Hi all
I have a very interesting problem with my SB-1000 Heathkit .....This is the
same amp as the ameritron AL80a with a single 3-500z
Hears what happen.... I turn the amp on to use it, Talk on it for a few
minutes, The amp blows the fuse for no reason while in receive... no pops,
cracks, nothing ...just went dead while in standby
I pull the tube test ....still blows fuse.... Test diodes...Check out OK,
but replace them anyway..Still blows fuse...Check caps .....Seem ok... just
for test I leave them out .Still blows fuse with NO caps in amp.... Put it
all back together, disconnect the B+ ....No dice
So I am just about stumped.... I disconnect the HV negative from chassis
....Power it up
It comes on .... Now the power supply is totally isolated from the amp....
As soon as I connected the negative HV from the power supply to chassis
ground it blows the fuse.....
So the only thing I can come up with is the transformer must have some kind
of internal short, Because there is no problem in the diode board or caps &
the power supply will work as long as you do not connect the HV negative to
the chassis
Any ideas .....Richard or Tom ???
thanks john
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