[SOLVED] My Shruthi just went all glitchy, suggested recovery strategy?

My Shruthi 4-PM, which has been working like a charm for the last 3 years today went all glitchy. Not sure what happened, I have not done anything that could have caused this misbehaviour.
The syntoms of the illness look like this: when you turn it on, at first everything looks ok, but when you play a sound it sounds all distorted and glitchy, shortly after the display will start to show all sorts of weird characters or randomly cycle through different menu pages.
I have a AVRISP programmer here, should I try to re-flash the chip? But maybe there’s something else wrong here… any ideas?

Try reseating the IC’s. Try a different power supply.

As above, check for folded under legs on the ICs.

Try a different PSU: had already done, but unfortunately that’s not the problem.

I’ll check the ICs, I don’t think there’s folded legs, this Shruthi has been working for 3 years.

I did trace back my last steps and the only thing I did today with this Shruthi is test a fuzz pedal with it. I then checked the Fuzz pedal with a DMM and a scope and found that when you plug a cable into into its input, you get a pretty big voltage spike. Could that have caused the firmware on the Atmega to go corrupt?

Two things I would check first:

  1. Is the right hardware selected? Classic/XT-Classic/XT selected with encoder pressed while powering up.
  2. Is the right filter (4PM) still selected and saved?
    Maybe one of these settings have accidentally changed.

Measure the positive and negative voltages to be sure you have and keep stable plus and minus 5 volt. Resolder the 7805 and 7905. Are the 165 and 595 socketed? If they are, reseat them (partially remove them and push them back in) and if you have spares you could try exchanging them. Both are involved in the menus.

> 1. Is the right hardware selected? Classic/XT-Classic/XT selected with encoder pressed while powering up.

Yes that was it! somehow that setting got changed. never would have thought of this. Tanks a lot!

OH MY GOD! Thank you. I was going crazy, I was trying to figure out what was going on! If you turned the fourth pit, it would glitch and flip out. I even tried reflashing! I’m glad to say it works now.