SE/30 Simasimac persists after recap

[techknight]

Slow chimes = unable to see RAM properly. could be RAM traces to the IC below the sockets, or the muxes themselves are bad. 

 

[Riilu]

So I removed the RAM upgrades installed and ran it on just the 4 sticks, i powered it on, and instead of the simasimac pattern, the screen had that normal screen background as expected, but the floppy disk icon didn't appear, so i figured "oh maybe it needs the floppy drive" so i plugged the FDD back in since the HDD doesn't work and i turned the machine back on again, but now the simasimac pattern was back, so I turned it back off, unplugged the floppy, turned it back on, and now the simasimac pattern was still there, restarted yet again, and it still had the simasmiac pattern. This computer really isn't nice to me.

 

[K55]

So I removed the RAM upgrades installed and ran it on just the 4 sticks, i powered it on, and instead of the simasimac pattern, the screen had that normal screen background as expected, but the floppy disk icon didn't appear, so i figured "oh maybe it needs the floppy drive" so i plugged the FDD back in since the HDD doesn't work and i turned the machine back on again, but now the simasimac pattern was back, so I turned it back off, unplugged the floppy, turned it back on, and now the simasimac pattern was still there, restarted yet again, and it still had the simasmiac pattern. This computer really isn't nice to me.

You try just giving it a nice hard wack on the analog side of the case? I have a fully recapped se/30 and if I don't use it for a few weeks it gets grumpy and dosen't post to the happy mac. Hitting it fixes it. :^)

 

[techknight]

thats a sure sign of intermittent connections still present. Whether its internal to an IC or traces/physical connections will require troubleshooting. 

 

[Riilu]

Should I wash it off with vinegar or ethanol? It could be soapy residue from previous attempts to clean it off. I do know soap can be conductive.

 

[Riilu]

Even with the ATX upgrade, i get -10.99 volts on the -12v line going to the motherboard, is this within tolerances? Seems a bit too high to me.

 

[Skate323k137]

Depends what that voltage is used for. Most ICs run on 5v or 3.3v. If the -12 isn't used to run an IC it's probably fine. I come from arcade repair where we watch our 5v closely but not so much 12v. 12v is usually used for fans or audio amps with wide tolerances. 

 

[Riilu]

Well I'm probably gonna give up on this repair until i can either find a replacement board, or the tools necessary to actually find the problem. Probably some complex memory problem

 

[9166188]

Well I'm probably gonna give up on this repair until i can either find a replacement board, or the tools necessary to actually find the problem. Probably some complex memory problem

Happened to have the same issue after recap.  I fixed it.  Turns out there was a short between C8-C10 and a line next to these caps.  Wasn't visible to my eyes at all but my wire trace showed there was a short there.  I re-soldered them.  The short disappeared and it booted to normal.