Stargate board modification to run Robotron

jp.jones

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Hello,

I've been trying to research this and found two posts about the change. However, there aren't any screenshots. I was curious if anyone had done this successfully and would be able to provide screenshots especially of step 4 which is confusing to me as I'm not sure what this 'feed through hole' is or the location of the solder point in the last step.

The first is from http://www.robotron-2084.co.uk/techwilliamscpubsbamod.html
Second from from mikesarcade where they pulled the instructions from the October 1982 Star*Tech Journal which included pictures (does anyone have access to this .PDF?)


1. On the chip at location 5A (under C63), cut the foil (trace) that
connects pin 3 to ground.
2. On the chip at location 6F (under C75), cut the foil (trace) that
connects pin 3 to ground.
3. Jumper the newly isolated pin 3 of both chips together.
4. Jumper pin 4 of the chip at location 5A *** to the feed thru hole
(unused via) leading to pin 32 of connector IJ4 (above R26).***

If I knew exactly what step four meant, I'd be all set to do the mod. Otherwise I have to troll ebay to pay high prices for something that isn't guaranteed to work. Or - if you have a Stargate/joust/robotron board for sale then please PM me.

Thanks for any help you can provide!
John
 
Last edited:
I guess I answered my own question.

By reviewing the Later revision boards which do run stargate, robotron etc. - from pictures of the later rev boards, you can see the modification as it was also done at the factory.

Good job john! Thanks John!

- you're welcome

Talking to myself is a sign of impending mental collapse.
 
Sorry John, I missed this post. Sometimes the volume of repair posts slides stuff to the second page.

The through holes refer to the plated holes in the board that are filled with solder. They are used to extend traces from one side of the board to the other so that traces don't cross. When you look at the top (or bottom) of the board you will see traces that go no where and end in a dot. That dot of solder extends over to the other side of the board where it continues its merry way.

It's been a while since I looked into this, but if you compare the schematics between the Stargate MPU and a Robotron (Rev B) or Sinistar (Rev D) MPU it does make sense.

ken
 
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