68kMLA Classic Interface

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Macintosh Classic (I/II) analogboard recreation (820-0525-A)
Posted by: daanvdl on 2024-04-26 02:14:51
I've been working on recreating the Macintosh Classic late revision analog board for quite a while.
This board can be reconfigured to both 110V as 240V, although i have not test 110V setup yet. This revision board should be able to replace any Classic I or II revision (early/late) analogboard.

The BOM, power- and monitorsection schematics are added to the GIT repository.
After deploying multiple boards, finetuning the recreation and continuing implementing improvements the day has come: I finished my work and published it to my github.

board.png

The files, schematic and BOM can be found overhere:
github.com

GitHub - daanvdl/Classic-Analogboard-Late: Macintosh Classic II Analogboard recreation (820-0525-A)

Macintosh Classic II Analogboard recreation (820-0525-A) - daanvdl/Classic-Analogboard-Late
github.com github.com

Have fun with it!

Cheers,
Daan
Posted by: 68kPlus on 2024-04-26 03:31:21
Ooh nice! Any SMD parts on the Classic type B board?
Posted by: daanvdl on 2024-04-26 03:36:03
Ooh nice! Any SMD parts on the Classic type B board?
No, 100% Through-hole 🙂
Posted by: 68kPlus on 2024-04-26 03:36:42
No, 100% Through-hole 🙂
Ooh nice. Might have to do that with my Classic type B board if it comes to it.
Are there many differences between the Classic I and Classic II board types?
Posted by: daanvdl on 2024-04-26 03:42:56
Ooh nice. Might have to do that with my Classic type B board if it comes to it.
Are there many differences between the Classic I and Classic II board types?
Apple did use mainly the early revision for the Classic I, and the late revision for Classic II, although i have seen the other way around.
I am not 100% sure if that is a later boardswap or a factory thing. Nevertheless; They are interchangeable.
Posted by: 68kPlus on 2024-04-26 03:44:38
Apple did use mainly the early revision for the Classic I, and the late revision for Classic II, although i have seen the other way around.
I am not 100% sure if that is a later boardswap or a factory thing. Nevertheless; They are interchangeable.
The Classic I type A board can't be used with a Type B yoke and vice versa though.
My Classic I is a Type B.
Anyway, do you have Type A and B PCBs?
Posted by: daanvdl on 2024-04-26 03:48:53
The Classic I type A board can't be used with a Type B yoke and vice versa though.
My Classic I is a Type B.
Anyway, do you have Type A and B PCBs?
Regarding this threat the A/B yokes may be interchangeable pinwise, but i did not test that so i can not conform that. This board is a replica with the B-type yoke.

The Compact Mac CRT Guide

It seems to me that the pattern of holes showed up on analog boards sometime in late 1991 or early 1992 around the time the Classic II came out. Apple may have been using up older stock of case backings, sort of like how they made SEs in 1991 to presumably use up parts. The sound vents are...
68kmla.org 68kmla.org
Posted by: 68kPlus on 2024-04-26 03:51:53
Regarding this threat the A/B yokes are interchangeable, but i did not test that. This board is a replica of the B-type.

The Compact Mac CRT Guide

It seems to me that the pattern of holes showed up on analog boards sometime in late 1991 or early 1992 around the time the Classic II came out. Apple may have been using up older stock of case backings, sort of like how they made SEs in 1991 to presumably use up parts. The sound vents are...
68kmla.org 68kmla.org

Are the early and late Macintosh Classic analog boards different?

Were the late analog boards in the Mac Classic noticeably different to the early models? Are late style yokes compatible with the early boards (with adapting)? I ended up with the wrong type CRT and would love it if somebody could help me out figuring this out.
68kmla.org 68kmla.org

They're really not. I have a Type A CRT and a Type B, and the connectors are incompatible.
Posted by: 68kPlus on 2024-04-26 04:03:12
Regarding this threat the A/B yokes may be interchangeable pinwise, but i did not test that so i can not conform that. This board is a replica with the B-type yoke.

The Compact Mac CRT Guide

It seems to me that the pattern of holes showed up on analog boards sometime in late 1991 or early 1992 around the time the Classic II came out. Apple may have been using up older stock of case backings, sort of like how they made SEs in 1991 to presumably use up parts. The sound vents are...
68kmla.org 68kmla.org
Yeah maybe pinwise, but I think the components on the board are also different, so I wouldn't want to try.
Posted by: chiptripper on 2024-05-01 11:06:44
This is wonderful, thanks for doing this valuable work. I often run into Classic analog boards that are fouled by cap plague in the output circuit, I need some of these!
Posted by: daanvdl on 2024-05-01 11:20:32
That's nice of you, thank you!
Many people don't understand how much work it is to get to an end result of a recreation. Many take these kind of boards for granted, while developing such boards takes months of work. In addition, the costs can never actually be recouped. I see it as a gift to society 🙂
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