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Meanwhile I fitted appropriate-capacity tabbed AA cells (2000mAh) instead of the 4/3AA 1500mAh cells I was using - the actual measured capacity had been only 488mAh. Then I saw -13mA as the measured battery current, with the measured voltage being correct (9.4V) but jumping to 16.4V when...

As it turns out, that first controller board is faulty. I took apart the second battery and put its board onto the same new cells, and it seems to work perfectly. The utilities still say the memory is faulty and can’t be repaired, but charging and discharging seems to have calibrated it well...

I had the same thing happen - Portable drive spinning up and down repeatedly - it was sad because it was working, and had interesting data which I was about to copy off, but the drive suddenly made a loud clunk from the heads, and never worked again. I took a 40MB Connor drive from a Classic...

Cheers. Yes, one of the faults is a shimmering that affects the greyscale backgrounds (i.e. doesn’t affect black-on-white) which is perhaps capacitor-related. I think my bigger worry right now is my rebuilt battery (which I’m hoping to use in my 540c) - the readings were odd, especially current...

Thanks, umm… I don’t have a great photo but this first one shows the area where the contrast is uneven, noticeable on the upper part of the tartan background that someone had chosen. I’m pretty certain it’s the rear polariser film starting to break down. It still looks ok in a pure...

Your work is amazing - my reply was shown at the bottom of page 2 in my browser (Safari on iOS) and so I didn’t even notice the other pages! :o The power plug is brilliant, I almost regret that I was able to repair my power adapter. I especially like your battery bay cover and the display...

I was surprised to find my 520’s are intact! Can see them in the photo below near the display connectors (behind the upside-down bezel). I was very careful taking it apart and reassembling. My first task was to clean/restore the battery contacts, and I’ve re-celled a battery which seemed to be...

Yes - I’ve repaired several 100s, I honestly think they’re a little nicer to work with than all the other 1xx machines. No broken standoffs, no ripped-out display hinges. Slimmer casing with a few nice curves. The blacked-out screen is, in my experience, the caps near the trackball connector...

Thank you for taking the time to document your experiences. I’ve found it just now, because I’m just beginning my journey with a 512K board, or more correctly two 512K boards. One seems like it has a short… so I’ll check the resistor packs :) the other has the correct startup sound but produces...

When you said “tested in another fully working Powerbook 100”, did you mean you’ve tested the power adapter, or the RAM expansion? Or the hard drive? After the chime, there’s usually a RAM test (takes longer with more RAM installed, I have a machine here with 8MB total that takes about ten...

Haha, thanks :) Speaking of bodge (wires) - Possibly this is a good place to ask - some 100 logic boards (about half the boards I see) have various resistors added in pairs onto the VLSI chips and strung across other places as pull-downs to ground, but always the same places. Looks like it was...

Cheers, yes, I’d read that and can now confirm that’s my experience :) Sorry about what looks like a horrible mess how I’ve fitted the tantalums, but there are no shorts and the hot glue will prevent any movement. Meanwhile, here’s the next PB100 display I have to fix. I mentioned this above...

Well, what a job :D The frustration of stripping tiny bits of wire did not get the better of me… and I was rewarded with nice stable contrast compared to the MLCCs. No need to adjust the contrast as it ‘warms up’ now. Would have been so much easier if I could have ordered shorter tantalums from...

I second this; I use electrolytics on the logic board (the Wurth Electronik ones from Mouser) and haven’t had any problems. I’ve done six now. Actually I love the PowerBook 100; I’m so much more successful with those than I am with other failed PowerBooks. Especially the 20MB hard drives - a...

Love that resistor! Trust you’ve made a tidier job after you proved it worked ;) Excellent detail from SuperSVGA in this thread about how the comparator and op-amp should regulate the 5V, and interesting measurements from you, which I shall use to diagnose my Portable that’s self-resetting when...

I’ve removed the button and the resistor - the resistor by itself was 30kOhm :) a really dumb failure, but I had something similar in a Powerbook 100 where a 100k resistor turned into a 322k. This never happens in general low-power electronics so I expect it’s a one-off, a red herring to give me...

Of course, it’s not as simple as just putting in a 10k resistor - that seemed to make the problem even worse, i.e. only 0.3V ‘pulled up’ dropping to 0V with NMI pressed. My gut feeling is that a corroded via right in the middle of the ‘S2’ marking, near the switches/previously-leaked...