Uhoh

played through the patches, some keys - strait for about an hour, then interrupt by random freezes and quick restores to default… splash screen… filter… .
With the default/reboot the sound is continuous with all but a glitch.
With the freeze there’s no control of the menu, no sound.
I played out a sequence on the drum machine as so to tweek it,
the more frequent it became. Especially when I’d tweaked it.

The first thing it inspires me is a wrong soldering joint or short on the path of the RST trace - when this line is grounded for a short time it causes a reset (hence the name), when it is grounded forever it freezes the CPU. Check the 10k resistor pulling this line up ; or, if you have soldered it, the ISP connector.

If you have problems with a freezing/resetting Shruthi-1 you might check along the yellow/orange line if there is any connection to GND.

Note that the yellow line is on the Front side (the one with the Pots) of the pcb, the orange one on the back side .
You should check between the two green marked spots with your Voltmeter if there is a nice +5v Potential between. If not, check along the line for shorts/bad soldering. Dont forget the opposite side of 10k R that pulls the line to +5V.

Well… I don’t know. I’m getting +4.93 at the 9pin10k intersection to ground. I’m getting .8 at the 5pin on the ISP (but I never soldered that). Not sure where else to go. I can’t find any bad solder points or shorts anywhere.

The system just seems to be freezing now. Not that many resets.

Hmm… I checked again. I’m getting .8 at the 9pin10k intersection and +4.93 coming out. Which makes more sense.

Between which points do you get the 0.8?

I wish I could have a look - It would be unfair to blame your soldering skills since you have already built a Shruti before.

At the green arrow points above as well as pin 9 on the 644 directly and at pin/hole 5 on the ISP.

Not sure I get it… On which point is the “COM” probe of the meter, and on which point is the “V” probe of the meter?

Com is at ground always.

This is supposed to be pulled-up, you should find a value near VCC. I read 4.86.