> > When I unplug J3, disconnecting the regulator from the transistors, I
> get
> > a nice solid stable 28.5V from the LM317, and I can adjust it up or
> down.
> > As soon as I connect the regulator output to the transistor bases, I
> > measure 44.0V on the output of the LM317 and at the transistor bases.
> No
> > adjustment regardless of the pot setting.  The collectors of Q1 & Q2 are
> > at 44.7V.  This happens with or without a load on the emitters of Q1 &
> Q2
> > - I used a 100 Ohm resistor for a test load.  No appreciable difference
> > with or without it.  The LM317 stays cool the whole time.
>
        -----Original Message-----
        From:   Olin Lathrop [SMTP:olin_piclist@EMBEDINC.COM]
        Sent:   Tuesday, November 05, 2002 1:01 PM
        To:     PICLIST@MITVMA.MIT.EDU
        Subject:        Re: [EE]: Power supply rework (again)

> Are you really really sure the pass transistors are wired correctly?  It
> sure sounds like the 40V is being conducted right thru one of the
> junctions to the LM317.
>
>
Just wondering, they definately aren't PNP transistors are they? :o)

Mike

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