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I honestly don't know - I'm not familiar with the LCD circuitry. There *are* caps on the panel but they're not so prone to leakage as on the 1xx PBs afaik. Others have recapped their Portable screens, but I'm not sure if it was to address contrast issues. I wish I could provide more certainty...

Ah ok. Do you know if the display (or the logic board) has been recapped?

Is this a suddenly new symptom? Is it consistent? My first thought is a bad connection, but would be good to know some additional details / context.

I have doubts 7 would make a difference, and likely will drag without enough RAM. I'm using 6.0.8, seems good. This might merit a look at some docs to see how the contrast is being controlled... I'm not sure what the control panel is doing exactly, but it might be discoverable looking at tech...

@imactheknife On mine it's very noticeable, the lowest end of the slider makes the display quite faint. FWIW I did see a difference in your video, but it was very minor - certainly should be more.

Seems very regular - is that something structural showing through?

If you're feeling adventurous you could try shorting some of the pins on the keyboard connector... I think to GND which is pin 1. I know if you do this on the Portable's keyboard connectors it boots the machine.

Hm, yeah ok. I grabbed your Kicad files from Bitbucket and took a look - verrrry helpful - thank you! What I'm seeing is confirming for me that my original plan of taking the original serial modem design and jamming inside isn't going to work lol - I shouldn't have a serial line driver in there...

OK, so after some trial and error, it seems at least one of the symptoms were unrelated to my board - the random-selection-of-things was actually due to the PB being on its side (for access), so, yeah. Still get some 'nonsense' in the terminal... which is actually the character I type plus...

Hey! I'm hoping someone is willing to share some insights for an issue I'm hitting with an internal PB 1xx NodeMCU (8266) wifi modem emulator board I'm fussing with... whenever the board is powered and connected internally, the PB acts possessed. I've got a pcb with the ESP, max3232 and...

That's my take on it... the PB is aware on the hardware level that a card is installed, and the internal port operates on the same channel as the external modem port, but you choose to use one or the other in the Powerbook control panel. But it's one or the other.

Does anyone have recap list for the ADP-17AB PSU? I'm looking specifically for the voltage rating of C303 (the smaller 47µF one on the output side) - the glue was covering the rating and proved impossible to remove without also removing the cap's label... i'm good on the other three.

It'll run without the diode: Schematics are here (for 140, but 145 is the same for the most part): Mainboard - http://bitsavers.org/pdf/apple/mac/powerbook/140/050-409_PB140.pdf Daughter board - http://bitsavers.org/pdf/apple/mac/powerbook/140/050-410_PB140.pdf Yeah this is going to be...

Right under the speaker - U3

No worries! Good luck!

They have little leads on them already that match up with the pads on the board. There are lots of good vids of how to solder them on - here's the first one I found, shows the general idea:

I would say no - far too big, physically. You're looking for something like this: https://www.digikey.ie/en/products/detail/würth-elektronik/865090168010/9836335 Edit: or if you're looking on Amazon, this...

Do you know the landing size (or footprint) of the cap?

Ha, nope... I just had similar symptoms when I had a grounding issue in a 140, so it sounds familiar. You're right about the diode originally being a zener and present for reverse polarity protection... I have a vague memory though of a non-zener replacement possibly allowing reverse leakage...

You can buy 6V caps, but they're super unusual. And not available afaik at this capacitance or form factor.