Re: Re[2]: Re: MCR II issue

I have taken both buss bars off the board and the short appears to have
gone with them. I wonder if the dielectric between the planes had given
out. I will be working on making new ones and getting those in place,
then will check the board again.

As to caps (though I shouldn't have to smoke it now), there appear to be
no tantalums in the board stack at all. On the MCR VidGen there are
only electros and an axial package that looks kinds like a diode with a
beveled end. The rest of the boards (SuperCPU and SSIO) have a handful
of electros, some ceramic disc, the "diode" package and what look to be
some polypropylene caps.

We'll see where things stand tomorrow and what questions I have then. =)

peter jones wrote:
> 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 15:34:18 2007