blog:mac_iici_refurb

Apple Mac IIci - Refurb & Capacitor Replacement

This little Mac IIci has been in my collection for a while now; it's a pretty powerful little system:

  • Daystar 68040 Accelerator (compared to the stock 68030)
  • 64MB RAM
  • Radius Powercolour 24X Video
  • Farallon Ethernet

The audio has always been a bit quiet, and I thought I should get around to replacing the capacitors in the audio section, but I recently (July 2020) turned it on, and besides needing to install a new SCSI drive (used for parts a while ago!), I couldn't get any audio out of it at all, and getting a disk recognised was a pain.

I checked the battery, and it is still okay - I replaced it around 2015, so it should last a while long. But looking at several of the caps on the board, they show signs of failing, with 'wet' around their bases:

Urgh. That job has suddenly moved up the priority list.

Model: Daystar Digital Turbo 040 (rev 3) @ 33MHz (I believe!)

A list of capacitors and ratings is available on the 68k Mac Liberation Army wiki, but I'll list them here anyway:

Tantalum:

  • 11x 47uF, 16v
  • 2x 10uF, 16v

Electrolytic:

  • 3x 470uF, 16v
  • 1x 220uF, 16v

Some IIci boards vary, so there may be one or two less/more of the quantities listed. But those are the main ratings needed.

Next Steps

[Update July 26th 2020] - Ordered a set of replacement capacitors and waiting for their delivery.

Original capacitors still in place; some of them are showing clearly visible leakage:

Original caps removed:

Of the dozen or so capacitors removed, I lost a single solder pad on one of them, and I've had to scrape away some of the solder mask and bridge it to one leg of the capacitor - it's the right audio channel, near the 3.5mm stereo output jack.

Not my neatest work, but I found I was out of desolder braid when I came to start the work, so it's as good as it can be, based on the circumstances.

And to prove it works, here's a recording of the actual system powering up (albeit in 'death mode'):

I don't think I've ever heard it as clear as that! :-D

A weird thing happened however on reassembly of everything… (at least) one of the SIMM modules failed, resulting in the 'chimes of death' as heard above. I swapped them out with some spares and everything was happy again. Not sure what caused that, but the audio output remains clear as expected.

  • blog/mac_iici_refurb.txt
  • Last modified: 2020/07/30 16:01
  • by john