LCD in a Color Classic.

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LCD in a Color Classic.

Hi Everyone, this is my frst post here, and I stumbled across Applefritter as a Classic Mac site by chance although i used to lurk here occasionally.

Longo story short, during the COVID Lockdown I got bitten by the Vintage Mac Syndrome and trcovered from my basement a number of classic Macs i had in the years: an Apple Macintosh 650 in a Quadra 700 case, LC 475, Color Classic, Mac IIfx, Lc6200 with 6500LB, Mac Cube, Mac mini G4 1.42, iMac G4-700,15" LCD, and last but not least, Mac Pro 5.1 12 core- this is still my workhorse.

Among all these things I got a second Color Classic with a burned and unusable  analog board - the flyback trafo had died. So I got to thing how to replace the CRT and analog board with a moder ATX and LCD display, and while the LCD part was completely solved, the ATX board will not want to work for some reason with the LC575 board that is in my CC.

The rationale behing my endeavour is not "hacking" per say but preserving the machine as CRTs and above all the cheap and poorly made analog boards will all die way before the LB and he rest of the machine.

See it as using a ATX mod in any one of the classic machines, or using today a LCD with a Quadra 700.

However, I got in many problems. I used the Takky mod as a guide to replace the PSU of the analog board, desinging from scratch a replacement PCB that can be wholly inserted where the old AB would be, housing the soft power circuit, SFX/ATX PSU, stereo amplifier, -5V regulator circuit and support for microphone and video out to the LCD-

I will post lots of images and once operational, I will post everything needed to replicate it, Gerbers, sources the works free to everyone.

I am missing some information on how the CC and LC5xx board work, and i am asking help to everyone here so I can complete this project.




Last seen: 2 months 25 min ago
Joined: Aug 27 2023 - 11:05
Posts: 4
Argh it seems I am not able

Argh it seems I am not able to edit the mistakes I made typing on my phone. Meh.

In any case, this is where I am today, the LCD mounted and working in the CC chassis (which has NOT been modified in any way), and the efforts in designing a host PCB that includes PSU, the edge connector that was originally on the old AB and other parts as the AC receptacle and power switch.

The LCD is still available here:

ebay link

Tom Owad's picture
Last seen: 3 hours 46 min ago
Joined: Dec 16 2003 - 15:14
Posts: 3379
Fantastic work, Franco.

Fantastic work, Franco. Looking forward to seeing more. I haven't had my Color Classic out in quite a while, but even years ago the analog board was whining, so it may be a candidate for an upgrade like this.

Dr. Webster's picture
Last seen: 7 hours 50 min ago
Joined: Dec 19 2003 - 17:34
Posts: 1753
That you designed a

That you designed a replacement for the analog board that still uses the internal wiring harness is most impressive -- I've seen LCD mods for CCs before and they always look very hacked together, but yours is very clean and tidy.

Last seen: 2 months 3 weeks ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
Other than the board being

Other than the board being purple instead of green like most Apple made boards that looks incredibly factory.  Really nice work.  I don't have a Color Classic but if I did, that looks like a really good mod to get rid of the CRT.



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Joined: May 12 2022 - 16:58
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How did things work out?

I was just about to do something like this myself and saw this post. How did things work out?  Do you have the board design posted somewhere?  Any pictures of the final working system?

Last seen: 2 months 25 min ago
Joined: Aug 27 2023 - 11:05
Posts: 4
So, I had to place this in a

So, I had to place this in a backburner due to a problem in the PSU : i did not realize modern supplies have too little juice on the -12v rail, that has to be lowered via a 7905 or similar to -5v, for both the serials and audio - problem that actually prevents the LB from booting. The need at least .8 A on the -12v; I found an old small form factor psu from Seasonic that satisfies this however I need to recap it! Also, I have found a couple errors in the PCB, that I am fixing - that means I need to order JLCPCB do a new batch and they are expensive.

btw, anyone is welcome to help me debug the project, I will publish everything so anyone can replicate it once it works!

ex-parrot's picture
Last seen: 1 month 3 weeks ago
Joined: Dec 20 2003 - 01:35
Posts: 6846
Beautiful work! It's hard to

Beautiful work!


It's hard to tell in the photos, is there an insulating spacer between the board routing the mains voltage tracks and the ATX PSU? The solder mask along is not going to be sufficient to safely insulate those traces.


Did you consider a small DC to DC module to generate the negative rails and allow using a smaller form factor PSU?

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