Diagnostic Tools for the Vic-20

[MCes]

Why the old PAL & NTSC distinct Diagnostic tool version and not my pal/ntsc cable free hacked version of Diagnostic Tool? and why not my new DeadTest version with additional Keyboard and Video/Audio tests too?

It's just a misunderstanding: "OLD" as "improved mbla000 CLASSIC", "OLD" as "not unreleased"

I corrected my previous post to be clearer

[orion70]

3) an hardware LOGIC STATES ANALYZER on board useful for a VIC20 that does not boot up(not even with DEAD TEST).

Could it be of interest to anyone other than me?

Yep, count me down for one! Dead VIC-20s diagnosed via a LED display - it would be VERY useful.

[beamrider]

I'd be interested depending on cost.

[chysn]

Could it be of interest to anyone other than me?

Given that (1) I seem to be accumulating VIC-20s, (2) I'm gaining greater interest in hardware repair, and (3) I know you make good stuff, then yes, I'd be interested in such a project.

[USA_Joe]

I'm having a strange issue with a VIC-20 CR. The issue is that it fails the diagnostics test for the datasette port. The odd thing is that the datasette can read and write to and from different cassettes without any issues. I tested the diagnostics components on a different VIC-20 CR I have, and everything passes.

What exactly does the diagnostics datasette test check for when it is running? It has been recommended that I use a oscilloscope to compare what's happening on the two VIC-20's when the diagnostics is running. Before I do that, I'd like to know how the diagnostics checks the datasette port.

Thank you!

Joe

[Marsupial]

I am trying to understand what can make the diagnostic report a bad checksum.

I guess the way dead test and diagnostic validate the ROM chip are different, but I followed the advice from Mike on this forum and downloaded a binary of the character ROM, which verifies as good on my VIC-20.

Yeah I made a typo when I renamed it

The diagnostic still declare the ROM as bad, with a checksum that changes every time I run it.

Checksum value changes everytime

I don't understand how that can be. What can make the checksum change everytime if the CPU can get to every bits and successfully verify every time?

Am I missing something?

Is the motherboard at fault? Or the diagnostic?

Motherboard is rev B w/ 2-pin power plug.
I tried 4 different diag from various sources including the ntsc/pal from the first post of this thread.

Help would be greatly welcomed, I am at a loss...

Thanks!