Re: How do i check the clock circuit?

Joel,

   First, you're going to want to master using that logic probe that's in
the mail. They're simple to use. It should have a light that indicates a
toggling signal in addition to a "high" and "low" indicator. Some logic
probes will simply light "high" and "low" at the same time in the event of
a toggling signal.

   You'll want to use this toggle indicator as a means of sensing activity
on clock lines. Please be aware that this doesn't mean the clock is
"perfect" (you'd need an oscilloscope to determine that). However,
"toggle" should be fine for now. I've debugged/fixed many PCBs with just a
multimeter and logic probe.

    Next, all clocks originate at the oscillators, so start there and work
your way through the ICs to which this oscillator connects.

    Hopefully this minimal info at least gets you started :-). If you
can't wait and want to see if your clocks are toggling now, you could use
your multmeter. First, you'd want to measure Vcc at the chip/oscillator in
question (should be near 5.0V). If you measure the clock line with your
meter, you should get a reading about half that (around 2.5V).

Ed

On Mon, Sep 23, 2013 at 6:06 PM, Joel Griffin Dodd <griffindodd@gmail.com>wrote:

> Hi Guys.
>
> I'm going to attempt to repair my Star Wars board set as it won't boot.
>
> Never done this before, but I do have some advice as to what to look for
> coming from a repairer with a good rep. Everyone in the community with a
> good reputation is slammed with board work and not accepting new jobs, so I
> thought this would be a good opportunity for me to start learning the art
> of board repair.
>
> Unfortunately I don't have any background in this or electronics so I'm
> coming in very green.
>
> First thing I have to do after checking all the voltage test points is to
> check the clocks on the board and make sure they are all where they should
> be.
>
> I have no idea what this means or how to go about it, what to look for
> etc. I do have a decent Multi-Meter and I have a logic probe coming in the
> mail the next few days.
>
> So, where do I find these clocks you speak of, and what is the actual
> process I need to perform to check them for problems?
>
> Many thanks
>
> Joel
>

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Received on Mon Sep 23 18:27:32 2013