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Not that it helps, but I received two batteries from the USA at long last, from a friend visiting me in NZ. These batteries came with two 520c machines that I bought off eBay but - in a long and convoluted story - couldn’t be sent to me because of the batteries, so I had them sent to my friend...

Oh - lol, absolutely agree - I didn’t mean a prefabricated holder, I meant to design spaces for the cells into the 3D-printed part, with terminal plates or - as I use - CAT5 wires stripped and threaded through holes to make contact. Non-tabbed cells are a lot cheaper and easier to get here than...

Ahh you beat me to it, I’ve been looking forward to trying that :D well done! Now we just have to design the battery holders within the casing. So, two groups of five 2500mAh cells in parallel. I’m a little surprised as I couldn’t get a 100 to run on five cells (needed six - 7.2V) but the 100...

Amazing - thanks for providing the link. Hard to believe the monitor/analog board was capable of handling an increased resolution/increased frequency all along! Back at that time, it would really have helped, as some newer software assumed a 640x480 display. I guess that Apple had strict rules...

This is a really good idea - well done! :) Many of the original switches seem to have corroded contacts from battery leakage. I hadn’t found that switch size.

I’m in NZ and I’ve been working on something similar, I use 3D-printing to solve lots of problems like this. I made a battery for the Powerbook 100 that uses CAT5-wires (the stripped wires from the cable) to thread through holes in springy parts of the design. So, you can join the dots on what I...

Cheesestraws is absolutely right - I do the wash in hot soapy water (with dishwashing liquid) first, scrubbing with a toothbrush, and then after blow-drying, I use IPA to rinse. I haven’t had any problems with speakers or flybacks - I’m just careful not to touch the speaker when it’s wet. When...

Yes - replacing the SWIM chip restored the correct operation of the floppy drive in the backlit Portable that I was working on :)

I replaced the 6522 twice more, using chips taken from old 512K boards that don’t work for other reasons. I’ve installed a 40-pin socket so the 6522 is easy to swap. Both of the older 6522s produce a new result - the startup tone sounds (yay!), and then the screen is blank (boo!). Floppy drive...

Yep, and then replace the optocoupler again. Voltages will probably be back to normal - for a while. Cleaning the analog board in hot soapy water does seem like a good idea, if you’ve had that much gunk floating around that a diode leg was corroded off.

Good stuff. One thing to think about - when you replace the optocoupler - I think they are possible to damage with soldering temperature, and I think that’s why they are socketed in the original Mac/Mac Plus analog board. So, the last optocoupler I fitted to a Classic, I took a row of pin...

So you heard a bang, but you’ve still got some voltage produced? Check the two 0.1uF capacitors that are wired across the AC input - they are near the metal frame. They often split/explode. If anything else has gone bang, it seems impossible that it would turn on at all. To fix the low voltage...

It feels like if there was one cracked via (corroded via from capacitor leakage perhaps), then there’s probably another, this time from the SWIM? I really appreciate your thorough report of the sound and boot problems and their cause, I feel I may be facing something similar one day.

I’ve now replaced the 6522 - which has changed the display to that below (please disregard the 512K Mac case/analog board used for testing - this is a Plus logic board producing this display) It’s now bars alternated with slightly-shorter bars below - I don’t know what it means, does anyone...

Luckily no-one commented on the filthy condition of the Mac 512K that I was working on - it’s finished now :) I treated the case with water+peroxide+sunlight, but then I also gave it a light spray-painting of a carefully-matched beige colour, so with a bit of luck, it should stay this way...

It’s been a while but I think it’s the edge closest to the display that pops free first. I recall they are robust (the white plastic stabiliser is not brittle). Use something like a blunt knife to pry the edge of the keycap upwards.

Best of luck! I eventually reached a situation that I was happy with. Several further learnings; 1 - I recommend arranging a longer cable, for example an external drive cable, to avoid the EMI interference problem (from the Mac’s screen) while making adjustments with the drive’s top cover...

I’ve learned a few things today, but the most stark was the truth in the above. I learned that if I click Format Disk in the test program, it should immediately start formatting - if it returns to track 0 and throws an error, then starts formatting on a second click of Format Disk, that means...

Funny; we’ve both been dealing with Powerbook 500-series at the same time, and now, we’re both dealing with 400K drives on the same day… :) State of play with mine is that, after much adjustment of the track-0 sensor, I can get it to display a Happy Mac (when a boot disk is inserted) but then a...

Nice work :) With regard to the video loss (I had that recently too), it really is often caused by the pins of the analog board connector (for the logic board cable) as people say - one of the pins stands separate from the others, is often missed in resoldering, and that’s the video signal. I...