Flocke28
Active member
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.

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


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

Stay tuned for the next update
I got three main issues: Ram 17C NG, Rom 12J NG and Konami1 not responding.

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


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

Stay tuned for the next update
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