SB-201/200 no output on any band

[JF]

Something to check: my 200 once suddenly had no output with nothing
obviously wrong - turned out that one of the hard to see RF output line
through-chassis bare wires had somehow come loose where it came through
the hole from underneath and was soldered to its end point in the
tube/tuning cap compartment. There are only 3 like that, all connected
together under the chassis and emerging near the front: 2 are under and
go to the LOAD variable cap, and the other is under the bandswitch where
it connects to both sides of the rear portion and then via a bare wire
to the rear of the 20/40/80 meter final coil L7. Are any of those
missing or unsoldered?

As that is the RF output line your problem could very well be somewhere
in there, but might also be elsewhere. I would suggest pulling the
chassis out of the cabinet and going through all the assembly steps in
the manual, verifying the continuity & soldering of each wire and
placement of each part, especially the bandswitch connections, as you
say it was replaced and it would be easy to get connections wrong.

If your 200 once had any arcing from parasitics (or in the one the
replacement bandswitch came from) some of its contacts may have been
damaged or vaporized, and if so may be hard to see. You can't get your
fingers into the bandswitch while everything is installed, so you
would have to take it out for a real inspection, something only a
dyed-in-the-wool Heathkit fanatic would love. You might be well
advised to start looking around for another switch.

73

John F.  KE5ZB


















Tom Chesek wrote:
> I have an SB-201 which was converted to an SB-200 equivalent with a complete
 > bandswitch swapout. I cannot tell you if it ever worked after the swap.
 > This amp has the Harbach power supply mod and antenna relay including the
> I've tried drive on each band from 30 watts to 100 watts with no output
 > measured on the amps' meter or on the watt meter inline to the 50 ohm antenna
 > load.
> Tom K3TVC

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