[1000mp] Re: 1000mp digest, Vol 4 #207 - 4 msgs

[George, W5YR]

No argument from me, Dick - just seemed like overkill for a simple problem.
Ten seconds with a DMM and you know which way to turn . . .

Thanks for the note!

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
"Starting the 58th year and it just keeps getting better!"
w5yr@att.net





----- Original Message -----
From: "Dick Carroll;" <dixie@townsqr.com>
To: <1000mp@mailman.qth.net>
Sent: Wednesday, September 03, 2003 12:52 PM
Subject: [1000mp] Re: 1000mp digest, Vol 4 #207 - 4 msgs


> >  George W5YR wrote
>
> > Sound like the transistor is just a simple switch for the relay. When
the
> > relay should be on, the base should be at an appropriate voltage for the
> > circuit in order to turn the transistor on. If the base is being
switched by
> > the T/R logic and the relay doesn't come on, that pretty well points to
the
> > transistor as being defective - replace it. If no base voltage change is
> > observed, then start working backwards through the T/R logic from there.
> >
> > I wouldn't want to argue about it, but a curve tracer to evaluate the
> > transistor is a little overkill. It either switches or it doesn't.
>
> All very true, George, but using a curve tracer will allow sometimes you
to do
> troubleshooting without powering up the rig or removing any components.
You can often get
> a good idea of the status of a PN junction device quickly and easily.
>
>   I have a bit of trouble these days, (what with a bit of arthiritis in
the hands and
> eyesight that doesn't work near as well as it used to)
> with probing live solid state circuits with VOM probes-one slip and you
can easily "fix"
> it good!
>  Of course one has to be careful where you use a curve tracer since it
does introduce
> voltage into the circuit under test, and can thus destroy junctions under
the wrong
> circumstnces. One needs to evaluate the circuit first.
>
> 73, Dick W0EX
>
>
>
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