Need Info: "LH Research" Power Supply

From: <(>
Date: Tue Jul 6 17:35:34 1999

> Date: Tue, 6 Jul 1999 19:14:21 -0700 (PDT)
> Reply-to:
> From: Dwight Elvey <>
> To: "Discussion re-collecting of classic computers" <>
> Subject: Re: Need Info: "LH Research" Power Supply

> Kevin McQuiggin <> wrote:
> > Hi Gang:
> >
> > This is a longshot, but I am looking for a schematic (or even a pinout)
> > for an LH Research power supply, model number IM203. It's 120VAC to 5
> > VDC_at_8A, 12 VDC and -12 VDC both at 1.5A.
> Hi
> I don't know the particular supply you are looking at. The first
> thing to determine is if it is an analog or switcher.
> This is most easily determined by the ratio of transformer space
> to electrolytics. One big transformer and only a couple of large
> electrolytics and it is analog. Small transformer and a lot
> of electrolytics ( some rated for high voltage ) and it is a
> switcher.
> Where you go from here is related to what you have.
> Dwight

Be careful, I have seen switchers that looks almost like analog per
your descriptions and few analog ones looks like complex switcher.

Switchers: Only talltale item: solid ferrite core and small, tends
to have copper band; switcher. Analog PSU tend to have soft iron
lamites and bit heavy and tend to hum like a bee sometimes.
Switchers sometimes squeal and usually quiet.

Received on Tue Jul 06 1999 - 17:35:34 BST

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