Re: Tempest Analog Generator Question

On Sun, 2 Dec 2007, Matt Rossiter wrote:

> I'm trying to figure out a weird issue on a tempest board in the AVG
> Section. The game is running blind and I traced the fault down to
> the outputs (pin 2 and 15) of both LF13201 analog switches.
>
> I've put the schematic here and dotted where the good/bad signals
> are. http://games.rossiters.com/images/Tempest.jpg

> Does anyone have any idea why the output on pins 2 and 15 of both
> analog switches would not work when they are getting proper inputs?

The chip is busted ? :-)

All the analog switch does is determine if the output is inverted or not
(for cocktail mode). If you are replacing it anyway and don't want to wait
for the new ones to arrive -- pull the chip, put in a socket, jump the
pins for one of the signals (inverted or not invereted) with a piece of
wire and see if it works.

If it's not in a cocktail table and you don't plan moving the board to a
cocktail table you could just leave the correct ouput directly
connected and not use the switch at all, and have one less thing to break.

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Chris Candreva -- chris@westnet.com -- (914) 948-3162
WestNet Internet Services of Westchester
http://www.westnet.com/
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Received on Sun Dec 2 21:51:33 2007