[Amps] Problem with SB-1000 Power Supply

[Lane Zeitler]

Mark olson, KE9PQ, from time to time, offers OEM replacement xmfrs for the 
SB-1000 on ebay. He also has a nice online store with lots of amp parts.

Lane
Ku7i


>From: "John" <hydro@naturecoast.net>
>To: <amps@contesting.com>
>Subject: [Amps] Problem with SB-1000 Power Supply
>Date: Wed, 2 Oct 2002 14:18:02 -0400
>
>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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