Pre-emptive capacitor replacement...

[nater]

Hi,

This is my first time posting here... I've been a Mac user for a long time, and have a few classic systems in my collection that are running fine now, but I know that someday I'll have to replace failed capacitors in them. I would rather re-cap them pre-emptively than wait until they fail (and deal with that potential mess).

The systems I'd like to focus on right now are my Mac 128k, SE/30, and maybe my Color Classic (which currently has a Mystic motherboard in it).

I have a Weller soldering station, and while I have some experience soldering, it's been mostly small things and brief projects. Ideally whatever work I do, I'd like to get replacement capacitors that will last even longer than what came in these systems (so the next time I'll need to do this will be at least 20 years from now). I'm interested in replacing all the liquid/gel electrolytic capacitors if I can (motherboard, power supply, analog board, wherever they might be).

Is there a resource on the internet which has a list of the capacitors in these machines, and any suggested longer-life substitutes - such as tantalum polymer capacitors - when they can be used?

Thanks in advance for any help or tips!

 

[JRL]

Trag sells new SE/30 tantalum capacitor replacement sets.

http://68kmla.org/forums/viewtopic.php?f=4&t=4884

Info on replacing them is on the board.

 

[Osgeld]

and I suggest you do some practicing, weather its taking apart some old electro junk or going down to radio shack and buying some random caps and a perf board, soldering and desoldering is not hard, but there is a technique to it all which will make your life happier and your mac safer

 

[nater]

Thanks for the tips! I'll contact trag regarding the SE/30 caps.

However, that still leaves the Mac 128k, and capacitors in power supplies/analog boards in these compact Macs. I've read that until the late era Mac Plus, the power supplies were equipped with capacitors that weren't really up to the task... I've also read that there have been a lot of revisions to the components in the power supplies of the compact Macs from the 128k to the Plus, so am I correct in guessing that documentation on this topic is scattered? Should I just not worry about the components in the power supplies until they die?

 

[nater]

So I did a little more searching, and here are the motherboard capacitors used in a 128k:

33µF 16V, 2 pieces

4.7µF 35V, 1 piece

Got that info from here: http://retromaccast.ning.com/profiles/blogs/compact-mac-analog-board

He also lists the analog board components, which I found some other, older info on here: http://macfaq.org/plusanalogue.html and here: http://www.jagshouse.com/vertical.html

What are folks' opinions on doing pre-emptive replacement work on the analog board?

 

[joshc]

What are folks' opinions on doing pre-emptive replacement work on the analog board?

It's a must, really. Capacitors that are over 20 years old and very susceptible to heat will undoubtedly fail soon. You will find a copy of Larry Pina's Macintosh Repair & Upgrade Secrets book a very good investment - used copies are available from many sellers online. The appendix of this book lists all the components on the 128K/512K/Plus logicboard, analog board/CRT video board, and the SE analog board/CRT video board. Unfortunately it does not cover models after the SE.

I personally think it is a very wise decision to replace all capacitors - both electrolytic and ceramic, on the logicboard, analog board, CRT video board, and power supply. In theory, this should ensure trouble-free computing for another couple decades, providing other parts are in good working order and haven't had a stressful past.

Trag doesn't sell the capacitors you need for the analog board, video board and power supply. As such, you'll have to source these from a retailer such as Farnell, which I believe do supply the general public and not just businesses.

 

[nater]

Thanks for the confirmation that I should do the analog boards too. I've heard of "Macintosh Repair & Upgrade Secrets" - while Alibris has somone selling a new copy for $96.11, Amazon has a seller with a new copy for the low, low price of just $1,188.39. Wow. (I ordered a used copy for $20.)

My non-surface mount soldering skills should be pretty good (many years ago in high school I took a summer course in electronics that involved a lot of soldering, both practice on junk electronics and a couple of kit projects). It's the surface mount stuff that I'll have to take extra care with.

 

[joshc]

Thanks for the confirmation that I should do the analog boards too. I've heard of "Macintosh Repair & Upgrade Secrets" - while Alibris has somone selling a new copy for $96.11, Amazon has a seller with a new copy for the low, low price of just $1,188.39. Wow. (I ordered a used copy for $20.)
My non-surface mount soldering skills should be pretty good (many years ago in high school I took a summer course in electronics that involved a lot of soldering, both practice on junk electronics and a couple of kit projects). It's the surface mount stuff that I'll have to take extra care with.

You will find the book absolutely invaluable, as it is still the only source of detailed information on the specific repairs and upgrades on 128K/512K/Plus/SE Macintoshes. You are in a very similar situation to myself. I have an SE to recap, and I also have a IIci which needs new capacitors (I already have the components for it), but unfortunately since its surface mount it will require a bit more skill. I'm also still searching for a good temperature-controlled soldering iron to make the work easier.