Re: OT: Vortex issue

["d.nix" <d.nix@comcast.net>]

Generally speaking, you cannot test most components in circuit, as the
surrounding connections and components prevent you from getting proper 
clean
values of just the questionable part... Some times, depending on the type 
of
part and the type of circuit, you can measure voltages across the various
components and deduce if its functioning properly - but you *really* need 
to
know what you are doing, and know what a properly fucntioning device should
measure.

You also have to do this with it powered up, and if you make a mistake and
short out the wrong terminals, you can fry stuf and cause more damage. As
well as shock yourself....


----- Original Message ----- 
From: "Clifford Novey" <cnovey@gmail.com>
To: <Loopers-Delight@loopers-delight.com>
Sent: Wednesday, May 12, 2010 8:43 PM
Subject: Re: OT: Vortex issue


> U32 is actually soldered to the board which is a pain- wish it was in a
> socket. I need a book to teach me the basics of this like how to test
> components,etc. I have a small cheap multitester but don't know much else
as
> far as how to use it on installed caps,diodes,etc. and what settings and
> values should show. Tempted to run to Radio Shack before they close and
get
> a nicer digital one.
> C
>
>   Not being able to measure on your device, I can't tell too much..
> >> Could be the output opamp U32 (Motorola MC 34072, dual opamp) or the
> >> output voltage swing clamping diodes D12/D13 (1N4148 small-signal
silicium
> >> diodes).
> >>
> >> Those are located fairly close to the jacks, and I believe labeled on
the
> >> PCB close to each component.
> >> IIRC U32 is in a socket, so it's easy replacing it.  I don't know 
>about
> >> availability today; it's possible you may need a replacement part.
> >>
> >>
> >> --
> >> rgds,
> >> van Sinn
> >>
> >>
>