Would not running the 9420 from 240 VAC eliminate the problem of mains
voltage going high in the case of failed neutral wire? I find that mine
runs better on 240 VAC than 120 VAC, even though I have a dedicated 10 AWG
feed from my load center panel just for running high power 120 VAC loads.
DE N6KB
On Tue, Jun 4, 2019 at 11:06 AM Bob D. <ajamas.rn@gmail.com> wrote:
> Hi Gary-
>
> I used a surplus computer server switching supply on mine for a good while.
> I like having circuit diagrams for my gear and after some effort and no
> success in finding one switched over to a battery supply. The switching
> supply was very quiet. They are nice because they hold output voltage over
> a really wide range of inputs.
>
> It would be self serving of me to advise you to let it go as I am looking
> for a 9420 reasonably close to Atlanta:-). My Herc II is a later model with
> 2sc2879 transistors. I'll be comfortable with a 9420 and OVP limit at 15 V.
> A crowbar should do the trick. I would definitely NOT use the 9420 or any
> linear supply without protection. Squirrels chewed through my neutral on
> the AC service drop and took out a $300+ variable speed drive. Neutral has
> been spliced three times because of squirrels.
>
> I'm not familiar with the transistors used in other versions of the Herc II
> but will be surprised if any would be damaged by 15 V.
>
> My advice. Keep the 9420
>
> 73, -Bob
>
> 73, -Bob ah7i
>
>
>
> > Message: 5
> > Date: Sun, 2 Jun 2019 04:50:27 -0400
> > From: Gary Hendricks <k4mt1950@charter.net>
> > To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
> > Subject: [TenTec] 9420 VS Switcher
> > Message-ID: <7e01f6c1-c30e-7894-bd10-7881d9520e68@charter.net>
> > Content-Type: text/plain; charset=utf-8; format=flowed
> >
> > I have been looking at the schematic for my 9420 supply and it looks
> > like the output of the series regulators have no over voltage
> > protection. If my memory doesnt fail me I think when I was working at
> > TenTec I remember hearing the service guys talk about pass transistor
> > failures on this supply being somewhat common.
> >
> > Has anyone used one of the high current switching supplies on the
> > Hercules II amp? I see some avail at 14 volts and 100 amps with every
> > protection built in.
> >
> > Thinking about letting 9420 go and using one of the switchers because of
> > the protection built in
> >
> > Thanks
> >
> > Gary K4MT
> >
> >
> >
> >
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