Expandable to 36MB RAM, the LC III was a big improvement on the 10MB RAM limit of the LC II. These “pizza box” Macs can still be found for reasonable prices and are a great starting point for someone looking to get into vintage Mac collecting.
If you have an LC III, and it hasn’t been recapped, it will need it. It is virtually guaranteed that the surface mount electrolytic capacitors will have leaked and will not be functioning within their specifications.
The Mac LC III power supply recapping guide can be found here.
The backwards cap
It has been known for at least a decade that the Macintosh LC III was released with an electrolytic capacitor installed around the wrong way, matching the also incorrect position of the screen printed ‘+’ on the board. The culprit, C22 is part of the -5V rail and has been the topic of many discussions amongst collectors.
So why have I never highlighted this before? In part because I’ve always objected to the sensationalistic way in which this information has been disseminated. Forums and enthusiast groups get filled with comments like “OMG, Apple made a mistake in their computer design, can you believe it?!”
Well frankly, yes I can. There are mistakes made in computer design and manufacture all the time, but the fact that Apple took absolutely zero steps to remedy the situation gives you an idea of what a non-issue this really is. I have yet to hear a single story where this rogue reversed capacitor has been responsible for any issues. I’m sure there are plenty of people looking for something to blame after a failed recapping, but in my experience, this capacitor is not your problem.
So why address it now?
While I never expected this to be the case, this site has arguably become the primary resource of recapping guides for vintage Macs, and a number of people for whom I have a great deal of respect have urged me to make this update. I think they are tired of telling people to reverse the polarity of C22, only to hear “if that’s the case, why isn’t it on Recap-a-Mac?”
Well now it is.
Replacement components
- 47µf 16V KEMET tantalum capacitors (T491D476K016AT)
- 100µf 6.3V KEMET tantalum capacitors (T491D107K006AT)
- 10µf 16V KEMET tantalum capacitors (T491B106K016AT)
Recapping guides
