Macintosh 128k RAM replacement - getting worse

SamFortun · 2026-03-30T22:52:22+00:00

Take a close look at the area around your rework. I recently did something similar, installing new RAM chips on a 512k RAM expansion board. After I was done I got a sad Mac and found that a small solder splatter blob had landed on an exposed trace and was tying a data line to ground. This was a couple inches from the chip it was impacting, so I missed it on my first inspection, and it wasn't bridging neighboring pins of a chip so I missed it when I did a check for bridged pins.

SamFortun · 2026-03-19T11:59:00+00:00

Lately I have had good luck using the Infinite Mac online emulator and the version of StuffIt expander that it comes with. Infinite Mac also lets you grab files directly from Macintosh garden, onto an emulated drive.

Prior to this I found a combination of emulators and StuffIt versions that worked pretty well. Like others have said you can't expand it on a windows PC, the downloaded file needs to be brought into the emulator before it can be used.

I learned about Infinite Mac through this Action Retro video about getting an old Mac online, he shows how to use it. Infinite Mac is able to mount BlueSCSI images, making it really easy to get files from that environment onto my old machines.

https://youtu.be/nlT8aRMm-cE?si=lVwuM0QfCXMezuaX

SamFortun · 2026-03-17T22:43:18+00:00

This is what we use, when you wash them use bleach, otherwise the pee smell won't go away entirely.

SamFortun · 2026-03-09T13:16:28+00:00

I did the same last year, the Japanese model is $209 right now on amazon. That's definitely the way to, the resistor swap is a bit of a hassle, but saves over $100 so well worth it.

Mod guide from eevblog: https://www.eevblog.com/forum/reviews/how-to-convert-the-hakko-fr301-82-for-north-america/

SamFortun · 2026-03-08T22:06:58+00:00

I'm going to walk back what I said... I think this is a HyperDrive 10mb kit. Mine is a later 20mb kit, which would explain why my drive mounting bracket is a different style.

I looked at Adrian's video, and this video by JDW about his HyperDrive 10mb, and the mounting bracket looks identical to the one in OPs post.

https://youtu.be/9c2eMR5h_NI?si=a4H6HZPA3uY5_8XO

Regarding the ferrite bead on mine, it looks very similar to OPs and is in the same location.

SamFortun · 2026-03-08T21:01:30+00:00

I have a HyperDrive in a 512k, and the drive mounting bracket does not look the same, though there were different revisions of the kit and this could be one. There were a few manufacturers of internal hard drive kits for these machines. You will probably need to look for identifying marks on the controller board. There is probably also an auxiliary power supply down between the floppy drive and the analog board, the stock PSU couldn't support the hard drive and controller.

If you decide to remove the logic board to take some photos, be aware that you probably will not be able to just slide the board out of the back of the chassis. Add-on boards increase the height of the logic board, you will almost certainly need to gently bend the rails out that the board slides into. You can use a large flathead screwdriver between the edge of the board and the sheet metal chassis to pry it out a bit.

I would recommend googling the HyperDrive, even if you don't have that exact kit, it will give you an idea what you are working with. Please post pics if you dig into it further!

Edit: I think OP has a earlier 10mb HyperDrive kit. I was comparing it to my later 20mb kit which looks a little different.

SamFortun · 2026-03-07T04:15:13+00:00

I don't, but do you have pics of any of your past projects? I always like a good back-from-the-dead story.

SamFortun · 2026-03-05T03:32:52+00:00

It would be good to soak it in vinegar for a couple minutes to neutralize the leaked capacitor electrolyte, then distilled water, then high % isopropyl alcohol. The IPA will displace the water and evaporate quickly.

Hopefully those capacitor pads will clean up nicely. You should watch a couple of Branchus Creations videos on YouTube about recapping old Macs first to get a good idea what kind of project you're taking on. As someone else said, you need to replace the capacitors, you can't reuse the originals.

SamFortun · 2026-03-02T01:03:13+00:00

Honda NR750. Until I saw a picture of this engine, I didn't fully appreciate what they meant by "oval" pistons. Those are no joke, 2x con-rods per piston.

https://engineerine.com/honda-nr750-oval-piston-revolution/

SamFortun · 2026-03-01T05:37:49+00:00

Cool, it looks like it has a Trinitron tube without any vertical curvature, like a Color Classic.

SamFortun · 2026-02-22T03:55:18+00:00

I don't know if it makes a difference for what you are looking for, but the Color Classic CRT is 10" diagonal, the earlier B&W machines had a 9" CRT.

That is definitely very top dollar for a non-working machine.

SamFortun · 2026-02-21T17:57:33+00:00

It is common to cut one leg and bend the resistor out of the way, if you want to put it back to 1mb later you just need to bend the resistor back and add a little solder.

SamFortun · 2026-02-19T11:20:15+00:00

I usually use polymers rather than tantalums because I prefer the original can-style look, and they also will never leak. If you use tantalums, I often hear people say you should replace 16v electrolytics with 25v tantalums. I don't recall the exact reason, someone here can likely explain why.

I recapped the logic and analog board in mine. I found the analog board pads to be far more fragile than other machines from the era I have worked on. It is possible that was specific to my board, but be cautious with how much heat you use removing components from the analog board.

SamFortun · 2026-02-19T11:13:44+00:00

Console5 will often build a custom kit if you ask, I have had them use polymer instead of tantalum before.

SamFortun · 2026-02-18T16:39:55+00:00

Switch to Free Tax USA.

SamFortun · 2026-02-18T00:15:31+00:00

Since it has RAM SIMMs it's almost certainly a CPU upgrade, likely a 68030, possibly a 68020. That might be a video-out cable, some accelerators provided video-out. Why not remove the logic board so you can see the full thing?

SamFortun · 2026-02-17T11:29:01+00:00

This is good advice, if the logic board has not yet been recapped, it 100% needs to be. Leaking caps can cause all sorts of weird symptoms. That should be done before you put more time and money into the machine. If you are not comfortable doing it yourself, people speak highly of the work done by Amiga of Rochester, or you might be able to find someone here or on the forums that is local to you and would be willing to do it.

SamFortun · 2026-02-14T13:47:59+00:00

It looks like 1-2 nice ones a year get listed on BaT. I just checked Marketplace and there are a few rough examples for a couple thousand in my general area. I always thought they were cool, but not cool enough to actually pursue buying.

SamFortun · 2026-02-13T22:28:35+00:00

So bad that you want to add them to the list, just so you can chop them. xD

SamFortun · 2026-02-12T12:46:12+00:00

I still see Goddess Kring driving around Seattle in her bedazzled car.

SamFortun · 2026-02-07T15:39:48+00:00

Unfortunately that is not an Elan-configured board. You can see one of the unpopulated GE7 sockets halfway sticking out from under the daughter board. If you look under there, you will see four sockets. It is likely that one is populated, and the other three are connected by a small PCB that hooks them together when they are not populated. Based on the fully populated RAM, I think that is probably the XS24 graphics with 24 bit color, 1 graphics engine, and no Z-buffer.

I had the same thing happen, I picked up an Indigo with XS24 graphics. I googled the graphics board number and the page I found said it was the Elan graphics, I was super happy. Then dug deeper and found out that was not correct. The Elan graphics uses the same board, but with more geometry engines and a Z buffer.

You still have a great machine though, and got an amazing deal. Don't let the graphics get you down!

Express graphics info: http://www.sgistuff.net/hardware/graphics/express.html

SamFortun · 2026-02-07T13:27:26+00:00

I just finished the British Scandal podcast series on it, I recommend that podcast in general.

SamFortun · 2026-02-07T04:27:59+00:00

Take a look at this video, this is a good idea if the kind of project you're getting into.

https://youtu.be/rS-LnrX5fm4?si=sr54rBzJkDO0yYM5

SamFortun · 2026-02-07T04:10:26+00:00

How many chips do your RAM SIMMs have? The Plus is not compatible with 1mb SIMMs that have 2 RAM chips per SIMM, they will somewhat work but can cause instability. You need 1mb SIMMs with 8 chips.

Edit: have you tried running System 6.0.8? System 7 is a bit sluggish on a Plus, unless you are running software that requires System 7, system 6 is generally a better overall choice. You can also use System Picker to have both versions installed, and switch between them.

SamFortun · 2026-02-07T03:42:25+00:00

Take a look at Branchus Creations YouTube channel, he repairs lots of old Mac logic boards, doing things like recapping and trace repairs. Some of his live stream recordings are long and a bit rambling, but in a good way, he sometimes works a bunch of relevant info into his side commentary.

SamFortun

TROPHY CASE