TECH: nemesis HELP

[MarbleMad]

[ukvac] TECH: nemesis HELP
I've got a nemesis PCB here. It boots into self test but there's several
characters missing (Rs and Ts) and it giving the error message:

COLOR RAM BAD
well actually it says:
COLO AM BAD

Anyway, anyone know the where on the board the colour ram is?
---
James G Watt
http://www.kinetic-arts.co.uk
Part of the Video Arcade Game Collectors WebRing.

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[John Bennett]

[ukvac] Re: TECH: nemesis HELP
Hi

The colour Ram is at 14K and 15K. These are a pair of 2128-15's selected by the 74LS32 at 15J.

You may also want to check -

5K and 5J - 74LS273 the output buffers
8K and 10K - 74LS245 - Data input buffers from main Ram
16K, 17K and 18K - 74LS157 - Address Line Buffers

I know this is correct for a Konami board, may be the same for a bootleg i'm not sure.

Hope this helps

Andi



DATA Imported from archives: originally posted by (andi@the-fab-four.co.uk)

 

[John Bennett]

[ukvac] Re: TECH: nemesis HELP
Just as a follow up.

14K - Controls the Red and half of the Green

15K - Controld the other half of the Red and nall of the Blue

Regards

Andi

I have emailed you the schematic for it too.



DATA Imported from archives: originally posted by (andi@the-fab-four.co.uk)

 

[MarbleMad]

Re: [ukvac] Re: TECH: nemesis HELP
thanks for the help. been doing a little board swapping and have
discovered the missing characters is not related to the colour ram
problem. it's something on the bottom board that's causing that:/
---
James G Watt
http://www.kinetic-arts.co.uk
Part of the Video Arcade Game Collectors WebRing.

You are in a maze of twisty little passages, all alike.



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[Dave2084]

Re: [ukvac] Re: TECH: nemesis HELP
At 08:19 am 15 05 01, you wrote:
>Hi
>The colour Ram is at 14K and 15K. These are a pair of 2128-15's selected
>by the 74LS32 at 15J.
>
>You may also want to check -
>
>5K and 5J - 74LS273 the output buffers
>8K and 10K - 74LS245 - Data input buffers from main Ram
>16K, 17K and 18K - 74LS157 - Address Line Buffers
>
>I know this is correct for a Konami board, may be the same for a bootleg
>i'm not sure.

Does this mean you are reasonably confident at repairing Konami GX-400 PCB's?

I have two Salamanders, which share the GX-400 bottom board with Nemesis
that are faulty. The first has every other vertical line of all sprites
and some text missing. The other has no sprites and when used in a nemesis
the top (or bottom I can't remember) half of the screen is solid blue. For
both boards the game plays fine and in all cases the top boards are fine
with a fully working bottom board.

Any ideas?

Failing that has anyone got a KONAMI Salamander/Konami GT/Nemesis/City
Bomber Boardset (I think all these used a GX-400 as the bottom board ...
correct me if I'm wrong or there are more) that has a faulty TOP board to
trade so I can make a working set? I have lots of untested stuff to trade
at the moment ....

Dave Langley
www.robotron-2084.co.uk



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