Cpu

Can the main CPU on the Shruthi, if corrupted or damaged, result in numerous intermittent faults?

Something like this is veeery unlikely to happen

No, it either work or doesn’t…

Can you describe your problem?

The main issues>>

(1) Depressing the button to select the filter, does not select the filter, it selects the ADSR
(2) The unit works fine for a minute, then freezes
(3) Resonance on the filter works, but cut-off does not
(4) Sound is perfect, then on next boot it does not work at-all
(5) The LCD display works, then on next boot it displays mixed up characters

All these faults (amongst others I cannot call to mind) appear randomly…which makes identifying the issue, very, very frustrating!

LCD

You have almost certain multiple issues of bad soldering. Post HighRes Pics of bot Sides of both boards, we are likely to spot something - we are the ones that landed Philea so we are capable of troubleshooting your Shruthi round the corner almost certainly :wink:

> The unit works fine for a minute, then freezes

These kinds of errors are often caused by either heat buildup or lack of power. It may not be the case here, but it’s still an idea worth to explore during troubleshooting.

Pics

Yeah, I’d wager a beer that re-doing the soldering will fix it instantly(Well, minus the time it takes to do so).
Pay extra attention to the ground pads(Circles with four little tabs protruding in on them), those take more time to solder, since they suck away heat.

The Ground pad on the output expansion header of the control board looks suspicious to me.

as V’cent says……

Thank you all…

I think I found the problem, a track had lifted on the 6 pin side…I thought it best to remove the 8 pin header to inspect that, 3 tracks had lifted there also :confused:

I fixed that by scrapping back the track and tinning them right up to the contact, if that fails I guess I will have to use some wires to connect it all up…

After resoldering new pins, and fitting a salvaged 8 pin cable, the board works fine with no intermittent freezing or weirdness!

I am going out to try and find a 6 pin cable now, hopefully when thats fitted everything should work fine??

Q. should this board produce sound without the 6 pin cable??

Thanks again :slight_smile: