The good news first, I got a working Macintosh SE booting from its old interal harddrive! Persistence paid off :).
I went ahead and replaced the two remaining capacitors in the power supply. But that did not change anything. The next thing was recapping the whole mainboard. If I remember...
Yes, it doesn't matter what disk I insert. As soon as it accesses it, the Mac reboots.
The 12V rail seems a bit weak. I have ordered in these 330uf 240 Volt capacitors that are still the old ones in the power supply and will replace them as well.
I took out the floppy drive again and found 6 electrolytic caps. Some measured a quite high resistance. Luckily I got some small capacitors here for Walkman repairs and swapped all of them out - same result.
There are two "large" capacitors left in the power supply that I have not yet replaced...
Tried it, I get the flashing icon. Same with just the HDD connected. But it can't boot off it. The reboot behaviour only starts when it attempts to boot from the floppy. My assumption is that it is rather boot process related. But can confirm as I have no other device to boot off.
Not sure how...
I think I can rule out the power supply. It has been recapped already and I measured the 5 volt rail on the (spinning) HD. It's at 5.06, the 12V is a bit low at 11.98.
The only other bootable device at hand would be an SCSI ZIP 100 drive. I got a USB version as well, but the OS images I dumped...
So to clarify - right now I can't boot at all. The harddrive is likely corrupted (it never booted from it). The machine booted to desktop one time from floppy but then hung. From then on it only rebooted when accessing the floppy. I hear a chimme, then see the mouse cursor but no happy mac icon...
Hi,
I picked up a poor Macintosh SE at the tip. The screen did not turn on but the issue was quickly indentified and fixes. One capacitor next to the high voltage generation was bulking up. After that it not only chimed but we had a working screen.
Now I am stuck with it being in a boot loop...
Does anyone have a list of capacitors required? I would just order them in and get started once I have them. Just have it assembled again and want to use it with mouse for now.
Hi Guys,
I finally got a Powerbook and it actually does work. The only setback is the not working trackpad.
The only work on it I have done so far is replacing the backup battery. My hopes were that this gets the trackpad working again as well. I have cleaned connectors etc but the trackpad...
Thanks Guys, under a strong magnifying lens and after unsoldering all of them I saw how the pads connect with the circuit. There was still that line left that lead into the pad. After scratching off a bit of the protective layer I was able to connect the negative side of the capacitor to it...
Hi Guys,
I finally got lucky and scored a Macintosh Classic in good shape. It got (of course) the checkerboard issue due to capacitor leakage. The board looks pretty clean but looking closer revealed that the capacitors close to the power connector leaked (C5, C6, C8, C9) . The one worst was C6...