Rescued what I thought was a Mac II

[ClassicGuyPhilly]

Hi all,

I've reconsidered doing the recap on the IIfx myself. I'd still like to learn to solder, and since I want an LC and IIci in my eventual collection, makes way more sense to recap those models after much practice and leave the IIfx to a professional.

After a few inquiries, I've located an area TV Repair Shop and talked with them. While the person I spoke with said a tech would need to check the board out in person, they have experience with such vintage computer work.

So, my scope of work starts with:
Logicboard
Battery Holder replacement x2
Tantalum capacitor replacement - C24 and C9

In for a penny, in for a pound, so I think makes sense to also hit any other soldering work that may be beneficial and proactive to preserve the machine.

Power Supply - I've found capacitor replacement kits (link below) for the GE and Delta Mac II power supplies, but none for a Sony model. I haven't taken apart my power supply yet, but if there are electrolytic capacitors in there, or anything else potentially suspect, IMO should replace. I also read on an Apple II thread that sometimes old capacitors may work in power supplies but may not consistently hold the proper voltage.

Video Card - I've also found a capacitor replacement kit for a Mac II video card, but not sure if that's for my Toby. But if there are components on the video card that should be replaced, fair game too.

https://console5.com/store/computer-cap-kits/mac-68k-cap-kits/mac-ii-series-cap-kits.html

Am I missing anything else?

Trying to do as much research as I can, but I'm still in way over my head with the restoration work.

I will probably wait to actually perform the work until later (need a monitor, KB, Mouse first), but I think getting a quote for the soldering SOW soon is a good move.

Thanks!

 

[Forrest]

I’ve used the capacitor replacement kit for my Atari 800XL from Console5 - the parts were high quality and correct. I would leave the capacitor replacement to a pro - it’s difficult to remove some of those parts because they are close to adjacent components and it wouldn’t be hard to permanently damage the board.

 

[joshc]

The PSU in these tends to be pretty robust, I have never bothered recapping one as they always worked for me. I am speaking from a small sample size (5 of them so far) but still, that's 100% and these are very old and not had any power supply issues. But I guess as you are paying someone to do the work for you, it may be worth getting it done anyway.

Do you need to supply capacitors if paying someone to do the work for you? Will they not supply the caps?

 

[Forrest]

If you’re paying a pro to replace the caps, battery holders then it’s not a bad idea to have the power supply checked and the system tested to insure it boots to the desktop.

 

[ClassicGuyPhilly]

Good feedback as usual guys thx!

Glad for the "let a pro do the IIfx work" agreement and prepare to test after work is done

Not sure if I need to supply capacitors but IMO probably good to at least specify exactly what is desired for replacement. I found https://recapamac.com.au/macintosh-iifx/ and the author says use below for C24 and C9

47µf 16V KEMET tantalum capacitors (T491D476K016AT)

I also found these for the battery holders

https://www.digikey.com/en/products/detail/6S-1-2AA/6S-1-2AA-ND/2077833

I found this YT on removing the PSU. Also mentions looking for RIFA capacitors which may explode and cause a serious odor problem?

I will take out the PSU and see what it looks like and blast it with air. Pictures to be forthcoming.

And just an editorial note. I'm chronicling all this so maybe my research and all the good info and advice from those on the thread may help future IIfx-ers.

 

[ClassicGuyPhilly]

Disgustingly gross PSU


After compressed air bath. Then vacuuming. Then brushing. Then more vacuuming. Then another air bath..




Didn't look too bad after the cleaning. To my untrained eye I did not see and capacitor leakage or RIFA capacitors, but as always appreciate a double check. Thanks all!

 

[dood]

Joined this board because of this thread. Keep going!

 

[joshc]

The SONY units in these did not use paper RIFA filters so you should be good to go. Beware that the fan in these is a bit noisy, it’s a very high airflow fan as it draws air through the entire machine to keep all the NuBus cards cool.

 

[ClassicGuyPhilly]

@joshc Thanks for the check as always. IMO the fan's noise is part of the experience of a vintage machine and adds to its character.

So for the followers of this thread, @dood has been my computing hero since college and taught me UNIX and much more!

 

[ClassicGuyPhilly]

I opened up both floppies today. The 800kb was rather disgusting, the 1.44mb actually wasn't too bad. I gave both a compressed air bath. I'm going to follow the procedure on this video to completely clean the 800kb, but need to procure some electonics grease (apparently I shouldn't use same stuff from my bicycles ;-) ) I think I'll see how the 1.44mb does without a full tear down.

 

[ClassicGuyPhilly]

Based on strong recommendation from @CC_333 I ordered some EM-30L grease

 

[oldmacuser]

Thanks for this post. I’ve been enjoying reading it!

 

[ClassicGuyPhilly]

Thanks for this post. I’ve been enjoying reading it!

Appreciate you following along on the journey, thanks!

 

[olePigeon]

I use EM-30L for the metal chassis & head worm gear, 3-1 oil for the head shaft, and silicon grease for the ejection motor gears. Plus a spritz of contact cleaner for all the connectors and switches. I don't know if those are the correct greases and oils, but they work well for me.

 

[ClassicGuyPhilly]

Thanks @olePigeon ! Have you (or anyone else) had to replace the first gear in the ejection motor? Was mentioned in the video from my prior post as a common failure point. If so, anyone 3D print them? Just covering all bases... grease arrived today so 800kb tear down is on the to-do list now.

 

[Juror22]

Have you (or anyone else) had to replace the first gear in the ejection motor?

Yes, people 3D print them, but I have had really good experience with the ones that are molded - they seem to be both a stronger and also a more accurate copy (the teeth of those gears are really small and they need to be accurately shaped to work right). When I refresh my floppy drives, I take out this gear and perform a mild bend test with it (if its not already broken) by putting just a little strain on the center of the gear. If it was going to fail, it usually fails at that time. I've had more than a few survive the test that I have not replaced and I have not had to go in and replace those at a later time. The ones that fail, generally snap easily and are pretty brittle (I keep a few replacements handy, just in case).

 

[ClassicGuyPhilly]

Great info thanks @Juror22. I will provide results of the gear integrity test and anything else notable from the upcoming floppy drive tear down