Hi,

How can I test a smt capacitor in "live" circuit with a oscilloscope?

Thanks.

s...@gmail.com wrote:

> Hi,
> 
> How can I test a smt capacitor in "live" circuit with a oscilloscope?
> 
> Thanks.
  Its not so much testing the capacitor in a live circuit, you need to
know how the circuit is suppose to function to even start thinking of
using an O-scope. For that, you need a service manual or schematic and
understanding of what you're looking for and at.


-- 
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:
    You need brains before thought!
"
http://webpages.charter.net/jamie_5";

Jamie wrote:
> 
> "I'd rather have a bottle in front of me than a frontal lobotomy"
> 
> "Daily Thought:
>     You need brains before thought!


   Looks like you're out of luck, again!


-- 
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

On Sun, 24 Feb 2008 16:20:14 -0800 (PST), s...@gmail.com wrote:

>Hi,
>
>How can I test a smt capacitor in "live" circuit with a oscilloscope?

As Jamie notes, testing in an operating circuit requires knowledge of
what to expect to see if the component is operating normally.

For in-circuit testing on a de-energized circuit, however, it is
possible to get some idea of what's "going on" with an o-scope and a
stimulator circuit. There are commercial versions (see Huntron
Tracker) but a home-made rig is pretty simple. See a discussion at
<http://octopus.freeyellow.com/octopus.html>; and similar.

Using an octopus isn't magical and is not likely to yield useful
results unless the effects of the surrounding components can be
determined. It's most usefully employed when there is a known good
card against which the suspected failure can be compared.

-- 
Rich Webb     Norfolk, VA

> Using an octopus isn't magical and is not likely to yield useful
> results unless the effects of the surrounding components can be
> determined. It's most usefully employed when there is a known good
> card against which the suspected failure can be compared.

How can I determine effects of the surrounding components? I've got a
component
analyser PTS model 8001.

Thanks.

On Mon, 25 Feb 2008 11:21:50 -0800 (PST), s...@gmail.com wrote:

>> Using an octopus isn't magical and is not likely to yield useful
>> results unless the effects of the surrounding components can be
>> determined. It's most usefully employed when there is a known good
>> card against which the suspected failure can be compared.
>
>How can I determine effects of the surrounding components? I've got a
>component
>analyser PTS model 8001.

I'm not familiar with that piece of equipment; didn't see anything on
a quick Google search.

WRT the surrounding components, if you don't have a schematic then all
you can reasonably do is trace out what you can and apply brain power.

-- 
Rich Webb     Norfolk, VA