the
fuses. With no short in the P/S, I can't figure out what is going on.
The transformer primary measured resistance checks out with what
Ameritron lists for that transformer (about 1 ohm +/-).

Can anyone point me in the right direction here?

Jeff
VA3XQ


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