Mac Colour Classic "upgrade"

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Mac Colour Classic "upgrade"

Postby mrad01 on Thu Jan 09, 2014 9:43 am

I managed to get a great condition, ex-school Macintosh Color Classic to add to my compact Mac collection. While it is a great little box with an awesome little Sony screen - it is slow. Slower than you could imagine. Really. 16MHz 68030 on a 16 bit bus. Slow.

One little known fact is that a motherboard from a Mac LC575 will fit in without modification. It has a 33MHz 68040 (LC040 really - no maths co-processor)

Image

So I tracked down a Mac LC575 and put the board down next to the Color Classic board. Same size and connector.

Left: LC575
Right: Color Classic

Image

Not much work to do there - so I put the motherboard in and fired it up. Unfortunately, it started up with a bus error. The LC575 tries to set a resolution of 640x480 and the Color Classic can't do that - it is set to 512x384 in hardware....so we should be able to change it then eh?

Short answer - yes. There is an analog board modification you can do to the Color Classic which enables 640x480. Details here: http://colourclassicfaq.com/highres/index.html
In the end you just cut a trace, solder in a wire, remove a resister and bridge a jumper. Easy.

Follow the instructions on the site - be very careful with the voltages around the tube and analog board. Couple of pics from the site:

Image

Image

With the 640x480 mod done - I fired it up again - booted perfectly and it is really fast! Here is a pic of the machine after the changes - note the trash can is in the position of the old screen resolution edge.

Image

NOTE: I did have to add in a capacitor to the analog board to bring the horizontal position across enough on the screen - but after adjusting it up - it is stunning. Details on the site above. Such a sharp little screen and a great little compact Mac to have around.
I also took the backing plate from the LC575 and trimmed it down to fit into the back of the Color Classic. The standard Color Classic backing plate doesn't quite line up.
Last edited by mrad01 on Thu Jan 09, 2014 9:57 am, edited 1 time in total.
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Re: Mac Colour Classic "upgrade"

Postby tezza on Thu Jan 09, 2014 9:48 am

Nice.

The form factor of these colour classics has always intrigued me. With those 4 stumpy legs it is a strange shape.
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Re: Mac Colour Classic "upgrade"

Postby Carcenomy on Tue May 06, 2014 12:54 am

Oh they're a lovely little thing. I'd always considered the option of building a CC/PM5500 hybrid, having all that PowerPC oomph in the beautiful little format of the CC. Problem now of course is that CCs are getting too uncommon for those kind of hijinks! :)
Just the local Commodore hobo and middle-aged PC hoarder.
eisa on Trademe. A lasting reminder of a Compaq fetish when I was younger.
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Re: Mac Colour Classic "upgrade"

Postby Audronic on Tue May 06, 2014 11:35 am

@mrad01

Thanks for the article and the link I have one of these in the workshop.
It has encouraged me to look at upgrading it.

Thanks

Ray
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Re: Mac Colour Classic "upgrade"

Postby Carcenomy on Tue May 06, 2014 8:00 pm

Figure out how to ship it and I'll sell you an LC575 as a donor Audronic ;)
Just the local Commodore hobo and middle-aged PC hoarder.
eisa on Trademe. A lasting reminder of a Compaq fetish when I was younger.
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Re: Mac Colour Classic "upgrade"

Postby Audronic on Tue May 06, 2014 9:59 pm

@carcenomy

Thanks for the offer i have some in the workshop,
Still busy with the FreHD and an old Model 1
upgrading the Rom to Auto Boot.They are Very quick.
and a Low-tech TRE-80-IDE Hard Drive setting it up
with 2 Systems LSDos and LDos on the same partition,
etc------>>>>

Thanks again for the Offer
Ray
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Re: Mac Colour Classic "upgrade"

Postby tezza on Tue May 06, 2014 11:01 pm

Audronic wrote:Still busy with the FreHD and an old Model 1
upgrading the Rom to Auto Boot.They are Very quick.
and a Low-tech TRE-80-IDE Hard Drive setting it up
with 2 Systems LSDos and LDos on the same partition,
etc------>>>>

Exactly what I've been doing the past week or so too...except with a Model 4. :)
Tez (Terry Stewart) (Administrator)
Collection: https://www.classic-computers.org.nz/co ... /index.htm
Projects and Articles: https://www.classic-computers.org.nz/blog/index.htm
Twitter: @classiccomputNZ | YouTube: Terry Stewart
Trade Me: tezza5
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