Shruthi not working (solved)

Hi Chaps, built up my Shruthi but having problems. Testing out digital control board with +5v supply and no filter board connected and I am getting leds 1, 3, 5 and 7 lit up permanently and the lcd display is just one solid block (not black just the baklit blue)- no adjusting of the trimmer pot has any affect. I have checked all joints carefully and can see no obvious probs. All chips are socketed so I have taken them out, cleaned the pins and replaced. All orientations appear correct. The buttons and rotary encoder have no discernible effect either. Could My atmega be fried? Any thoughts please?

Your Machine is in Firmware Update Mode, it thinks button S6 is pressed at startup. See the Manual for details (rather at the end). Check your soldering especially at the R network and the 165.

hmm thanks for that, this has solved one of the problems - checked the switches and found I had used pushed to break instead of push to make so the AT was thinking all buttons were being pressed on start up - I have disconnected the switches until I replace them and started the Shruthi up again - this time just led 3 and 7 are lit but the lcd display is still just one solid backlit block could the trim pot be knackered?
if I touch the bare wires from the switches to the appropriate pads I can get the leds to cycle through so would that suggest that the AT mega is functioning correctly and it is just a display problem?

The trim pot is often the culprit with obscure LCD problems…

Try turning it to the left for about a minute. Eventually you will hear/feel a faint click in the Trimpot. Then turn it all the other way round to the right. If this doesnt work out check all the Solder Joints to the Display and around the trimmer, especially the GND Connection.

Thanks for the help, now have a fully functioning display - turned out to be a dry joint on the trim pot. Thanks for the help. Now for the $pole Mission filter board. :slight_smile:

I am the remote Voodo Healer :wink:

OK, got another one for you - now the rotary encoder does not appear to be doing anything - it will act as a switch ok but the encoder does not appear to be having any other afect - any suggestions - it is the alps encoder spec’d in the BOM and it is correctly wired in - this is also the second one I have tried, faulty batch maybe?

The encoder contacts go straight to the ATMega pins 1, 2 and 3. Not much can go wrong there except bad soldering or bad socket contacts. Test for continuity between those three pins and the corresponding contacts on the encoder. You did solder all five contacts on the encoder (in addition to the two fixing points) ?

He started a new thread, and got it working :slight_smile:

Thanks for the help, I had started another thread specifically for this problem and was given exactly the same advice about the atmega pins - resoldered one and it worked perfectly - many thanks for taking the time to respond.

I saw that one… Later, of course… Very reassuring that he made the same analysis that I did :slight_smile: