• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

New IIsi project - any tips?

JC8080

Well-known member
I recently picked up a IIsi as a project, all my other machines are earlier compact Macs, this is my first Mac II project. Before I dive into it I thought I'd ask if there are any things I should know about working on these machines.

The seller said when he turned the machine on the power LED lights up, but no other signs of life. He purchased a Plus and the IIsi came with it, he wasn't planning on keeping it so he didn't do any further troubleshooting. The battery did not leak, however all the caps have leaked, so I will be doing a full recap. I assume this is the cause of the machine not powering up. My plan is to clean the board up and look for any damaged traces from the leaking caps, and go from there. Is it common for leaking caps in these machines to damage the board? Between the cap goo and the dust stuck to it, it's really hard to see if there is any damage until I clean the board. The battery has been removed after I took the attached photo, I didn't want that ticking timebomb anywhere near it. Any general thoughts/tips as I start this project?

I currently don't have a monitor for the machine, I'm going to start looking locally, I'd rather not risk having one shipped. If I get the machine recapped before I get a monitor, should I be able to power it up and see signs of life, assuming the recap fixed it? Should I be able to hear a chime? I know I wouldn't be able to do any real troubleshooting until I get a monitor, it would just be nice to tell if my recap was successful, even if I don't have a monitor yet.

Thanks!
 

Attachments

  • PXL_20221023_215920798.jpg
    PXL_20221023_215920798.jpg
    3.5 MB · Views: 41

bibilit

Well-known member
The board and the PSU should have new caps, PSU is a bit tricky as is a soft power unit.

You can deal with a video converter and a LCD instead of the original CRT.

What is the pink part ?
 

3lectr1cPPC

Well-known member
+1 on the PSU. They’re awful. You will almost certainly have leaky through-hole and surface mount caps inside of it. Good luck.
 

JC8080

Well-known member
Oh very cool, I knew the 25mhz overclock mod was a thing and wanted to do that once I get it working, I hadn't looked closely enough to see someone already did it. The machine also has a NuBus adapter w/ FPU and an Apple 8*24 video card. The guy I bought it from said it had 4mb of RAM, but I just pulled a SIMM and it looks like a 4mb SIMM to me, so that would be 16mb total, though I couldn't find great info online.

The recapping will make a good fall/winter hibernation project, now that the nice PNW weather is gone. ☔
 

imactheknife

Well-known member
Sweet little machine! Got a Ethernet card in my se/30 with fpu socket so i pulled that and put in my iisi. Will get different card for se/30
 

Byte Knight

Well-known member
I currently don't have a monitor for the machine, I'm going to start looking locally, I'd rather not risk having one shipped. If I get the machine recapped before I get a monitor, should I be able to power it up and see signs of life, assuming the recap fixed it? Should I be able to hear a chime? I know I wouldn't be able to do any real troubleshooting until I get a monitor, it would just be nice to tell if my recap was successful, even if I don't have a monitor yet.
Yes, it should chime and the HD and disk drive should spin up, unless you have a break in the 12V rail like I did. You might check out my recent IIsi restoration here:
 

imactheknife

Well-known member
The power supply will be the fun one. Recapped logic board straight forward unless you have trace damage etc. the psu is nasty on these as you might find out. I recapped mine, it worked for a bit and died. So i bought a recapped online.
 

JC8080

Well-known member
Yes, it should chime and the HD and disk drive should spin up, unless you have a break in the 12V rail like I did. You might check out my recent IIsi restoration here:
Thanks, I'll check that out.
The power supply will be the fun one. Recapped logic board straight forward unless you have trace damage etc. the psu is nasty on these as you might find out. I recapped mine, it worked for a bit and died. So i bought a recapped online.
Thanks for the heads up, I'll check out Branchus Creations video on the IIsi PSU recap and see what I'm getting myself into.
 

JC8080

Well-known member
I did a thorough clean of the logic board with an alcohol bath and some scrubbing, it came out looking great. Based on a naked-eye assessment, I don't see any damaged traces, even around there the cap leakage was worst. 🤞

Things weren't so great on the back. Everything looked fine, except for the overclock oscillator someone with no skill installed previously. There was some corrosion around the solder joints, so I took a q-tip and some alcohol to clean it up, and wasn't pleased by what I saw. I'll let the photos speak for themselves. Maybe they used corrosive flux and didn't clean it afterwards? I grabbed my meter and the Bomarc schematic, and all the legs have continuity through to their destination, so I might have dodged disaster. I'm definitely afraid to try to re-flow those joints, I think it's probably better to leave them alone as long as they are working.
 

Attachments

  • Back 1.jpg
    Back 1.jpg
    2.5 MB · Views: 17
  • Back 2.jpg
    Back 2.jpg
    2 MB · Views: 15
  • Dirty.jpg
    Dirty.jpg
    3.9 MB · Views: 15
  • Clean.jpg
    Clean.jpg
    2.9 MB · Views: 15

rikerjoe

Member
I just finished a successful IIsi restoration. Fun and challenging project! Here are a few tidbits from my experience. Definitely, my Sony PSU needed recapping - it barfed its brown cap goo all over one side of the logic board and on the bottom case and all over itself, including the underside. Nasty! All cleaned up nicely with IPA for the logic board and PSU, and a good soaking in soapy water for the case. Recapping the PSU isn’t too terrible if you’ve done a through-hole recap or two and follow the PSU recap video by Branchus Creations. I removed a few of the other components in the PSU to clean the cap goo thoroughly. The daughter board in the PSU is crap and easily loses pads (ask how I know). The logic board recap isn’t a big deal - all SMD caps are the same and the two axial caps are the same. Check continuity on the +12V and -12V rails (I checked via the external floppy port). In my case, the PSU cap goo wicked through the connector and ate at the traces to the +12V (pin 1) and -12V (pin 8) rails, which required repair after removal of the connector from the logic board. Good luck!
 
Top