[ICOM] IC-PS35 problem

[Jim Hargrave]

Jim,

Have you placed a scope on the base of Q1? This transistor must be switched
with an AC component in order to conduct. C-9 is a blocking capacitor in the
Base circuit and must have some AC across it in order to turn Q1 on. The AC
frequency will usually be a frequency much higher than 60 hz. and may not
read properly on a DC voltmeter. The base path is via C-9. I agree you need
to get Q1 switching or it will not provide power to the main switcher IC-2.
It appears that IC-1 may be the oscillator that furnishes the AC voltage to
Q1. This is probably some kind of switching IC. I could not find a spec
sheet for it.


     73's Jim
      W5IFP


> -----Original Message-----
> From: icom-bounces at mailman.qth.net
> [mailto:icom-bounces at mailman.qth.net]On Behalf Of Jaime Gomez
> Sent: Tuesday, January 11, 2011 8:30 AM
> To: ICOM Reflector
> Subject: Re: [ICOM] IC-PS35 problem
>
>
> Hi Jim, Thanks, Before starting with the PS-35 I downloaded the manual, it
> was very handy because it has the schematics, but the other info is about
> calibration of a working PS-35, I need to make it work first and I do not
> understand why the transistor Q1 is not conducting....
>
> 73,
>
> On Mon, Jan 10, 2011 at 8:01 PM, Jim Hargrave <w5ifp at gvtc.com> wrote:
>
> > Jim,
> >
> > There is some test/adjustment info and downloadable manual at:
> >
> > http://www.ab4oj.com/icom/ps35/main.html
> >
> > Maybe something there will help.
> >
> >
> >     73's Jim
> >      W5IFP
> >
> >
> > > -----Original Message-----
> > > From: icom-bounces at mailman.qth.net
> > > [mailto:icom-bounces at mailman.qth.net]On Behalf Of Jaime Gomez
> > > Sent: Monday, January 10, 2011 4:50 PM
> > > To: ICOM Reflector
> > > Subject: [ICOM] IC-PS35 problem
> > >
> > >
> > > A friend of mine has asked me to help him with his PS-35 from
> an IC-751A.
> > > The power supply does not produce any output. I have checke all
> > components
> > > with exception of IC1 (N-110) which I do not know how it works
> > > and IC2. But
> > > I have traced the problem to the voltaje feeding IC2, which comes from
> > Q1.
> > > Q1 is OK, its emmiter has voltage but it collector does not,
> it is 0. I
> > > wonder if IC1 which is connected to the bas circuit of Q1 coulb be the
> > > problem.
> > > Anybody there who can help with this?
> > > Thank you, 73,
> > >
> > > --
> > > Jim, HK1N
> > > ----
> > > Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
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> > Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
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> >
>
>
>
> --
> Jim, HK1N
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
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