Macintosh IIfx Project

[Saint Pablo]

Hey everyone! This is my first post here on these forums. Exciting to see a non-Discord method of interest and hobby sharing in 2026.

Anyways - this is my project for however long it takes me.

I bought this Macintosh IIfx on eBay for ~$400.

Here are a couple of first thoughts:

• Case seems to be in fairly bad shape - multiple cracks + broken clips + the inside metal shroud is rusty af.
• Motherboard luckily seems to be in near perfect condition, with the exception of a few broken component clips for (what I think is) the HDD enclosure.
• There are OBVIOUSLY damaged RAM SIMMs in this machine.

I bought this listing in particular: https://www.ebay.com/itm/407183257267

The description mentioned the hard drive enclosure was loose in the case, which may have caused damage to the components inside. However, from the listing pictures there didn't seem to be any obvious component damage... yet! That changed when it was mailed to me, it seems.

As I said, luckily the board itself didn't seem to take any damage, but I have at least 3 RAM SIMMs that need to be replaced. No obvious capacitor leakage, and also it looks like all batteries have been removed.

I'd love y'all's initial thoughts on this project. Where should I start, and where should I watch to score replacement components? I know the RAM for this particular model tends to be difficult to come across...

Any help/direction/thoughts in general y'all can offer would be greatly appreciated.

 

[eric]

Hopefully get a partial refund for the shipping damage - those RAM sticks are going to be expensive/hard to replace. I'm starting on my own IIfx build as I've finally got all the parts I need to start (I should start a thread too!)

Also, welcome! We have Discord too but you can be on one or the other or both, we don't judge!

 

[Saint Pablo]

Hopefully get a partial refund for the shipping damage - those RAM sticks are going to be expensive/hard to replace. I'm starting on my own IIfx build as I've finally got all the parts I need to start (I should start a thread too!)

Also, welcome! We have Discord too but you can be on one or the other or both, we don't judge!

Please do! I was not alive when this machine came out - and I only recently started using Apple computers maybe 5 years ago. But I have strong interest in computer history and am technically skilled!

Anything you can share - or I can learn from would be most appreciated!

 

[jmacz]

The capacitors need to be replaced. Even if they appear fine, you’ll know when you remove them because you’ll smell the fishy odor. Those 16V 47uF cans always leak. And the photo is blurry but it does look like you have trace wear near the power button — the dark spots on the trace that run there. I’ve seen that on numerous Mac IIfx’s (and II/IIx). So you definitely need to replace those.

You also need to replace the C1 tantalum capacitor. Apple shipped those rated at 16V and it’s known now that for these tantalum’s, they need to be rated 2x the voltage.. that C1 cap is on 12V and so you need at least a 25V tantalum to replace it. That C1 is notorious for blowing up and leaving a crater on the logic board as well as taking out some of the nearby components.

Lastly, it looks like you might be able to repair the RAM. At least from the picture, I don’t see any pads completely gone. You may be able to use flux and hot air to remove the chips that got hit, bend the pins back, fix any pads or add bodge wires for the pads that are lifted, and then resolder the chips. Given these are harder to replace, I‘d try to fix those. I wouldn’t give up on them yet.

The power supply I have found to usually be good in the IIfx but they will need a recap at some point as well. But definitely be careful in there if you haven’t messed around inside PSUs before.

Goodluck!

 

[Trash80toG4]

YOWCH! It looks like whatever kinda cage rattling around loose in there was for a 3.5" drive and kept caged under the peripherals tray by its supports? The cards look to be in great shape and an interesting lot, especially if you're into music.

Welcome from a fellow forum dweller! Sometimes I feel like I'm living under a rock here, but Eric's weekly Discord updates help a lot.