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Lucky IIx acquisition


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I picked up a IIx for really cheap, less then $100 on ebay. I've been looking to do a Mac IIx restore as I have a spare IIx motherboard given to me a long time ago that seemed to be in pretty good shape.  The IIx I got was very yellowed so I wasn't sure if the mac had been stored well or not. However, the best part was when I opened it up. Aside from the vintage original 40mb Apple drive, hidden under the drive tray is what looks to be a 50mhz Daystar 030 accelerator! I seem to recall that those older macs used special RAM for going high density.  The system was pretty clean on the inside and corrosion on the board does not look too bad either. You can tell the caps have leaked some, but not really bad.  From what I can tell, it does not look like anyone has been inside doing anything with the system, everything seemed "tight" in what you expect when cables and crews have been in place for years. One odd thing, I removed the batteries and one was dead and the other had 3.6v still (the batteries share the same lot number).

 

I did not try to power it on yet.  I'll give both of my IIx motherboards a power on test before I recap.  That's going to have to wait for a future weekend.  But I feel pretty lucky with this find!

IMG_2518.thumb.jpg.756bdfc96a3e940e64b5e5101048fb85.jpg\

IMG_2520.thumb.jpg.2c5da13e5c058cc722af6d3d89fcc0be.jpg

IMG_2523.thumb.jpg.2189541cfc93d9d5257dd371c5ef4fb9.jpg

 

IMG_2532.thumb.jpg.72040ff32b4af771eb047c570b13f464.jpg

IMG_2540.thumb.jpg.7dd63db27df59ab7cacb7e110290a54b.jpg

IMG_2541.thumb.jpg.d09f934d17e3556c70995030e91eb40d.jpg

998777660_IMG_2557(Edited)(Large).thumb.jpg.6774fb45b89b605fcf483784bfe4693c.jpg

 

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Nice.  That's the early IIx upgrade, before the PowerCache card with adapters became standard for Daystar.   With the giant cache card on top.

 

Very cool and at least a little rare.

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1 hour ago, Byrd said:

Nice score, it's amazing the seller didn't put that massive board in the description.

 

Is this accelerator also interchangeable in the SE/30, based on the PDS extender?

Those boards plugs directly into the CPU and FPU socket, those PDS extenders are just custom connectors for the cache board that sit on top of the accelerator board. The problem with boards that plug directly into the sockets is that every Apple model has different placements of the CPU and FPU and there are other things on the motherboard that get in the way. That is why there are so many Daystar adapters for macs just like there are so many Applied engineering 040 models.

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2 hours ago, Fizzbinn said:

Curious, what’s the edge connector on the upgrade board next to the front of case for? It loooks like it’s still accessible with the cache board installed?

Yes, if you look at the 3rd picture above, you can see it is still exposed.  Maybe it is used for QA testing? 

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I had some spare time today, so I took out the motherboard and cleaned it.  I think I have identified a few chips that show the most corrosion, red arrows pointing to them. Now I just need to figure out what they are. 

After the cleaned image is a post clean, followed by the Mac IIx board I got some time ago waiting in the wings for this project - just in case.

MacIIx-ICs.thumb.jpg.5709d1df26bb30d311435b349e76da6d.jpg

Pre-Clean.thumb.jpg.ed009ca2e8895af4cdbdb056ce7136cd.jpg

OtherIIx.thumb.jpg.01225f406f74572a7337dd908b47475f.jpg

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1 hour ago, Mr SN said:
3 hours ago, Fizzbinn said:

 

Yes, if you look at the 3rd picture above, you can see it is still exposed.  Maybe it is used for QA testing

This is where the XCI backplane connects. This would allow Nubus cards that had the appropriate backplane connection to talk directly to the accelerators 50MHz bus.

I think there was only ever only a single SCSI card that implemented this feature. Not sure if there exist any other Nubus cards that used the XCI bus.

Edited by Bolle
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This is a very nice find!

 

If you need any parts, let me know, as I have a spare IIx board which most likely doesn't work, but may nevertheless be useful to you if you need extra chips or anything, plus a PSU in case yours don't work.

 

c

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That’s a great find. Enjoy the IIx! It’s one of the prizes of my collection. When my wife threatens me with getting rid of my old Macs, I tell her she’ll have to pry the IIx, IIci and Quadra 700 out of my cold, dead hands (by that point, I guess my arms would be pretty full).

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So I tried to power on the MB, no go.  However, a friend pointed out something about the RAM.  It looks like they used DIP ram chips instead of surface mount chips.  And I hadn't noticed at first, the ram is actually Apple Ram (or made for Apple).  When looking even closer, there are a lot of imperfections, hand crafted in small batches :p  These must be real early ram simms from Apple, 120ns even.

 

 IMG_2655.thumb.jpg.92dbecaae3bd84c28ba93e654d8206dd.jpg 

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IMG_2652.thumb.jpg.61a34ce6aa8f656147068014c6d14032.jpg

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  • 2 weeks later...

Today was all about Retrobrite.  See the before and after below.  I am still working on the MB, I have recapped, rel-flowed a few suspect chips, and it will not power on with the power button.  If I use the technique with a battery to force a power on, it will power on with a discord. I tried several different sets of SIMMs to see if it is RAM.  Still something wrong.  It will power off with the button!

 

Below is pre-retro with the solution on it. 

IMG_2752.thumb.jpg.2dfea9ba6bfa627cb537bbd0860e8a90.jpg

Here it is 5 hours later 

IMG_2773.thumb.jpg.b51bd8ca33f6672afaab79f200bfef1a.jpg

Edited by Mr SN
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1 hour ago, krishnadraws said:

Impressive! A night and day difference! What method of Retrobrite did you use?

@LaPorta I read quite a bit about this and spent some time on YouTube trying to figure out what might be best. Even one guy who said maybe you don't want to do it!  Anyway, instead of making my own mixture, I found that you could order a pre-made liquid of hydrogen peroxide with a reactive agent in it already. https://www.amazon.com/gp/product/B0002Z916W/   I used a paint brush and painted on a good thick coat (as best I could) and then put it inside a gigantic ziplock bag.  I have been literally waiting for three weeks for a nice sunny weekend and finally got one.  I did do a precleaning of the case before painting on too.  I'm very happy with the results :) 

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  • 2 weeks later...

This weekend I worked a bit on the system and finished recapping.  The system will not power on using the MB button or keyboard.  If I use a battery and short the pins on the PSU, it will turn on, chime and boot:) 

 

Here it is booting, have the sound on for a treat.  First time it has booted since 2000 (according to the most recent modified time on a file).

 

https://youtu.be/COLayTvlIQ0

 

The system will power off when I select Shut Down, or if I press the MB button.  So I still need to figure why it won't turn on via the switch, but will power off.

 

 

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Almost certainly a rotten trace in the soft power circuit. Look up the Macintosh II power circuit via Google: it is well documented, and many good illustrations are available to help you backtrack and buzz out the traces. They were probably eaten by electrolyte. Much of that circuit runs through the areas that you indicated with your red arrows in previous photos.

Edited by LaPorta
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22 hours ago, LaPorta said:

Almost certainly a rotten trace in the soft power circuit. Look up the Macintosh II power circuit via Google: it is well documented, and many good illustrations are available to help you backtrack and buzz out the traces. They were probably eaten by electrolyte. Much of that circuit runs through the areas that you indicated with your red arrows in previous photos.

LaPorta - Thanks for the encouragement :)I tested the traces for continuity and found that SW1 trace did not connect to L4. Fixing it on the backside looked like the easiest thing to do, so with that done, the system works as expected. Power on via keyboard and switch in the back.  Pictures below.  I also did a battery mod where I use CR2032s instead of the PITA 1/2 AA that it came with.  The CR2032s are also a lot less likely to leak.  

 

BrokenTrace.thumb.jpeg.2e9f57df1f8903113bebe20089cbd48a.jpeg

TraceFix.thumb.jpeg.c19ec2afa08f00a0d9527a4bc7d0c4f1.jpeg

Battery.jpeg.1d477a52dbf68dffa11808dc356f3d0a.jpeg

Edited by Mr SN
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