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Hello all,

 

Another restore thread (I like following these for other people, so I hope you do too)

 

Picked up a Mac Classic (1) from craigslist for $40 (they were asking $100, but accepted my offer right away, worth it to haggle :) - untested, dirty, yellow:

large.00p0p_9hMwLRznKkS_0oo0ii_1200x900.jpg.6fd52c238220f41c5f15c2e9665289c0.jpg

 

Had some interesting stickers/post it note (that must have been on there for 20 years, seems "original" and survived all this time lol)

You can see too how yellow/dirty/discolored the case is here too.

large.IMG_20200715_204109.jpg.a563e909d9f37842412e255ccc8bd074.jpglarge.IMG_20200715_204112.jpg.2abfb1e86036a56794c0e0e1cf490f9d.jpglarge.IMG_20200715_204118.jpg.d9c648ba1d66a081f413af0d99fdae69.jpg
 

Inside was "ok" lots of dirt in the fan, but just a bit everywhere else.

large.MVIMG_20200715_204444.jpg.e7afefe98e7c2415dafff6a083c906a7.jpglarge.IMG_20200715_204500.jpg.4e102af57f6381b96878cda1021bd071.jpg

 

Motherboard has expected cap leakage - along with a memory riser card which I've never seen in person, neat!

large.IMG_20200715_204831.jpg.0d046a500cbbcf7ae35227705fdb92c6.jpglarge.IMG_20200715_204703.jpg.b232c7fccfc0161c0f3556cfb4b7b68c.jpg

 

I cleaned the motherboard with 99% IPA - let dry and booted up, but had some really "weird" results!

 

  • First power on i heard some crackle from the speaker, but nothing. Flipped the switch a few times, same thing.
  • Then I left it on for a second and all of a sudden the HDD spun up (scaring the crap out of me)
  • Then I see a faint checker board pattern
  • Then a "soft" reboot
  • Then the normal screen but "wavy" eg, the left/right side of the screen was waving in and out
  • The screen got brighter and brighter as time went on, then I got the question mark
  • As time went on the waves slowed and stopped.
  • Internal fan randomly started after a few minutes, again startling me!

 

My assumption is the analog board needs a recap. Something probably got warm enough to work and eventually was able to boot up.

 

large.IMG_20200715_220046.jpg.4291cfaa31e590b5003b10fe6e0c868a.jpg

 

Next Steps:

  • Recap Motherboard
  • Recap Analog board
  • Service floppy (wont eject)
  • Find a solution for HDD, it sounds like it's on it's last legs
  • Clean outside and try my 40% bottle of hair product method

 

I can say after working on the CC and SE/30 the past week, the insides of the Classic 1 are much easier to work with.

 

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Caps Removed very cleanly from board. Used hot air gun. Hard to not heat the plastic power adapter on the motherboard. Also retinned a leg on the Y1 that was very dark. Still need to pull Analog board out to get stock of caps needed for it.

 

Might as well service the floppy drive tonight too - ~5 superficial rust spots on it, maybe some cap leakage, cleaning up nicely though.

 

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I found that a good way to protect the plastic connectors and components is to cover them liberally with aluminum foil. A very good insulator for the heat (it is metal, but it deflects the air and won't get too hot in and of itself).

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Analog board issue for sure. 

 

Time for new caps and diodes at least. 

 

Price is is fair for the setup

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Is there a list of the caps needed for the analog board? There are so many on the board!

 

Console5 has a kit, but doesn't list what is included https://console5.com/store/macintosh-classic-and-classic-ii-analog-pcb-cap-kit-for-p-n-630-0525.html

 

Branchus Creations has a video on it, though it's for the international version.

 

(Also if the boards are the same as the classic II I can test everything in my II to rule things in/out.)

 

@LaPorta good idea - I did put some heat tape on there, but not enough i guess. Very minor discoloration, but will try your method next time, or a combination!

Edited by erichelgeson

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I’ll send you a copy of my Mouser part list. Be forewarned: it appears that 2-3 of the caps changed over time (not just ratings, but whether they are there or not) depending on the analog board revision. Logic board is almost the same (though there were different ROM size revisions).

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+1 to LaPorta's note – there are two revisions of Classic AB, and I used this helpful diagram (from the very useful "Technical Procedures Macintosh Family") to figure out which was which:

image.thumb.png.27c43529741a9b9dbd80bd1329bdda05.png

Welcome to Classic gang gang! These are so, so much easier to work on than SEs and SE/30s. Dare I say these are the ultimate compact Macs because of their simplicity.

Edited by rplacd

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Thanks! Interesting diagram. My yoke cable is A, has the "square" component next to it (not sure what it is) but has an Oval Hole? So I'm guessing A, but that oval hole is throwing me off :D

 

It says:

> Note: There are two versions of the Macintosh Classic power/sweep board: Rev A and Rev B. These two power/sweep boards are functionally equivalent but are not interchangeable. The Macintosh Classic II always contains the Rev B board.

 

So if my Classic 1 is indeed an A - I will not be able to test it with my Classic 2's AB.

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8 hours ago, erichelgeson said:

So if my Classic 1 is indeed an A - I will not be able to test it with my Classic 2's AB.

Not necessarily – the power connectors on the physical AB are different. But the power connectors that plug into other boards are compatible between the Classic and Classic II – after all, you can upgrade a Classic to a Classic II by swapping the logic board.

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All of that is true, but that wasn’t even what I was referring to. I worked on two different classics, both with Rev A style boards, that had a slightly Different capacitor layouts. It was odd, but it happened.

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@LaPorta
Thanks for the list via email. I'll share a cart after I order.

 

Removed all caps from the analog board and validated all the values. Used solder sucker, worked well. No real issues besides getting heat on bigger pads.

 

large.IMG_20200718_220412.jpg.1690ed3dd3f92c87257dc6a9024787f6.jpg

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Good workmanship!  Love the photos.  I buy all my caps from Mouser as well.  They have reasonable shipping charges.  And I like the fact that I can buy 1 cap, or 100.  They have been a good company for me. 

 

mraroid

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Here's the mouser cart with locations, though 2 of them are out of stock... Since this is my first time doing a direct order could someone help validate these replacements? (or offer their suggestions)

 

Current Cart:

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=48e4badd71

 

1000uF 35V Out Of Stock

https://www.mouser.com/ProductDetail/667-EEU-FS1V102LB

Replacement?

https://www.mouser.com/ProductDetail/Wurth-Elektronik/860040578014?qs=0KOYDY2FL2%2Fruv7wsM5kuA%3D%3D

 

470uF 25V Out Of Stock

https://www.mouser.com/ProductDetail/710-860020474014

Replacement?

https://www.mouser.com/ProductDetail/Wurth-Elektronik/860010474013?qs=sGAEpiMZZMukHu%2BjC5l7YRTxnIahtzp%2Beh0UIgn8eFo%3D

 

Thanks!

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Any cap of the same specs of capacitance, and the same voltage or higher is ok, provided that the cap isn’t craZily tiny...you’d run into heat dissipation issues. You can look them up right there on mouser

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Right - I did look them up and provided what I think is a valid option - but the comment "crazily tiny" are what worry me. I'm not an EE - I don't know what I don't know :) I'm learning and want to know more!

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I’m not either, just average joe fixing his machines. What id do is look up the ones you were going to order and see the diameter and length on the website. As long as they are roughly the same they’ll be fine.

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8 hours ago, erichelgeson said:

Right - I did look them up and provided what I think is a valid option - but the comment "crazily tiny" are what worry me. I'm not an EE - I don't know what I don't know :) I'm learning and want to know more!

Grab a set of calipers ($20 at Harbor Freight - https://www.harborfreight.com/6-in-digital-caliper-63711.html ) and measure the diameter of the original capacitor, then try and find something similar to that.

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Yes that’s how I got my original measurements. But for now just see the measurements of the parts that are on the list and look for similar.

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I really do appreciate the guidance. I personally feel uncomfortable with my current knowledge to pick exactly what I need. I ended up going with a Console5 kit as it's the easy way out (found they list all the exact info on their wiki pages). And honestly the price was within $2. I'm glad I went through everything as detailed as I did as now I have a map out of every part, value, etc for when the parts come. Now we play the waiting for capacitors game.

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13 hours ago, erichelgeson said:

I really do appreciate the guidance. I personally feel uncomfortable with my current knowledge to pick exactly what I need. I ended up going with a Console5 kit as it's the easy way out (found they list all the exact info on their wiki pages). And honestly the price was within $2. I'm glad I went through everything as detailed as I did as now I have a map out of every part, value, etc for when the parts come. Now we play the waiting for capacitors game.

I've been using the Console5 kits lately and have been happy with them. Its mostly a convenience thing, since like you I get overwhelmed by trying to find the right parts at DigiKey or Mouser.

 

Plus, you get an Atomic Fireball in the box with your order :-)

 

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Caps came yesterday - did the logic board today and tested it in my working Classic II - wish more Macs came with bootable rom.

 

The recap went well, always one joint I dont like and have to retouch.

 

First boot it gave me a checkerd screen, then rebooted a few times in a row, then was fine. Subsequent reboots had no issue.

 

Analog board will be tonight or tomorrow.

 

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8 hours ago, erichelgeson said:

wish more Macs came with bootable rom

Yes!  The boot-from-ROM is one of the reasons the Classic is one of my favourite machines

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