Greetings to all,
Just had another SB-220 come in with a dead filament transformer.
Someone had replaced the original transformer, that had also failed, with a
brand new, expensive, Peter Dahl transformer without fixing the cause of the
problem. Of course, the new Peter Dahl transformer soon failed.
What caused the problem in the first place? The electrolytic in the
relay/bias power supply was leaking badly causing the bias winding to
overheat and short, internally, to the primary windings. As I see so
often, spending a couple of bucks on a new capacitor would have saved both
the original transformer, and the new, $200, Peter Dahl unit.
If you decide to do a little preventative maintenance and change
this cap, don't forget to do the bias mod, also. A very small investment in
money, and time, can save a lot of frustration, and cash, in the future.
Remember, it your amp has the original capacitor in it, as most do, it could
easily be close forty years old.
73 de Lon, K5JV
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|