F#&*ing EEPROM again???

[Batz Goodfortune]

Y-ellow Y'all.
	Thank for the suggestions. I have checked for most of those things.
Everything from the humble short and dry joint through to crystallized
solder joints and conductive flux. I've added extra pull-ups down to 220
ohms. I've run the thing on a lab supply and extended the reset period. I
even soldered a pair of new wires in parallel with the board traces incase
there was some kind of weird standing wave effect.

The best lead so far goes like this.

The processor is too fast for the I2C clock rate that the chips can handle.
It's supposed to be 400K minimum but it could be the older 100K types. I
got away with it for a long time until the ambient temperature and
conditions changed and now it just isn't going to take it. Therefore adding
extra wait states to t he I2C routine should cure the problem.

All except for one thing. I noted when going back through the code that I
already have included extra wait states. Perhaps they're just not enough
now. However it has been almost a year  that this part of the system has
been basically working. I can't figure on why it's suddenly died now.
Seasonally speaking we've been through all of them.

I have since found all my other EEPROMs and tried them all. It could be
that I've just got a bad batch. On the other hand it could be something
else really weird. I had planned to try to take this up to a larger EEPROM
anyway but I really need to be sure of what's going on here.

I will try modifying the code to give an extra long wait state and see what
it has to say about it. And I also found the error handling code that isn't
handling the error quite as it should. Maybe I can do something about that
too?

But I fear this is a real curly one.

For the record. Although it failed  catastrophically suddenly, it didn't
just snap fail. It was showing symptoms over 2 days. I had figured on
another cause and it wasn't urgent on the 1st day. The second day it just
trashed within minutes of it first firing up. It actually hung when I tried
to do a patch change from MIDI. That was the last I saw of it working.

Thanks for all your suggestions. Most appreciated. I'll see what happens
when I change the code.

Be absolutely Icebox.

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