SB-401 Power Supply problems

[mike bryce]

dale...

first things first.

let's bypass the internal meter. Dig out the VTVM and check the B+ with
that. If the voltage is stable, then the problem is with the rig's metering
circuit.

but,

if you see the same thing, unsolder the large red wire coming out of the
supply that goes to the finals, then recheck the voltage...

if the voltage is stable now, the problem will be common to the +800 volt
circuits...


--
Mike Bryce WB8VGE
SunLight Energy Systems
"Electricity at the speed of light"

> From: Dale Mason <dmason at SOFTCONNECT.NET>
> Reply-To: Dale Mason <dmason at SOFTCONNECT.NET>
> Date: Wed, 22 Nov 2000 11:30:38 -0700
> To: HEATH at LISTSERV.TEMPE.GOV
> Subject: SB-401 Power Supply problems
>
> Hi,
>
> Trying to resurrect my SB-401 after 20 years in the closet.
>
> Hopefully someone can diagnose the problem I'm now having.
>
> Was not getting any high voltage to the finals, so I replaced the two large
> electrolytic capacitors, their asociated bleeder capacitors, and the four
> rectifier silicon diodes (pretty much the entire H.V. circuit, which is
> using the two electrolytics to double the transformer voltage to 700-odd
> volts).  Now when I flip the meter switch to HV, the needle very rapidly
> and repeatedly gets pinned and zeroed, pinned and zeroed.
>
> The diodes that I used, by the way were Radio Shack "switching diodes" with
> the same voltage and current ratings as the original silicon diodes.  The
> replacement electrolytics were from Ron Oxley.
>
> Any help that you can give would be greatly appreciated.
>
> Thanks,
>
> Dale Mason, KD9LW
>
> Listserver Subscription:listserv at listserv.tempe.gov - "subscribe heath 'name'
> 'call'"
> Listserver Submissions: heath at listserv.tempe.gov
> Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff heath"
>

Listserver Subscription:listserv at listserv.tempe.gov - "subscribe heath 'name' 'call'"
Listserver Submissions: heath at listserv.tempe.gov
Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff heath"