Switching PSU Theory of Operation / Repair Tips & Techniques

From: Dwight Elvey <elvey_at_hal.com>
Date: Wed Jul 26 14:08:50 2000

Hi
 I'm still puzzled over the 600V reading. My guess
is that there is a problem in the meter. As far as I know,
the inputs are usualy configured as a doubler when used
with 115V and a bridge when used for 220V. I don't
recall the circuit but I remember it was a clever trick
in that one could change it with a single jumper.
 What a BBU?
Dwight



Douglas Quebbeman <dhquebbeman_at_theestopinalgroup.com> wrote:
> >
> > > I am still puzzled as to how it gets 600V without either other large
> > > capacitors, or a mains-frequency transformer.
> >
> > Ditto.
>
>
> --------------------- +
> to BBU
> |
> |
> +---------{ MCI 307138 }---------------+--------------------
> +ve
> / \ | + |
> / \ ===== / 12k ohm
> / \ ----- \ 5%
> / \ | - /
> ----* *---------------------------------+----------*
> | \ /| | + \
> | \ / | ===== / 12k ohm
> | \ / | ----- \ 5%
> | \ / | | - |
> | ----------{ MCI 307138 }---------------+---------------------
> -ve
> | | |
> | | |
> | | ---------------------- -
> to BBU
> | |
> | |
> | |
> 115v Load 115v Neutral
>
> > > I will just ask again -- this thing does run off 115V, right?
> >
Received on Wed Jul 26 2000 - 14:08:50 BST