GYRUSS board issues - Anyone seen this before....

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HI all,

I've started working on my GYRUSS I've recently picked up.
Currently testing the board in a Time Pilot cabinet, as they're the same pinout on the connector.

When I first powered this board I got nothing, I've since tested all the ROMS via the reader and verifying them on romident, then downloaded a Centuri rom set.
I had a few roms with issues and some with broken legs, these have all been swapped out fixed and it now seems I have a full working rom set.

I have a few Time Pilot boards that I swapped out and tested all the customs IC's bar the Konami-1 (CPU) IC.

Desoldered all 4x 2114 RAM in A11, A12, A13 & A14, installed sockets and new RAM in all.

Also have replaced some of the sockets of the ROMS and customs, but not all as yet.

I did burn myself the test rom that shoestring created and it passes everything, then boots into the game.

The picture attached is what I have on screen now after the above work...
Has anyone seen this, that could point me in some sort of direction ?

Sorry about the sideways pictures, couldn't work out how to get them the right way up...
 

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I have never worked on a Gyruss, but does that "noise" you see on the screen also appear when running shoestring's TEST rom?

paris
 
Well this has stumped me !

The other day when I started working on this board, I tested the +5v.
I had to turn it up a tad so the IC's were close to +5v and left it at that.

I decided to have a play with the voltages again just now and the further I lowered the voltage the clearer the picture become until I got whats in the pictures attached.

I measured the voltage at the power supply once the picture become clear and it was at +4.6v.
I haven't yet measured at the IC's, but it this doesn't sound right to me ??
Or is this normal for GYRUSS PCB's ?

I'm glad its all working, but I feel there's still something wrong as the voltage has to be set so low.
 

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I was going to suggest a troubleshooting approach but you got it sorted, great!
 
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I think this is normal for Gyruss.

I have my +5 set to around 5.2v at the edge. At the chips it runs happily at 4.8v.
 
well, the problem with all these Konami games is their harnesses only have a single ground wire running back to the power supply. factor also you have a board being powered by another board with a single return, and you're looking at a recipe for disaster. any Konami game I come across I modify by opening the +5 and ground traces on both boards and soldering 18 gauge wires to them to run back to the power supply. this almost neutralizes the awful voltage drop and you're not relying on the piggyback method, you're feeding power directly into the sound board I think it is. or is that video board? I can't remember now!

without doing this you will eventually damage the edge connector, it'll get too hot cause of the poor return path.

like a lot of Konami games these things should work as low as 4.2V. maybe then they'll freeze up. :D
 
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