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.
Motherboard
Daystar 68040 Accelerator
Model: Daystar Digital Turbo 040 (rev 3) @ 33MHz (I believe!)
Radius PowerColour Video
Farallon Ethernet
Atto SCSI
Model: SiliconExpress IV (Fast/Wide SCSI-2)
Capacitor List
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.
Removing Failed Capacitors
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.
New Capacitors Fitted
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.
Testing
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!
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.