Octatrack MK1 "checksum error" & SRAM [F]

[julius1]

Bought second hand Octatrack and it complains ”wrong checksum” when loading a project. Function test says SRAM [F].

Things i have already done:

• bought new Sandisk Extreme memorycard
• formatted memorycard inside Octatrack
• cleaned and checkd memory card pins
• updated firmware 1.40B
• replaced internal battery CR 2450
• saved project “as a new project”
• duplicated project folder in computer using “usb disc mode”
• duplicated set folder in computer using “usb disc mode”

Would you have any suggestions what i could do next?
I have already created Elektron Service Ticket over a week ago but no respond.

[mrcrappypantson]

I’m pretty sure a checksum issue is a midi issue. Remove midi cables and see if that helps?

[julius1]

i have not plugged any midi cables yet so can’t be the case.

[lowph]

I don’t think it’s MIDI. Pretty sure it’s the checksum of the project on the card, as it seems you suspected.

Have you seen this post?

Checksum Error

In case anyone else gets a checksum error while loading a program on the Octatrack… If you save a new copy of the program and open it, the file’s addresses seem to get fixed and it loads okay. Saw an old forum post but nobody had any answers other than sending a copy of your files to elektron for them to send a fixed version back. Not necessary. Just save a new copy of the program. Hope this helps someone.

Good luck. Hope you get it sorted

[julius1]

Thanks for your suggestion. I have already tested to save a new copy of the program but with no success.

[sezare56]

@julius1

already tested to save a new copy

Is it an important project for you ? Very probably a corrupted file, but which one?
Is it possible to open the project ? (press NO to avoid aborting).

Usually when its a corrupted bank, you can open the project and Save As New. Check if there is a bank in red or orange, can’t remember but an unusual color. Delete that bank. It will be replaced by a new blank one. No more message.

If it is another file and if you can’t open the project I’d make a new project and replace banks and project.work file, then load samples in slots if necessary.

[julius1]

I have no important projects. Anyway i checked and didn’t notice corrupted banks. If i create totally new set and project, i would assume there can’t be any corrupted banks?

[sezare56]

@julius1

If i create totally new set and project

I’d format the card before.

@julius1

there can’t be any corrupted banks?

Still a possibility, but it is rare on a good card freshly formated imho. I had a few problems like that, my card was old, full, had to delete projects. No more problems just after formating.

Safer to create several versions of important projects (Save As New), and backup of course…

[Shredrr]

checksums are in literally all files of an OT project.
bank files (work & strd).
arrangement files
marker file
ot files

If you encounter the checksum error then you have (surprise) a checksum error.
Three typical scenarios causing this.

a) your OT crashed or stalled or was turned off while writing the project files therefore the checksum becomes invalid. For that to understand you have to know that checksums tend to be at the very end of a file to check the sum. literally.

b) you edited either an *.ot file (slices, octachainer or similar), arrX. file or bankX file in another environment than the machine, therefore without the checksum algo likely resulting in a wrong checksum.

c) corrupt medium

What to do?
as each file has a checksum in the octatrack (apart from wavefiles)
you could in theory find out which one is corrupt or let it say different: contains likely invalid or incomplete data.

So …

1. first you check manually if all expected files are existing,
2. then if their file size (in bytes) is correct, hint: all file sets are usually same size according to their name/type in all projects
3. rare but possible a corrupt medium that triggers the error because writing works fine but reading results in data that does not sum up to the checksum, hinting to an area on the physical medium that is broken (corrupted memory).

hard fix:

4. if you can single out one, exchange that file with a blank or one of the other of the same project by copying and renaming.

super soft fix:

5. just agree to load the project anyway, just the checksum is wrong, as the error says.
   Expect weirdo settings somewhere but as the file formats are fixed size the data fields are fixed size as well, therefore likely only one or two parameters might become invalid but not outside their range. Four byte stored data is still in 4 byte, not other bytes and a number stored in such is still a number in exactly that range. So not very much to worry.

From here you can save again (make a backup before you “repair”) and the checksums should be nice again.

tip: a not so beautiful fix for a corrupted physical medium (if there is no better option, like being on tour) is either reformatting and hoping its just the formatting or you force the file system to jump over that memory position by not using it anymore, which can be done by letting the corrupted file where it is and rename it to something completely unrelated so that a project will never load that file again. Which in turn forces the filesystem to skip the memory that this file occupies and with it jumps over the corrupt places. Beware, memory (flash drives) that is corrupt usually comes with more corrupt yet undetected addresses.