Buttons not working on Shruthi-1 [SOLVED]

.:EDIT:. I did finally get the shruthi to work by using a new 8-pin connector. Unfortunately not none of the buttons are working. Please help.

.:EDIT2:. She works beautifully! Thanks for the help everyone!

Is the polarity of the barrel jack correct? Remember doing that wrong myself.

Centre pin Positive, Sleeve Negative.

Yep that fixed the problem. It turned on but now I’m getting no sound out. Maybe a problem with the filterboard?

Are you sending midi or using the JAM mode?

Sending MIDI via a sequencer. Test note doesn’t work.

At this point I should add that while soldering I put the 8-pin connector in the wrong way and had to desolder it so it is very possible that I destroyed the traces for all of those connections.

Do you have a multimeter with continuity (beep) function, then check those pins against test points down the line.
See here for test points (assuming you have the SMR-4 board): http://mutable-instruments.net/shruthi1/build/smr4mkII

Maybe stupid question, but did you put in the jumpers for the in/out jacks?

Sorry for chiming in…i have two points here:

  1. is the filter type set correctly in the system settings under “fil” ?
  2. to check the soldering of the 8-pin connector high res photos of both PCB sides would be helpful

Jensu: I have not put jumpers in the in/out jacks, do I have to do that to get sound out?

Nightworxx: I haven’t set the filter type but I figured you’d still be able to get sound out. I’ll post pictures of the PCB and multimeter readings when I get home.

Yes. The pads are there to add a Gain-pot if you use a custom case. You have to solder a jumper in as marked, otherwise there is simply no connection between the jacks and the circuit.

See “Step 13” of the assembly manual.

Ah I see. I’ll do that when I get home and update on what happens.

I am not sure if this is valid for the 4PM and the SVF, as i do not own them.

It is. All official Mutable filter boards have those pads.

I sometimes think it would have been better to have those pads connected by default and anyone that wanted gain pots could cut a trace.

Bridged the audio out pads and switched the filter mode to 4pm, still nothing. These are the pictures of the pcb:

Messed up solder pads


I checked the voltages on the 8 pin connector that I messed up while desoldering:

VCA= -2.5v
F= 0v

It’s also worth noting that the LED comes on and off intermittently, like if I lightly bump the filter board.

Sweep the filter and see if you get anything on the F pad. See if you get any voltage on the VCA when you press a note.

You should also make a audio probe to see where you get sound and at what point it stops. The OSC pad will be audio, so measuring a voltage isn’t really sensible.

I’m getting audio out at the Osc pin from the 8 pin connector but somehow it’s not getting to the audio out jack. VCA reads -2.5v. I can pick up the audio signal from various resistors but the filter is finicky. It doesn’t always work when I sweep the cutoff frequency.

OK! So now the shruthi is on and working but none of the buttons work. Only the encoders. I’m assuming this is a problem with the resistor network or the 165N chip. Any ideas?

Might be the resistor network being reversed, or the wrong part (if you self sourced), some have a common pin, others are just individual resistors.

I bought a kit from tube ohm so the parts are good. RN1 is placed correctly. I checked that the resistor network is working and I can watch the voltages drop from 5 to 0v for all buttons and their respective pins on the resistor.

Is the 165 chip in the right place? swapping those two chips is a common mistake.