Mega STe stability issues.

[Maximilian]

Default fixes done?

[Dbug]

Default fixes done?

Not sure what all the default fixes are, I've only done the PSU recap and replaced the 68000 by the low power model.

[Steve]

Default fixes done?

There aren't any 'default fixes' for a Mega STe apart from what Dbug has already done. Apart from the possibility that swapping data/address bus SIL resistors with 2.2k may help, but I don't know if anyone has tried this on an Mste.

Seems like it's an issue with NOVA anyhow... I personally would think a good way to diagnose would be sending your NOVA and Mach32 to another Mste owner to test, this is probably the most logical step in my opinion...

[Dbug]

Just a thought: The machine had a fuse blown on the motherboard (the one that powers the cartridge/rom port), are there any other fuses on the machine, maybe another one has failed somewhere else, leading to a situation where there is still some power that reaches some parts but by detoured ways not enough to be properly stable when disk operations or heavy work is being done?

[mikro]

The more you'll be postponing the test(s) on stock machine, the longer you'll be running in circles.

The easiest (and most reliable) way to diagnose is:

- bare machine
- test
- add one addon
- test
- add another addon
- test
...

[HigashiJun]

So true.

[frank.lukas]

Do not change the Resistor Arrays to 2,2k that is unnecessary/nonsense. There are often big problems with the cpu plcc socket, i.e. contact problems that can you drive mad.

Nova VME: You need the "PlusII" GAL for the MACH32 in the MSTE. You can not use a nova primarily for a ET4000 use with a MACH32 or an other card. Also you can use the "OGFA" GAL but for that you need to patch the Nova Adapter.

I have a Mega STE with 10MB Ram with a MagnumSTE, c´t IDE Interface, FPU and a Nova VME. The Machine is original and rock stable ...

[exxos]

@frank.lukas While I have not done much work on the MSTE, just because your own personal machine works does not represent EVERY machine in the world.Every machine has its own issues / quirks / faults which take various fixes / mods to resolve. What's the alternative anyway ? Bin the machines ?.Some may work perfectly without modifications, some may not. Do you really think if 500+ people had your exact setup that every machine would work perfectly without issue ? Atari themselves dropped from 10k to 4.7k over the years. So clearly there was a reason to do that! I repeatedly keep trying to explain this to people this and it gets very tiresome after a while!

[Steve]

Do not change the Resistor Arrays to 2,2k that is unnecessary/nonsence.

I just want to reiterate that I recommend he trouble shoot the NOVA first before doing anything else. But I would like to know what proof you have that changing resistor arrays in Atari computers is nonsense. There are many reports of great success on this forum where doing this increased the stability of a system, and myself personally I have fixed stability issues on my machines doing this too.

So the way I see it, here we have seen absolute proof that changing resistor arrays improves system stability. You have zero proof against it. So throwing opinions around like 'nonsense' is unscientific and dangerous.

[Dbug]

I have removed the VME card, machine still worked fine.
I removed the monster card and replaced the low power CPU, machine did not boot and I got "Invalid Video mode" on my screen.

image_2022-04-27_161607404.png

I removed the cpu and put back the original 68000, machine did not boot and I got "Invalid Video mode" on my screen.

image_2022-04-27_161639509.png

I removed the cpu, put it back on the MonSTer and the MonSter back on the ST, worked.

image_2022-04-27_161737343.png

(That being said, when running Kronos, it still ends up crashing with a few bombs after it was done doing a bunch of tests)

I'm starting to wonder if the weird connector of the MonSTer did not somewhat push back the pins inside the connector so the cpus are not able to touch the pins anymore.

Not sure what to do