forum.defence-force.org

Many cartridges exist for several retro machines which allow to diagnose faulty components such as DRAM and test features such as keyboard input, audio and video output.

For the C64, there is the "C64 Dead Test" cartridge (https://www.thefuturewas8bit.com/shop/c ... dtest.html).
For the C16 family, the C264 (https://www.thefuturewas8bit.com/shop/c ... g-264.html, with detailed implementation details: https://web.archive.org/web/20180925161 ... iag264.htm).
For the VIC-20, http://blog.tynemouthsoftware.co.uk/201 ... -kits.html.
And I know that there are many others for Atari 8 bit machines, and likely many other systems.

The feature set of these cartridges is usually the following:

• capable of replacing the original boot sequence with their own (to work around potential RAM issues which the original boot sequence could use)
• RAM tests
• CPU model test (tests all known opcodes and verifies CPU model when possible)
• video and audio tests
• keyboard test (reads/verifies) user inputs
• joystick tests
• possibly tape tests by having the diagnostic cartridge also plug into the tape port and generate appropriate signals.

I did a cursory search regarding Oric diagnostic cartridge but have not found anything yet.

So I am now wondering:

• Does anyone know of existing old or modern diagnostic cartridges for the Oric line of computers?
• Could some of the modern boards in development be somewhat repurposed with this feature in mind?

Thanks!

Here is the one: Diagnostic ROM and PCB by @mikeb.
Soon there will be another one ... I think .

Thanks Iss!

It looks like people only refer to @mikeb's diagnostic program as "ROM" rather than "cartridge" since the cartridge form is optional. This explains why I was not able to find anything about it: I searched for "Oric diagnostic cartridge" and not "Oric diagnostic ROM".

@mikeb provides instructions on how to build such a cartridge/board but are there people who sell pre-made boards with the corresponding loopback connectors?

Also, from your last sentence I gather that you are currently working on a diagnostic expansion/cartridge yourself. Can you tell us more?

Is this a variation of Jede's expansion board or a completely new design?

IIRC Fabrice "Euphoric" also made a diagnostic ROM long ago, I even seem to recall it was speaking in case of faulty display, saying if components were OK or not. (don't expect beautiful sound though )
Can't find it back right now.

Symoon wrote: ↑Sun Mar 31, 2019 8:11 am IIRC Fabrice "Euphoric" also made a diagnostic ROM long ago, I even seem to recall it was speaking in case of faulty display, saying if components were OK or not. (don't expect beautiful sound though )
Can't find it back right now.

Thanks!
I actually ironically found it yesterday a few hours after posting while I was busy working on the Defence Force wiki and found it mentioned there.

Here is the page for those interested: http://wiki.defence-force.org/doku.php? ... ams_are_ok.

There was someone on Facebook that made a few of these, but all the spare ones were sold, I think.

If anyone around here is still making some diagnostic cartridges, I would be interested by one

I've an old machine that had been exhibiting issues and finally died, and with my gf we decided to get back on practicing our electronic skills, so that would be the perfect opportunity!

Well the diagnostic ROM can be used without the additional board. You just swap the Oric ROM for it and boot up.


I think Richie (Vyper) on the AtariWorld forum made one for himself and he'd probably be willing to build you one. I think they need a few boards to make it worthwhile getting the boards made.

I got mine from someone on Facebook it may be worth asking on there if anyone is interested in building a few more, if Richie doesn't want to make one.

Thanks, I've asked on the forum

So, I got Vyper's diagnostic cartridge, and tried it on some of the Nova 64, but I'm not quite sure about what the status led mean: What does it mean when on startup the 6 led briefly appear and then only the led D2 is on, and the machine frozen with a loud electronic weeerrrrring sound?

Ooh, will this work on Telestrat? I seriously need help getting mine booting again.

No, it's designed for Oric-1/ Atmos.

Mike Brown is the guy to ask about this.
The information is on his site.
http://oric.signal11.org.uk/html/diagrom.htm

I think LED2 is indicating a RAM failure.

Steve M wrote: ↑Sat Mar 28, 2020 6:56 pm I think LED2 is indicating a RAM failure.

Ha ok, so LEDs are basically just writing a number in binary, which is the status code?
Guess I'll have to unsolder the ram chips and try to replace them, see if that helps.

Thanks.

Dbug wrote: ↑Sat Mar 28, 2020 7:29 pm

Steve M wrote: ↑Sat Mar 28, 2020 6:56 pm I think LED2 is indicating a RAM failure.

Ha ok, so LEDs are basically just writing a number in binary, which is the status code?
Guess I'll have to unsolder the ram chips and try to replace them, see if that helps.

Thanks.

Thanks SteveM -- it would be helpful if whoever is making and distributing these things pointed buyers to the website with how to use them, and what it is doing, otherwise they are not that useful!

I have no idea how this Diagnostic board/ROM works outside of Oric/Atmos (i.e. other models). If the hardware is similar enough, things may work, but it wasn't intended for that It was only tested against 48K models, but should work for 16K.

The LEDs are on the address bus (buffered). In the event of an error where no screen communication is possible (how to write to screen when RAM is broken, ULA misfiring, etc.) the code goes into a memory-address aligned 4 byte loop (HERE: JMP HERE, NOP). This puts A0,A1 as rapidly cycling, A2 .... are reflected on the LEDs to show a stable state related to the error code.