Hey, this is a different take on a project I was considering taking on! My main focus was to output color to a modern external display rather than provide grayscale to the internal one, but this still sounds very interesting, and I definitely don't have any engineering experience in my project.
I was hesitating about including an FPGA in my project, because I feel like it should be possible to go without it, and leaving it off would definitely lower the price. But more power to you if you have the resources to handle that. Any chance your SoM has an exposed HDMI port we can try and get working post-launch?
I acquired a Power Mac G4 with Sonnet upgrade for a very good price from eBay. Asked the seller to remove the handles which they did and it arrived in one piece!
The original speed was 400 MHz but with the Sonnet upgrade this will be higher now, I don't know the clock speed yet.
I did a quick power on test with monitor plugged in, chimes and displays video fine. I don't have any system discs that will work with it yet, but that's the next thing to sort. The machine does not have any drives so I am just working out my options for putting an SSD in here.
My plans for this machine are:
Full disassembly / tear down
Full clean of every part
Inspect PSU, make a judgement on recapping
Replace electrolytic capacitors on the logic board
Add a spinning disk of some sort
Find a Sonnet Tempo SATA card
Install OS 9 / OS X
Set up a file server
Install some games
Eventually find an internal Zip drive to add to it
You are probably talking about the keyboard ?
never had any issue with keys, only the front Apple Logo should be removed, as this is affected by the peroxide.
But as i am only using the vanish powder and not any strong peroxide, don't think it will be any problem in the end.
stickers and silkscreen letters are not affected in the process.
Bilbit is spot on - regardless of AB variant designation, your Mac Plus AB needs to say "International" for it to be able to be converted between 120v and 240v (see first pic below).
My 120v Mac Plus (which was made in California!) does say International on the AB, and FWIW the AB model number is also 630-0102 (with no letter designation after it - there were many) and alternate part number on other side of AB is 820-0107-D (yours probably says 820-0082-E). Mine was made by Capetronic (Taiwan) during 40th week of 1988, a couple of years after your 1986 board. I've attached a few pics below for interest.
There was an earlier thread from 2007 which compared a bunch of Mac Plus (and Mac 512k etc.) AB variants, which I can't find a link to but it was titled "Mac 128k ~ Plus Analog Board Analysis" (neither Google or 68kmla search can find it, but I kept a copy in Evernote, phew!).
In terms of diagnosis, I'd first start by making sure your transformer is setup right. Check its settings and use a multimeter to double check what mains voltage its feeding the Mac Plus. Maybe its not 120v after all?
Then make sure you have the correct fuse replacement. Even though you've a 120v machine, you need a 250v 2.5A fuse (specifically, according to my AB a normal blow UL fuse for 120v - I can see some of this marked in your AB pic). By comparison my International AB operating on 240v needs a 250v 1.6A Type T fuse, and jumper W12 removed. See pic below for this guidance from my Mac.
Assuming you have a multimeter, once the input voltage and fuse check out I'd then check diodes & look for one that may have failed as a short in the rectifier area CR23,24,25,26, then check the other diodes. R55 can also be an issue - but normally this fails open and just results in a blank screen, not a blown fuse. Also check for other shorts (e.g. due to sloppy re-soldering following a recap). Then I'd focus on other components in the mains voltage area.
That's all the ideas I have for now, but I'm sure others who've been at this more than me can offer more advice.
Do you have the original battery? If you do your best bet would be to re cell it, If not tbh I wouldn't worry about the battery, the 1x0 series will run just fine off just a AC adapter. The HDD is a bit more tricky as the 2.5" SCSI drives are very hard to come by, there is the SCSI2SD powerbook edition which will probably be your best bet
It might be the weekend before I have a chance to dig up the box of 1x0 series parts but I'll let you know once I have