Konami Gyruss - repair - boot issues

Flocke28

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Cologne, Germany
Hi all.. its hard to find a Gyruss pcb this days, so i bought a non working one. The pcb is very clean, no shorts between gnd and 5v, so i tried the first boot.. but only garbage on the screen.. i checked all eproms and found 11J (main cpu eprom) was not readable anymore.. i burned a new one and the game boots into the grid and resetting.. so i downloaded and burned the diagnostic EPROM..

I got three main issues: Ram 17C NG, Rom 12J NG and Konami1 not responding.

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i looked at the schematics in the area of 17C and tried to piggybacking LS245.. 13E seems damaged.. 17C was readable again, so i swapped th ic

IMG_1678.jpeg
IMG_0512.jpeg

the Konami1 has also some LS245 in his area, so i guess one or more is also bad.. 9DB0 signal looks strange.. but my stock of LS245 is running out.. so i ordered some and have to wait yet.. (i tried an other Konami1 ic but same issue, so i dont thing the Konami1 is bad)

When i inset the main cpu EPROM sometimes its start the game.. with 17C ok the sound of the game is correct.. but no sprites and stars

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Stay tuned for the next update 😊
 
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