ShootTheCore

If you'd like to try your Spiderman ROM board on my System 32 base board, shoot me a PM.

Suggestions:
-We've ruled out bad Z80 CPU, Z80 RAM, and IC21 GAL, and final amp that only leaves the 315-5385 custom.
-I strongly recommend trying the Spiderman ROM board on another System 32 baseboard.
-If the ROM board confirms good, reflow the 315-5385.
-If the 315-5385 is still dead, replace it.

@ohpoorpup.bsky.social OK, so here's what I learned:
- There are 4 Sound ROMs with Spiderman (IC22, 26, 31, 35)
- The OE pins for all four are driven by outputs from the GAL chip at IC21
- The GAL Input lines partly come from the Z80 CPU and partly from the 315-5385 Custom
[continued]

That looks really clean! And no protection mechanism on that one too which is definitely nice. Thank you for the pic - I’ll do some further digging on the schematics and will let you know what I find out.

@ohpoorpup.bsky.social can you share a photo of your Spider-Man ROM board? As directly overhead as possible please so I can read the IC labels on the parts. I want to cross-check a few things against the schematics.

I’m thinking that your Z80 CPU is good and the Z80 RAM is good (so the diagnostic passes and you hear the pulse) but if the OE lines on the Sound ROMs are inactive then the Z80 isn’t able to pull data out of them for some reason.

Hmm…so no signs of life with another GAL then. Drat. It’s my bedtime here but I’ll take another look at the schematics tomorrow. Since you have an EPROM programmer, can you dump all four Sound ROMs and make sure they match the files in MAME?

There’s a protection bit set on the Sega originals, so you won’t be able to Erase or Write to it.

OK. Those should trigger as the Z80 runs. It’s possible that the GAL chip on the ROM board failed - it triggers the OE lines on those ROMs. Replacement part is a GAL16V8 and needs to be programmed with an EPROM programmer. I can program and send you one if need be. File is here: tinyurl.com/4mteukcw

Can you check the OE pin on the two Sound ROMs on the ROM board and see if they’re triggering? They should be Pin 24 on IC35 (27C010) and Pin 24 on IC31 (27C4000).

I’ll have to check the schematics later to refresh myself how the customs get involved in the sound generation circuit. At least you can safely cross the Z80 off the culprit list.

Apologies-I misconstrued what you meant when you said the Z80 clock signal looked like mine. If the clock signal looks healthy and the reset line briefly triggers at power on then check the M1 (pin 27) next. It’ll pulse regularly if the Z80 is processing code. If the Z80 is running, check the amps.

The Z80 clock signal comes from the two TTL chips above the crystal oscillators-IC23 and IC24. Check those before touching any customs.

Check the Clock and Reset signals on the Z80. It also could be a bad Z80 Audio CPU like I encountered. I think they fail more often than the customs do.

#RandomGameSaturday this time is Zelda Four Swords Adventures. Four players each link a GBA to a GameCube console to embark on a unique adventure where the TV screen is a shared space but each player can split from the group to explore separately on their own screen. A peak couch co-op experience!

Thank you!

Amen!

I finally sorted out the remaining issues with the sound on this Golden Axe 2 Revenge of Death Adder #arcade board. Detailed writeup at jammarcade.net/golden-axe-i...

I helped a friend calibrate his Sony KV-36FV16 CRT today. The greypoint range dialed in nicely except for a tiny blip in the 0-10% IRE that barely matters. The geometry is also surprisingly good for a flat screen Sony!

Hit the nail on the head IMHO.

Send some of that snow my way!

Post a game you remember playing that nobody else remembers.

SMD soldering takes practice-and the right tools help! I use an iron with a small, flat blade tip, a microscope, a hot air station, tons of flux and sewing needles to straighten any bent pins.

Regarding SPI security chips, AFAIK there’s nothing you can do except swap parts from a donor.

I just published a detailed writeup of this repair on JammaArcade.

jammarcade.net/seibu-kaihat...

A busy evening tonight repairing both a Seibu Kaihatsu SPI #arcade board and Raiden Fighters 2 cart. SPI Revive by Trap15 brought the SPI board back, and reflowing the solder on several SMD ROMs fixed the jailbar graphic corruption in RF2.

Check out his majesty!

I thought I was done with this Sega System 32 #arcade board but playtesting revealed that it would still freeze up periodically. It seems that another TTL clock buffer just to the left of the one I just replaced is bad as well - I even cross-tested it with two testers to be sure. Very strange. 😑

That’s disappointing. And I was just playing it the other day.

I got a dead Sega System 32 #arcade board up and running again yesterday. Culprit was a dead TTL clock buffer chip. Full writeup on the diagnosis coming soon.

Poor Sega. 😢