What's wrong with my SE/30?

[tattar8]

It works sometimes, but is unstable, and upon a reboot, I'll get a garbled screen, as shown in the photo.  It does chime, but does not death chime (but the memory checks are probably being skipped due to the ROMinator II that's installed).  It seems to me like this is some sort of RAM issue, but I'm not certain.  The machine was recapped, so there shouldn't be any cap gunk shorting out the board.

 

[IlikeTech]

Bad ROM contact? Try the rubber band fix.

 

[tattar8]

I tried that.  But wouldn't bad ROM contact also stop the chime from playing?

 

[tattar8]

Update:  It does seem to be the ROM.  I tried both a GGLabs MacSIMM and the ROMinator II -- both of them did the same thing.  Forcing a ROM checksum test from the debug interface reported a failure, as did a databus test at bit 1.  I swapped in the stock ROM, and that seems to boot reliably.  I think I'll leave the stock ROM in there for now since the custom ones seem to be unreliable in this machine, and getting to the ROM socket past the hard drive and Ethernet card is a big headache.

 

[techknight]

Motherboards for the SE/30 are a crapshoot when it comes to the custom ROMs. I dont know if its because the newer NANDs dont have the correct drive current or if its a TTL/CMOS issue or what. But some motherboards work fine with the custom ROM SIMMS, but a bunch of other do not. 

Might have to re-design the SIMM and buffer the address/data bus with HCT based chips. 

 

[tattar8]

The odd thing was it was working consistently with a MacSIMM, but after I swapped it out for a ROMinator II, neither worked consistently anymore.

The only other problem I can think of is that the slot on the motherboard is damaged and does not hold SIMMs, forcing me to either use the rubber band method or hot glue to hold any SIMM in place.  How hard is it to replace the slot?

 

[rplacd]

I'm thinking that maybe installing the ROMinator II might have pushed some gunk into the slot? It can't hurt to use contact cleaner or something to clean out the slot and check.