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From: Lawrence Galea <9h9mhrlaw@gmail.com>
Date: Wed, 7 Jun 2017 21:12:15 +0200
Message-ID: <CAFDVXLkiP+bL2eV4uRog4UG6cwVzqvmnfqXmFr1bQsqETqi=oA@mail.gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Decoupling linear PSU
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Hi Chris,
Did you Try capacitors across the supply lines right at the output
connectors and also from both + and - to earth?
Did you try the same at the mains input with suitable voltage rating?
Regards
Lawrence

On 6/6/17, Chris Wilson <dead.fets@gmail.com> wrote:
> Hello LF'ers,
>
>  I have had a few issues with my lovely old Farnell H60/50 linear
>  bench power supply. It'll do 60V @ 50A but I suspect it's last couple
>  of uncontrolled output voltage failures may have been caused by RF
>  getting into it, maybe up the output leads, maybe elsewhere. The
>  manual makes mention of using caps of "a suitable value" across the
>  output, or each output pin to ground, when used to power "transient
>  loads" ; it's far from clear what's meant. The -ve floats relative to
>  chassis ground. What do people recommend as a means of stopping RF
>  getting in via the + and - output leads please?
>
>  It has SCR control on the transformers primary to keep the voltage
>  drop across the huge pass transistor tunnel down to around 8V, this
>  seems to go haywire at random times when powering my TX, and the
>  2N3055's don't like 103V into them. Worst case scenario should be
>  73V, but I am pretty sure SCR control fails and the secondary rises
>  to its full potential. Thanks.
>
> --
> Best regards,
>  Chris                          mailto:dead_fets@gmail.com
>
>
>