Re: Fixing Asteroids explosions

FYI:

I've noticed this on my Asterock (Italian Asteroids bootleg) too and always wondered it it was a defect because I too saw it on most Asteroids cabs.

Maybe worthwhile to have a look the Asterock schematics too....

Op 3 feb. 2013, om 19:47 heeft Ian Eure <ieure@mac.com> het volgende geschreven:

> Pretty much every Asteroids I've ever played has had an intermittent issue where explosions sometimes display as a flat, inconsistently dashed line instead of the animated dots. They can be either horizontal or vertical, it can happen one in five or ten or fifteen explosions. Everything else works fine. I have heard that this is caused by bad LS161 counters.
>
> I'm wondering if this is usually the case, and if so, whether there are any good techniques to isolate the faulty ICs. There are a ton of these on the PCB and I don't want to socket everything to track down a single faulty IC. I don't have an IC tester, scope, or any advanced diagnostic tools, just a logic probe. The problem is so intermittent and only occurs during gameplay, so it seems like the probe isn't going to be much help in this case.
>
> I read on the (sadly now defunct) usbdesigntech.com site that the following 161s were very prone to failure:
>
> Type SA 74LS161 with a date code of 8108
> Type SA 74LS161 with a date code of 8045
> Type SA 74LS161 with a date code of 8046
>
> I could start by swapping any of those I find, but I was curious to know if there is a better way to do this.
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André Huijts
andre.huijts@upcmail.nl

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Received on Sun Feb 3 14:58:23 2013