[Heathkit] SB-220

[Jim Brannigan]

The SB-220 manual has some useful trouble shooting tips......

When the first query was posted I turned on my SB-220 to check the plate
voltages....
Mine were waaay low.....my first reaction was un - printable, then I
remembered the voltage dropping resistors tend to age to the high
side.....whew....

Happy Thanksgiving

Jim


>   As I suggested, its probably a relay contact. But
> I would also check and make sure you have DC
> continuity from the 3-500 grid pins and chassis
> ground.
>
> Mark  WB8JKR
>
>
> On Thu, 25 Nov 2004 11:06:31 -0500 "Don Flenner" <w4ych at earthlink.net>
> writes:
> > Greetings All and Happy Thanksgiving,
> >
> > I recently acquired a SB-220 in a non working condition...The
> > problem is:
> >
> > When the antenna change over relay is energized I get no idling
> > plate
> > current...
> >
> > The 3-500Z's light up, I have checked them in another amp and get
> > the proper
> > idling plate current, the plate voltage reads 2500 in tune and 3200
> > in SSB.
> > I have changed the 5.1 volt zener, checked the wiring of the antenna
> > relay.
> > The plate current meter deflects when a put an ohm meter across it,
> > so I
> > amuse the meter is OK.  Also, as a further test to make sure it was
> > not a
> > meter problem. I hooked the amp to a transceiver. With the amp off I
> > get 100
> > watts out. When I turn the amp on and press the PTT, the relay
> > energizes in
> > the amp but no output.
> >
> > Sure could use some guidance from the knowledgeable on this
> > reflector.
> >
> > Thanks in advance.
> >
> >
> > 73,
> > Don, W4YCH
> > http://www.home.earthlink.net/~w4ych