Re[2]: Re: MCR II issue

-----Original Message-----
From: EvilJim <eviljim13@comcast.net>
To: rasterlist@vectorlist.org
Date: Wed, 24 Oct 2007 08:53:50 -0700
Subject: Re: RASTER: Re: RASTER: MCR II issue

>
> Thanks for the steps here Peter/Rodger. I'll be looking into this
> some more today, after I trace where each leg of the buss is actually
> going. One of them is off the board already, still shorted.
>
> As far as the heating/smoking method, what I am hearing is to connect
> to the suspect board using the +5/GND pins on one of the 24pin headers,
> correct? Apply juice until something is obviously warm or actually
> fries from the current.
> Is this most likely to be quick, like a fuse upstream of a short? I
> am wondering if I will miss it and then it comes down to finding the
> damaged item, or if it will take at least long enough to actually see
> the component die. And I take it the beefiness statement refers to the
> PSU being able to output high current w/o shutting down, or frying itself?
>

the psu must be good enough to melt/cook the short and not itself,
it doesnt need to be 5v, it can be less - it's the current that matters.
there is a risk you could smoke a track instead - but it's low.

will it get hot or fuse or go bang? that depends on the current you supply.

Q: i dont have one of those boards for reference - is there any tantalum capacitors on it?
those little bastards are prime suspects if there are - i'v had them go like a blowtorch on space-invaders boards!

if you have tantalums then lift one leg of each and check with a meter - they are the one thing you dont want to provoke with a current-boost because they will burn the board.

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Received on Wed Oct 24 14:58:21 2007