[Heathkit] Re: [HEATH-TEMPE] SB-201/200 no output on any band

[Tom Chesek]

Thanks for the many replies. There are several ideas for me to persue when I 
get some time to jump back on that project. I'm anxious and curious to get 
it solved.

73,
Tom K3TVC



----- Original Message ----- 
From: "JF" <lhouseparker at LIVINGSTON.NET>
To: <HEATH at LISTS.TEMPE.GOV>
Sent: Sunday, October 19, 2008 1:42 PM
Subject: Re: [HEATH-TEMPE] SB-201/200 no output on any band


> 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
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> 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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