Re: Taito Asteroids Short and Solder

Since the cap is probably an RF filter cap (each IC on the board has one righnt
next to it), it is connected directly to the ground and 5 volt rails. Thus,
there are only two possibilities it blew: 1. The 5 volt was not 5 volts, but a
LOT higher. Very unlikely, as they can take probably hundreds of volts without
blowing. The second possibility would be the cap itself, which was hoted
internally, thereby bl;owing the fuse. The second fuse could probably take more
current than the short circuited cap, thereby blowning the latter. Cut the cap
from the board, fire it up and see what it does. It is not absoltely needed to
make the board tick.

Mendel

> Paul Sommers wrote:
>
> Gang,
>
> Started to work on my Taito Asteroids board last night.
>
> Plugged it in and it blew a fuse!
>
> Looked around the board which was clean, no noticable shorts, cleaned bits and
> pieces, cleaned edge connector. Replaced the fuse, plugged it in and this time
> it blew a tant cap near the 2114 rams. Pop!!!!!
>
> So clearly there is a short - what is the best way to find it? Could it have
> been the cap or was the cap just the weakest point.
>
> Without further advice I wasn't going to do anything else, I thought I would
> socket the rams anyway.
>
> I can't budge the solder. It won't melt except a bit. I tried flowing new
> solder to it, but it kind of just sat on top. Anything I should be doing for
> old solder?
>
> As always - thanks.
>
> Paul
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Received on Thu Nov 9 19:07:22 2000