The ComputerHobbyShop Web Blog for
#MARCHintosh 2025!

A Mac Plus Restoration Journey

I recently acquired a vintage Mac Plus from eBay, which I saw was unfortunately in a terribly rusted condition
both outside and later, as I was sure, also inside. But with some patience and effort, I managed to bring it back to life.

First Steps

1st I had a lot of cleaning up to do. I had bought this Mac Plus after seeing it was terribly rusted on the outside, and when
I took it apart, I saw what I had expected--it was also rusted inside due to the battery corrosion that had leaked acid down
and rusted the metal frame. Capacitor goo had also leaked onto the analog board and ran down to the bottom of the case.

I noticed the rust and corrosion in the auction pictures and
I knew it was the perfect challenge for #MARCHintosh 2025.

ComputerHobbyShop 2025 MARCHintosh Entry Mac Plus Case

It was time to work on the plastic case and the metal frame.

I started on the metal frame, which was the scariest looking of all the parts.

The frame is a support for analog board, also houses the floppy drive, and stabilizes the front of the Mac below the CRT.
See a picture of the frame before removing it from the case. Notice the big ugly fan that was held in by bailing wires!

To clear off the rust on the metal frame which supports the logic board, I used a wire wheel brush set.

After I cleaned, wire-brushed, painted the frame and let it dry, I put it in the Mac. It turned out really nice looking too.

Then it was time to work on the logic board...
... it was a mother board that no child could love, lol.

ComputerHobbyShop 2025 MARCHintosh Entry Mac Plus Project Logic Board

I cleaned the logic board with very hot water and a scrubbing brush, then I used used my
YTL-015 1500 Watt Hot Air Paint Drying Tool and applied 70% rubbing alcohol for a
second scrubbing, as that was all I had in the shop. I used my tool again to get it
totally dry and I stopped just short of watching the plastic parts start to smoke.

After I put it back together, I was eager to see how bad the componets were in a live power up test.

The Initial Problems After Cleaning It Up and The Reassembly

See below the analog board/power supply before cleaning it.

Even though I had cleaned everything, at 1st boot the Mac
would not ding or chime, nor show anything on screen.

I was not ready to replace the caps nor re-solder any cold joints just yet, so I had decided
to switch out the analog board with a known good power supply on a known good analog board.
Now when I booted the Mac, it started with a ding, (the Mac Plus diagnostic chime was a good sign).

ComputerHobbyShop 2025 MARCHintosh Entry Mac Plus Project Logic Board Boot Error 1

But if you zoom in, maybe you can see, it only showed the Happy Mac in a small box on the screen.

I had never seen the Happy Mac trapped in a small jail cell before. It was strange how it appeared like that,
because bad memory will typically act different, but since it did chime, this told me that maybe the memory
was not configured right as the image would not fill the screen, or progress booting further past a Happy Mac.

Here is a short video demonstrating what bad RAM can act like.

In the clip I mention video screens are a sign of bad RAM, but I later also got an error code "0F000D" too.
It was just not filmed when it happened and I could not get the error code to come back a 2nd time.

The Solution Was Getting Closer Now

So the logic board needed further inspection. Even though the 4 RAM chips had some green corrosion
on them before, I had earlier cleaned the contacts with a brush and they looked OK. Suspecting mismatched
RAM sizes, I decided to take out the board and looking again more closely with a magnifying glass, I saw that
the logic board revealed the R8 resistor was cut, but was not bent very far back, ... see the R8 zoom in below...

ComputerHobbyShop 2025 MARCHintosh Entry Mac Plus Project Logic Board R8 Cut

A cut R8 was signifying a 4 MB configuration had been attempted earlier. My suspecting mismatched RAM was
right on the mark, as I'm sure a 4 MB configuration had been attempted by a previous owner and so troubleshooting
and looking more closely, an exam of the RAM included two TM4256GU8 chips. The Copilot AI said
these were 256 kilobits each. I also found two Micron MB8C8024M-M8 chips, which were not easily
explained by the AI, but even with that information missing, I suspected these two chips were 1 MB each.

Since I only got a chime and a happy Mac, it could mean that the last person to work on this Mac did indeed mismatch
the RAM sizes. I replaced the two 256k chips with two known good 1 MB chips. Success! The Mac booted up and
displayed 4,096K, confirming an issue of mismatched RAM sizes. Now it works fully with 2 MB + adding 2 MBs more.

The Final Steps

Now all I need to do is recap the original analog board, and since this Mac was also without a working floppy drive,
I at least know it will boot from the Floppy EMU. After I recap the analog board, I'll remove the donor one I used
for diagnostics and install the recapped unit and test boot the Mac Plus with SCSI after also running diganostics too.

Final Thoughts

This project has been a labor of love, and I'm thrilled to share it here.
I'll create a video for this project soon and post it at @ComputerHobbyShop on YouTube.
I got this knowing it needed work and restoring, but it wasn't until after I got it that I saw just how bad a shape it was in.

I enjoyed working on this vintage Macintosh Plus computer. I really didn't expct that the logic board would
be able to work again. It was a true adventure, doing a surprise restore and preservation of a piece of computing history
made this retoration project a rewarding challenge. Stay tuned for more as the original analog board is recapped!

The AI made this project report easier with blog html suggestions, and I typed to the AI,
"Thanks, I'll use this Mac Plus Restoration for my 2025 #MARCHintosh entry."

The AI wrote back, "You're very welcome! It's exciting that your restoration project will be showcased as part of
#MARCHintosh--what a perfect fit for the community! Your dedication and passion for retro computing is inspiring,
and I'm sure your readers will love seeing the transformation of this Mac Plus. If there's anything else you'd like help
with, from blog ideas to additional restoration tips, just let me know. Happy #MARCHintosh!"

End Game Notes:

AI Compliments Are Nice, but they sadly don't pay my hosting costs,
so if you enjoyed this restoration, please take a look at another project.

Apple iMac Intel 2.4GHz Core 2 Duo 4GB RAM, 80GB HD, Lowest Price & A+ Certified!

Apple made this iMac with new features to work great & run fast.
It is clean and newly restored at my ComputerHobbyShop.

Make me an offer on eBay and you also get the satisfaction of
knowing you bought green earth-friendly hardware!

Buy Green Earth Refurbished from ComputerPro2000

Who is this Green Earth Eco-Friendly Seller?

The Best Green Earth-Friendly Refurbisher can be found at ComputerPro2000.com

For confidence in my auctions, see my A+ Rating.
ComputerPro2000 does A+ Certified Work for all our customers.

Click image to verify A+ Certification Comptia License # 54KC79TLWGF4Q6CX

It's smart to buy where A+ Certified is verified!

Besdies that, I never sell something unless it is a thing I loved using myself!

FedEx Home Delivery or UPS Ground or USPS Saver
(Which ever saves more $$ at the time I'll ship it to you).

Ships in a Well Padded Box
(International buyers will be billed
by the eBay Global Shipping Program)

Any offer you make helps make these restore projects work, so thanks for your support.

The ComputerHobbyShop Web Blog for#MARCHintosh 2025!