e-licktronic Forum

Hi there. Got my nava working great, except the mux boards. If IC111 & 114 are empty all sounds are present. Seating either of them mutes all sounds for that group. I’m pretty good at smd and didn’t have any issue with the build. Power is good on both boards. It’s gotta be something simple like needing an os update. Thoughts?

Yes, it's needed to update the firmware. Did you do it ?

Updated to 1.027 no change. Switched mux positions no change. Reflowed mux boards, no change. Going to have to inspect the IC traces on main PCB carefully.

Did you quintuple check the 3 pins connectors ? I did the mistake when I built mine, even though I carefully did it.

Quite a lot a people had issues with their boards, but as SMD seems too small for some, we can't be sure to trust if they really had bad boards as they claim.

Otherwise in a last resort you can order these through-hole versions (very expensive) or this "lite" version.

So I just went through a month of trying to get these boards to work. I even laid out my own PCBs and tried those as well but they were also problematic. I finally got things working using the original boards and I think I figured out what was causing my issues.
The low current involved in the charging of the capacitors in the Sample & Hold circuit is EXTREMELY sensitive to leakage currents. Unfortunately something that causes leakage current is flux. The final time I replaced all the ICs on the MUX_SH PCBs I was very careful to use no extra flux and reflow the solder that was already on the pads. Previous attempts to build these boards I had used extra flux on the pads because it make SMD soldering quicker, but I think that was my mistake in this case.

I also used LF444 quad op amps, and metal film 0805 capacitors. These did not solve the issue at all, but probably help with droop now that normal operation has been restored with the flux/leakage current issue resolved.

So for anyone dealing with instruments having very short decays or being completely silent, I suggest removing the ICs and caps from the PCB, cleaning it completely of flux, then building the board again using as little flux as possible.
I also use a Kester solder with water soluble flux so I can wash the entire built PCBs under hot water and scrub with a toothbrush under the running hot water. I then set them on top of a fan blowing upwards for at least a few hours to make sure they're completely dry. In this case, residual moisture can cause the same leakage current issues as the flux, so they need to be COMPLETELY dry before installation and testing.

I hope my month of troubleshooting can help more than just me.

Hi,

Are the MUX_SH boards still needed with Nava PCB v1.02 ? Are they sold with the kit ? On the interactive bom IC111 and IC114 are marked as MUX/SH_Board...

Thanks

Yes, and for sure they come with the kit as the main board couldn't work well without them.

Curious how the individual accent per instrument and the total accent interact board wise.

I have two mux boards that appear to be good. They work perfect in IC114. Accents all fine on BD, SD and Toms with either mux in 114.

IC111 instruments, RS, HC and Closed HH do not change with the accent enabled on a step.

So I don't have any decay or muting problems, just non functioning accent on those instruments. Both mux boards behave the same, despite working perfectly in 114.

Curiously, if I set total accent on I do get accent on the Closed HH but not for RS or HC...

So there is some function of the accent circuit but not when triggered via the HH instrument itself.

I built a stripboard version of the circuit with thru hole components and it is the same.

Wondering if there is anything else I should check and if this behaviour suggests the mux are fine, but I have a problem elsewhere...

Have ordered a set of the lite boards just to try out of curiosity.

Purveyor2 wrote:Hi there. Got my nava working great, except the mux boards. If IC111 & 114 are empty all sounds are present. Seating either of them mutes all sounds for that group. I’m pretty good at smd and didn’t have any issue with the build. Power is good on both boards. It’s gotta be something simple like needing an os update. Thoughts?

Hi
I have exactly the same problem. No sound when the mux boards are in the sockets. Did you find a solution for the problem?
Thanks!

I think my problem is different from most as I still get sound when the mux are installed.

I have 4 mux boards, and 2 nava. I did have one mux that silenced its instruments, resoldered the board, cleaned with IPA and then it worked. So anyone with complete silence, I suspect its the SMD soldering, or the flux residue problem above.

However there is def something strange about 111.

On my v1.02 board none of the 4 work in 111. I still get the instruments but there is no change with accent on or off. I am now wondering if accent is actually stuck on for the instruments
fed by 111 on this board... need to check the schematics and try debugging.

All 4 boards work in 114 on this one.

On my v1.01a board all 4 mux work in either slot
So I know the boards are good. My mux lite order has been shipped from Oshpark, so will report back if that makes any difference, but suspect its something on the main board that's my issue.