Re: Asteroids test switch and circuit

Perhaps the Watchdog is disabled?

John :-#)#

At 06:05 PM 15/11/2002 +0000, Phil Morris wrote:

>I have an Asteroids board that, when switched between test and game mode
>via the test switch, *won't* switch between the two unless you flip the
>test switch (ie ground pin L) *then* press the reset button (a correctly
>functioning board will switch as soon as the test switch is operated, ie
>there should be no need to press the reset button).
>
> From looking at the schematics I see that the TEST signal is read by the
> LS251 at L10 and the LS161 at C5, but these are changing states as they
> should when edge connector pin L is grounded.
>
>So what other part of the circuit would cause this problem? I could swear
>that I've read about this somewhere in the dim and distant past, but I can
>no longer find the reference.
>
>As an aside, this board has a VSM fault - it will only play (blind) if pin
>1 of the LS42 at L6 is cut ..... and we all know what a pain the VSM is to
>diagnose.
>
>
>
>Thanks,
>Phil
>
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Received on Fri Nov 15 11:00:29 2002