Re: No Replies to Tempest tech question?

Al Warner wrote:
>
> Question 1: Should rearranging the ALU chips produce different problems
> on the screen or is it all one big matrix and that won't make a
> difference? I tried cleaning / moving the chips around, but the results
> are the same.

Moving the chips should not result in any changes. If there are, you have a
bad ALU.

>
> Question 2: Is there a chip / component that controls both Pokeys and
> ALU?

Yes. The CPU controls both of them. But that doesn't help much.

Take a look at the schems to see if the Pokey's and Mathbox go through
a common buffer (LS244). Also, you may want to check the Self Test Screens
to see if you have a mathbox problem.

>
> Question 3: Has anyone seen these symptoms before?
>
> Before you ask, Resoldered interboard connector pins (removed old
> solder, replaced with new) on both boards.

If your ALU's are have blackened pins you may want to clean them. Or if
you have Tan colored sockets, replace them.

Sounds like you have a bad connection somewhere. Does pressing on the boardset
make matters worse?
Received on Tue Aug 31 12:11:13 1999