Mac Classic - will it ever run again!!

[stephen_usher]

Sounds like something in the PSU or maybe a dry joint on the high tension coil.

[rubber_jonnie]

Sounds like something in the PSU or maybe a dry joint on the high tension coil.

Could be, the caps did leak badly on this and it makes me wonder if it has seeped insidiously into parts it shouldn't be, though the 'scream' was coming from the internal speaker.

I don't think it is high tension, as it was preceded by an out of memory error, after which I rebooted, it seemed ok and then screamed. The picture remained fine at all times. Looks like it's coming apart again.

[rubber_jonnie]

Currently running it with the the HDD disconnected and booted from ROM to see how it goes.

[stephen_usher]

You can download the CD image here: http://www.lingula.org.uk/~steve/share/ ... 96_SSW.zip

The ".toast" file is effectively the same as a .iso file. Apparently you can just rename it and it'll work. Well, that's what the Internet says anyway. Even modern macOS understands what it is (CD image created from the Toast program) so does the right thing automatically.

[rubber_jonnie]

You can download the CD image here: http://www.lingula.org.uk/~steve/share/ ... 96_SSW.zip

The ".toast" file is effectively the same as a .iso file. Apparently you can just rename it and it'll work. Well, that's what the Internet says anyway. Even modern macOS understands what it is (CD image created from the Toast program) so does the right thing automatically.

Awesome, thank you sir. I'm familiar with toast, but boy has it been a long time since I used it!!

I'm currently booted to 6.0.8.L with the RAM expansion removed to see if it makes a difference. When I booted from ROM but left the RAM card in, it did fail, and now I'm wondering if any of the other associated components near the damaged one I sorted out also need looking at.

More testing to follow, with the SIMMs removed from the expansion card if I can't make it fail with it all removed.

[Tomswork]

@rubber_jonnie

Almost always caps on the analog board are getting old and all the connectors need to be reflowed and the flyback. The get heat and vibration cracks and the solder joints.

Tom

[rubber_jonnie]

@rubber_jonnie

Almost always caps on the analog board are getting old and all the connectors need to be reflowed and the flyback. The get heat and vibration cracks and the solder joints.

Tom

Whilst I don't disagree with that, I'm confident this isn't the problem, as I've already replaced the caps and reflowed. As I said, it wasn't the flyback screaming, but sound from the speaker due to a system crash, and the image was fine.

Also, I let the machine run overnight with no Memory card installed and it was fine, so I'm now trying it with the memory card in, but no SIMMs installed on the card.

I think it's a memory issue, and either something to do with the SIMMs and I didn't leave it on long enough for the problem to show previously, OR it's something to do with the connections to the memory card as it was before when IIRC it was R106 that was not happy.

I need to RUN for a while now to see if it's fine without the SIMMs, and if it is, then I need to look at how they connect through to the rest of the machine.

Given it takes some time for the problem to appear it is possible there is a thermal element involved as well.

[stephen_usher]

I hate intermittent faults.

[rubber_jonnie]

I hate intermittent faults.

Tell me about it, hence the 'one step at a time' approach to see if I can narrow down where it's at.

[rubber_jonnie]

Ok, so so far so good, no problems. If it continues to work as expected up to lunch time I may upgrade to System 7 and see how that goes, it says it's good with 2MB of RAM and that's what I have with even without the SIMMs.

If all good at the end of the day, then it would seem to be the SIMM side of things that is going wonky and I can dig into that.