Lucky IIx acquisition

[Kaa]

Definitely some impressive results!!! I'm looking forward to some nicer weather to try this out too.

 

[Mr SN]

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.

 

[LaPorta]

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.

 

[Mr SN]

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.  

 

[LaPorta]

Very nice job! I only knew because I had to do a very similar bypass on my II. Very interesting battery mod: I haven’t seen them done as cleanly as that.

 

[joshc]

This is awesome, you are building my dream classic Mac!

 

[Mr SN]

I had some progress - I have the motherboard recapped and soft power on/power off is all working.  The 40meg original HD still boots so transferred that to a SCSI2SD v5.1 and initially ran into corruption issues.  I thought maybe it was maybe an incompatibility, but it looks that I was hitting a Mode 32 corruption issue.  A fresh OS install seems to work wonders, all up and working fine with 7.5.5. The accelerator is a 50 mhz 030, and I noticed it was getting hot, so a made a quick mod to move air over the CPU. I glued a couple of magnets to a small fan, created a splitter off the HD Power and use that to power the fan.  I suppose I could have not split the power since I'm not going to be using a loud spinning disk.  

 

[joshc]

That fan must be very loud at that size? No way of doing a mod with a 120mm fan?

Looking good though, that thing is a beast!