Jump to content

Attempting to recap a Macintosh Classic Analog board and lost track

Recommended Posts

I'm attempting to recap my Mac Classic's analog board and seem to have lost track of what goes where.  I'm not recapping the whole board just yet, only the ones that were obviously bulging or leaking for the moment as they're the ones that were the most obvious and problematic.  I've managed to get most of them done, replacing one by one, but I got distracted and now I can't find the proper values for CP11 and CP31.

Link to post
Share on other sites
4 hours ago, LaPorta said:

There are different revisions with different caps. I ran into this as well. If you can give me the actual number of it, I can see if I have one.

The part number for the board is 630-0395.  I Tried using the 630-0525 (220v international) as a reference since that's the most commonly documented, but it didn't work. 


This isn't the first time I've run into an issue like this, where all the documentation for an American computer is for the international version of it.  Sometimes I'm lucky, and the two are somewhat interchangeable, and other times they're not.  PSUs are particularly annoying that way.  


If possible, and just to check my work (since it's non-functional), is it possible anyone has a list of all the capacitor values with locations for this model?  I tried some schematics I found online, but for the life of me I couldn't find CP31, and there appeared to be other missing bits as well.  The good news is that I haven't done any damage.  It's just as broken as when I got it.

Link to post
Share on other sites
On 5/13/2020 at 2:48 AM, dochilli said:

I have the same board (630-0395) and the values for it are in my above post.

Cp 31 is 1000mF, 6,3V, 85°C


On 5/13/2020 at 6:41 AM, superjer2000 said:

I thought I had posted this before but couldn't find the post.  I compiled this while recapping~6 or so Classic/Classic II 110V boards.

Classic Analog Boards.xlsx

Thank you both for this.  I'm going to go over the entire board now and see if I can't get this thing to finally work!

Link to post
Share on other sites

A sad update :-(


First I wanted to say thank you so much to everyone who has tried to help me.  However, I must regretfully report that this is not going to be a salvageable Macintosh after all.  The corrosion to the analog board was far more severe than I had originally thought.  Several components were loose, and many of the traces and pads are falling off the board.  But the final nail came when I discovered a bent pin on the back of the CRT.  In my clumsy attempt to bend it back into shape the tube cracked and a piece of glass broke off, rendering any potential repairs to the analog board meaningless.   Maybe I'll come back to this someday.  But for right now, it's a parts-machine.  


Its case and most of its innards are still in decent shape, so I'll probably salvage them for other computers.  


I still have an SE with a single failed capacitor on its analog board, along with a bad hard drive.  So now that computer will be able to live on instead.  


I haven't decided what to do with its floppy drive yet.  I still have my LC III that I'm repairing (I temporarily gave its drive to an SE for the moment), and the drives on my Mac II are a little mismatched.  So either would be a good candidate for a transplant.  


The motherboard could be perfectly fine for all I know.  I did recap and clean it.  Unfortunately, however, I have no way to test my work at the moment.  


As for the case, the upper center crew hole is completely shattered on the front part.  It looks to be some sort of corrosive damage that discolored the screw as well.  But structurally, and cosmetically, it should still be salvageable.  The back is a little yellowed and has a few scuffs, but is otherwise in good shape.  Who knows, maybe I'll find another beat-up old classic that could use a facelift.  Or I'll just sell the bits I don't use on eBay...


All and all, this has been kind of a sad day for me.  I was really looking forward to getting this old Classic up and running again.  

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...