Sounds like maybe your "LETA" (Trackball Interface Custom IC) is maybe
having thermal probs.
There really isn't much else that it could be since the spinner goes
directly into that IC and
only has small noise caps to ground and some helper resistors between
ground and +5V. I doubt that
the CPU is having problems reading the LETA or else your game would most
likely crash as well.
Even tho they are custom IC's, they are used on Crystal Castle and I
think Millipede boards.
Doug Jefferys wrote:
>
> On Sat, 6 Feb 1999, fishd wrote:
> >
> > I'm in the process of testing a couple of Major Havoc boards
> > with the Tempest/MH adapter but having problems getting the
> > spinner to respond.
>
> ...and while his fix was simple, that brings to mind something
> I saw a long time ago and never managed to fix.
>
> Running a Major Havoc board (no conversion kit) in a Tempest or
> Gravitar harness. Game powers up, plays fine for a few moments,
> but over time (30-40 seconds), the spinner becomes gradually
> less responsive and eventually completely unresponsive. Power-cycling
> the machine fixes the problem, but only for a few more seconds.
>
> It "feels" like an analog problem, say, a capacitor charging or
> discharging - the longer the machine is off, the longer it works
> before it fails again. Power off for a minute, get 30-40 seconds
> of spinner time. Power off for 5 seconds, get 10 seconds of spinner
> time.
>
> Obvious cause: Bad board.
> Unobvious fix: Sending the board to someone with a known working MH
> setup results in the board and spinner behaving fine.
>
> Obvious cause: Bad spinner.
> Unobvious fix: ...so why can I play Tempest normally?
>
> Obvious cause: Bad wiring.
> Unobvious fix: Problem reproduced on two separate wiring harnesses.
>
> Anyone else seen this kind of behavior? If so, what was the fix?
> (Things to do: Stick scope on CLK and DIR lines when I get things
> set up to test this again someday...)
>
> Later,
> Doug.
>
> --
> dougj |
> @ |
> hwcn.org |
Received on Mon Feb 8 11:26:20 1999
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