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Hmmm... It would help if there was documentation on the return values. Most of the tests on my IIci return nothing it seems. The critical memory test does fail but I'm not sure what the error code actually is. Is it the address? Is it the value it read? Who knows? There doesn't seem to be any...

Ooo... That's good. I take it that it's the printer port 9600, 8-n-1?

Is there a diag ROM for the Mac which outputs information via the serial port as it tests hardware as other platforms have? I really could do with something which checks the hardware before the display and NuBus are initialised on the IIci. Something like a minimal RAM test and basic hardware...

Oh! That's a mess! (I'd get that battery out and wash the board under the tap.) What would you like to do now? Do you want to harvest the chip yourself or would you like me to buy your IIsi motherboard?

I have a sick IIci motherboard which has a half dead RBV chip. Would anyone, preferably in the UK or Europe, have a recovered working chip I could purchase?

Bother! All it says is that thr RBV signals the MPU that it wants a memory transfer but doesn't give details and the Bomarc schematics are, as usual, less than useful.

Thanks

I'm currently trying to diagnose a Mac IIci which has been passed from retro-enthusiast to retro-enthusiast to try to repair it. Previous people have fixed the battery damage to the point where it will bong and then turn the display black and finally crash as soon as the NuBUS select line goes...

Well, I guessed that it was probably a connection issue, so reflowed the pads on the SIMMs, and the problem has gone away entirely. The PCB is probably slightly thinner than the original SIMMs and so the contact between the pad and the socket wasn't good enough.

OK. I decided to look at A9 (pin 19) on the SIMMs, just to see what it looked like on the 'scope, as this is the address line the 4MB uses and the 1MB ones don't. Fitted the SIMMs into bank B again, put the probe on the pin, switched on... And happy chime. *sigh* It's having a laugh. It saw me...

Indeed, the option 2 was merely a test to see if they worked at all, which they do (at least the lower 1MB), so it's not the contacts in the slots. I was surprised that it did actually POST to be honest. Electrolube EML already used on the slots. I have no other 4MB SIMMs to test with. The...

I've just bought a set of four 4MB SIMMs from eBay and I'm getting the following symptoms: All four SIMMs in either RAM bank (if in bank B then with known working SIMMs in bank A): Fails POST: corrupt display. Replace one known good 1MB SIMM with any one of the new 4MB ones: Happy chime...

Indeed, 7.5V is the correct charging voltage. If you check on the label on the battery you'll see this listed. All I can suggest is that there's a fault in the battery generating an internal short, possibly buckled plates.

I've a v6 in an SE/30 and it's fine. Just don't turn on the SCSI2 stuff. As for the original poster's question about speed, no, the SE/30 won't take advantage of it. The NCR 53C80 maxes out at a theoretical 1.5MB/s but in reality is about 1.2MB/s.

From that image Q21 looks cooked. I had that on my machine when the +12V line got overloaded.

The SD2SCSI (v5.1) works in all my other classic Macs as it is, without any configuration changes and with the same SD card and filesystem, so it's unlikely to be an incompatibility. I've run out of Mac compatible SCSI drives now as they all seem to have died with age.

As previously stated the device I'm testing with works fine on another SE/30 and Mac Portable. It's a SD2SCSI and the filesystem was created on the other SE/30. The drive was just moved from one machine to the other.   By one drive I thought you meant one drive connected at the time rather...

No, just the one.

I could try getting it off the board, I do have a hot air rework station, but any such work is risky, so I'd leave that as a last resort. I'd install a socket afterwards if I did remove it though.