Issues loading disk images

[Steve Hayter]

Hi All,

Ashamed to say I bought my kit years ago and only just got around to putting it together. Finished it this aft and it's awesome. Few things aren't working and I figured I'd ask here.

I can load 16K BASIC no problems, but Altair BASIC seems to try to load a BASIC file on launch.  As soon as I press 1 (the first character in 16384) it starts throwing BASIC statements across the screen .. in sequence...  Then the Arduino seems to hang because the only recovery option is power-cycle.

The other problem is with loading bootable disks...  I can mount disks no problem, but as soon as I boot one, the terminal fills with:

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

etc.

I haven't formatted and reloaded the SD card yet, nor have I looked for firmware updates.

Thoughts/suggestions before I spend a bunch of time going down the rabbit hole?

S

[Chris Davis]

Before anything, update your Arduino to the latest firmware: https://adwaterandstir.com/install/

The repeating Cs indicate a checksum error.  Verify the six pin header is installed under the Arduino, that is commonly missed.

[Steve Hayter]

I was trying to boot up Zork … naturally ;-) … following the directions under the Fun Stuff page.

I installed the header … probably one of the first things…. What I don’t recall was a mating header on the arduino?

Will verify as suggested and report back.

Steve

Sent from my iPhone

On Sep 22, 2026, at 12:25 PM, John Galt <furba...@gmail.com> wrote:

it could have also been a disk image without the bootloader. not all the disks are self booting.

have a known good booting disk as the first image then mount the CCCCCCCCCCCCCCCCCCCCCC disk as the second image and then boot and change drives at the command prompt to see what is on the second disk.

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[Steve Hayter]

Quick update: 

1. I took the cover off and checked; the header was installed. Reseated the Arduino anyway. 

2. Updated to the latest firmware successfully. No change, same behavior. 

3. I pulled the SD card out and went through the load procedure...exact same result. 

4. Reinserted the SD card while the kit was powered up, and something caused a short (all LEDs shut off). Wiggled the SD card, they came back. Wiggled some more and they'd blink as I wiggled...  

Soooo, it looks like a bad SD reader (SD card works fine on the laptop). Yes, the headers are installed on the correct side of the PCB.  ;-)

I think I have one I can swap in. Would someone please send me an Amazon link to an appropriate reader in case I don't have one?

Will keep you posted.

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Steve

[Steve Hayter]

Nope. I have a few of these:  https://www.amazon.com/dp/B099KFKDBS

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Steve

[Chris Davis]

That's not the correct sd module for the Altair-Duino.  These are very common and available everywhere: https://www.amazon.com/WWZMDiB-Module-Adapter-Memory-Shield/dp/B0BV8ZQ81F

[Steve Hayter]

Yep. Had already found and ordered from Amazon. Be here in the morning.

Thanks so much though—will keep you posted.

S

Sent from my iPhone

On Sep 22, 2026, at 3:43 PM, Chris Davis <famousd...@gmail.com> wrote:

That's not the correct sd module for the Altair-Duino.  These are very common and available everywhere: https://www.amazon.com/WWZMDiB-Module-Adapter-Memory-Shield/dp/B0BV8ZQ81F

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/2c4a2bcc-3fc8-4969-b77b-6d37b25a0251n%40googlegroups.com.

[Steve Hayter]

All fixed. Two leads were folded under the socket and weren't connected looked factory, but...

Thanks all who helped.

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Steve