Hypersports z80

[Shinydaz]

I have a hypersports here with a bad top board, I've checked the konami 1 custom, roms and changed a few dodgy ttls but it still fails to boot(purple screen). Would a bad z80 stop it from booting? It won't run enough to try the test rom. I thought the z80 was just responsible for the sound on the top board but I could be wrong, cheers.

Edit: Bottom board tested good.Shinydaz2018-03-13 11:08:59

 

[RGP]

I actually think the sound CPU boots first to be honest, its not too clear.

Check around that Z80 for the watchdog kicking the reset line at pin 26 and if you have a clock running at pin 6.

Also check that /NMI and /IRQ aren't stuck low on the z80.

 

[Shinydaz]

Thanks for your input James, much appreciated. I'll do some more testing at the weekend.

 

[shoestring]

Repaired one of these recently. It was hell...

Unfortunately I replaced the z80 [ half of the pins were floating ] and fixed the weird RST behaviour before getting the game to a booting stage. So I don't know if the game would still refuse to boot with a bad z80 on the sound board or not.

If this is any help, what I can tell you is that once I was able to get my board booting I still had no sound. /OEs to the sound EPROMs were stuck, once I replaced the two 2114s the sound started working except for the speech.

RST signal originates from the bottom board [ A1,G2,C4 and the 504 custom ] and passes through to the top board via CR13, D18 and B2 . Check your CR13 connector/cable too.
shoestring2018-04-01 13:45:27

 

[Shinydaz]

Thanks for the input, will take another look this week.