Checkerboard Macintosh Classic

[smoo]

Hello everyone,

I recently got my hands on a Macintosh Classic and it has the infamous checkerboard.
When I opened up, the previous owner removed the logic board battery and the hard drive (but left the hard drive connector), and there wasn't a visible corrosion.
This being my first time working with vintage computer stuff, I did fair amount of research.
So far, I

1. Cleaned up the logic board by dipping in IPA for few hours, brushing the dirt off with toothbrush and letting it dry for a day.
2. removed the rom chip from the logic board to clean and put it back in (in the right port)
3. Since mine came with the RAM extension daughter board, I've tried booting it with and without.

I am currently planning to recap the capacitors in the very near future.

That being said, I have some questions:

1. Is there any other things that I can do to test the board before I recap the them?
2. What are other causes of checkerboard other than bad capacitors and rom?
3. Since mine doesn't have a hard drive, does it boot to the floppy disk with the question mark?
4. I would like to give it a little speed boost by installing blue scsi, is there any resources or guide that I can follow to set up the mac os? (most of the videos that I found online was more of a review than guide)

Thank you in advance to anyone answer my questions.

 

[Nixontheknight]

check the voltages from the floppy port. I don't have the image that shows which pins to probe, but I'm sure someone will chip in the does

 

[Yoda]

1. Is there any other things that I can do to test the board before I recap the them?
2. What are other causes of checkerboard other than bad capacitors and rom?
3. Since mine doesn't have a hard drive, does it boot to the floppy disk with the question mark?
4. I would like to give it a little speed boost by installing blue scsi, is there any resources or guide that I can follow to set up the mac os? (most of the videos that I found online was more of a review than guide)

My Classic required an ultrasonic clean - there was cap goo and signs of corrosion in several areas which an IPA wash didn't seem to sufficiently remove. After the recap, it then booted perfectly.

The Classic should give you a floppy/question mark icon if there's no hard drive, but with this machine there's also the option to boot it to a minimal System 6.0.7 (I think) in ROM. On restart, hold down Command-Option-X-O, and you should get a functional system.

A blueSCSI will give you a marginally faster system - more that it will run a little more smoothly if mine is anything to go by - and it should feel fairly responsive. As for setting the blueSCSI up, I must admit that all I did was use Disk Jockey to create a blank 2Gb image, then ran a Mac OS 7.1 install from floppy disk. It was fairly slow, and here are ready-made images to copy to a microSD card to get it up and running faster, but I rather wanted the original set up experience!

You could also use an emulator such as BasiliskII (Mac/PC/Linux) to mount an image and then install everything.

 

[smoo]

check the voltages from the floppy port. I don't have the image that shows which pins to probe, but I'm sure someone will chip in the does

This worked! The voltage from the port was significantly lower than the numbers I found online, and now my macintosh is booting into a question mark floppy disk. Thanks!

Is there any reason why the voltage got so lower than what its supposed to or is it just analog board getting old?

 

[Nixontheknight]

This worked! The voltage from the port was significantly lower than the numbers I found online, and now my macintosh is booting into a question mark floppy disk. Thanks!

Is there any reason why the voltage got so lower than what its supposed to or is it just analog board getting old?

capacitors. If you have not had the analog and logic boards recapped, get them recapped as soon as you can

 

[smoo]

My Classic required an ultrasonic clean - there was cap goo and signs of corrosion in several areas which an IPA wash didn't seem to sufficiently remove. After the recap, it then booted perfectly.

The Classic should give you a floppy/question mark icon if there's no hard drive, but with this machine there's also the option to boot it to a minimal System 6.0.7 (I think) in ROM. On restart, hold down Command-Option-X-O, and you should get a functional system.

A blueSCSI will give you a marginally faster system - more that it will run a little more smoothly if mine is anything to go by - and it should feel fairly responsive. As for setting the blueSCSI up, I must admit that all I did was use Disk Jockey to create a blank 2Gb image, then ran a Mac OS 7.1 install from floppy disk. It was fairly slow, and here are ready-made images to copy to a microSD card to get it up and running faster, but I rather wanted the original set up experience!

You could also use an emulator such as BasiliskII (Mac/PC/Linux) to mount an image and then install everything.

I had to change the voltage from the analog board to get it out of the checkerboard.
Could you recommend where I could get the capacitor to replace the old ones? I found https://console5.com/store/macintosh-classic-smd-tantalum-main-pcb-cap-kit.html and was wondering if there are other/better options..

I will look more into blue scsi. Based on what you said, I should be able to get a floppy with mac download file and run it on blue scsi, right? and what should be the format for the sd card that I use on blue scsi?

Thanks!

 

[smoo]

capacitors. If you have not had the analog and logic boards recapped, get them recapped as soon as you can

I found this: https://console5.com/store/macintosh-classic-analog-pcb-cap-kit.html for the anaolg board capacitors. Do you recommend other places for the caps?

 

[Nixontheknight]

I had to change the voltage from the analog board to get it out of the checkerboard.
Could you recommend where I could get the capacitor to replace the old ones? I found https://console5.com/store/macintosh-classic-smd-tantalum-main-pcb-cap-kit.html and was wondering if there are other/better options..

I will look more into blue scsi. Based on what you said, I should be able to get a floppy with mac download file and run it on blue scsi, right? and what should be the format for the sd card that I use on blue scsi?

Thanks!

I've never used BlueSCSI, only SCSI2SD, but I believe the card should be formatted FAT32. ExFAT might work, but I'd check with others that have used the BlueSCSI to see if that works. And usually, I just order caps I need off digikey or mouser, but cap kits are the best way to go, especially from console5, they're very reputable and I'm sure lots of people can and will vouch for me

 

[smoo]

I've never used BlueSCSI, only SCSI2SD, but I believe the card should be formatted FAT32. ExFAT might work, but I'd check with others that have used the BlueSCSI to see if that works. And usually, I just order caps I need off digikey or mouser, but cap kits are the best way to go, especially from console5, they're very reputable and I'm sure lots of people can and will vouch for me

Sounds great! Thanks for help!

 

[Nixontheknight]

any time, enjoy that Macintosh Classic! I used to own one, but I hated how slow it was on system 7.5 and was too stubborn to put it back to 7.1 or earlier, so I'm keeping my eyes peeled for a Classic II

 

[smoo]

any time, enjoy that Macintosh Classic! I used to own one, but I hated how slow it was on system 7.5 and was too stubborn to put it back to 7.1 or earlier, so I'm keeping my eyes peeled for a Classic II

Yeah I hear that classic was on the cheaper end so was slower and has long term issues like bad capacitors.

Do you usually just go on ebay? I was able to get a good deal on mine, but the shipping fee was horrible.

 

[Nixontheknight]

Yeah I hear that classic was on the cheaper end so was slower and has long term issues like bad capacitors.

Do you usually just go on ebay? I was able to get a good deal on mine, but the shipping fee was horrible.

I usually check sites like ebay or mercari, but I have a few machines i got locally