Rack Mount Anushri - No FM PW or Wave Control

Hey all-

Proud new owner of a beautiful eurorack Anushri - black face, green board. I was really stoked with it, until I realized that there seem to be some problems.

I noticed that if I switched the sub-filter off of DCO, that my output dropped out quite a bit, and sounds distorted.

Further experimentation, and I have found that the Linear FM/EXP FM and the PW/PW MOD seem to only generate severe grunge (not the good kind). I wasn’t switching off the DCO position initially, because it seemed to cut the output to subsonic - but I realized after further fiddling that there seems to be something wrong - not just that I was operating it incorrectly…

I also noticed that the wave knob doesn’t seem to have any effect at all, or maybe causes small chirps in faster sweeps but no significant change in tone- I suspect that whatever processing associated with this know (if it isn’t the same as the PW/FM) is not working correctly either. I don’t seem to be getting square wave.

I tried wiggling the ICs on the back, to see if there was a bad connection, or maybe a loose chip, but that didn’t seem to get me there.

Are there any out there (with more knowledge than myself) that might be able to point me towards a solution? the board looks like it is in great condition, and I don’t see any signs of failed components or broken leads, etc. My suspicion is that one or more of the ICs have failed.

I would be grateful for any assistance on this. I’m handy with a soldering iron - (at least as long as it isn’t SMD , in which case I am less handy), but I don’t have access to an o-scope.

It seems like an incredible piece of gear, and I’d really love to get it working properly so I can fully explore its potential!

Thanks in advance for any assistance you can provide!

More probably bad solder joints, a part mounted in backwards or shorts somewhere. Much more often it’s one of those then a failed component.
Check the troubleshooting guide on the end of the assembly guide: https://mutable-instruments.net/archive/anushri/build/

Did you build it yourself? If not get it back to where you got it from.

Unfortunately, I didn’t build it. I wish I had. The board looks like it was soldered beautifully t hough - I did look at it through a 3x magnifier, and I don’t see any connections that looks shady - but I did not disassemble the main/pots boards to look at those. The grunge that comes through the FM section, and lack of any function in the wave knob made me think it wasn’t in the pots though - since it sounds like this board is mostly in the IC processing with a little filtering - since the pots are data inputs.

You are right though, I should run through the troubleshooting - thanks for the link. I had seen that, but it looks like the main processing comes through the big IC. I thought I would see if there was one that specifically handled the FM, PW, and Wave generation.

I would hate to send it back - these black-face rack mount units seem pretty rare compared to the plexi desktop boxes, and I really like having it in my rack. I fear that if I send it back, I may not find another for quite some time - and I will likely end up with something else. It is such a great all-in-one though…

I appreciate you inputs.

All Anushri’s are DIY and all are suited to be mounted in a box or as a eurorack module. Some minor modifications maybe necessary. All files are available for having a euro front panel made somewhere and i think you can probably still order them too at some places.
The Anushri is halve digital and halve analog. It’s a real VCO and a real VCF. There is a second digital oscillator coming from the main MCU (the big IC). All control signals, LFO and Envelops come from the MCU too.

Some off the pots are in the analog signal paths and some of the pots control the digital signals via the MCU.
I think essentially the upper half is analog and the bottom 10 pots are digital controlled an can also switch functions.

What you describe i’m not even sure you have something broken but maybe just dialed in some weird settings.
It’s is possible you have for example dialed in a very fast S&H LFO. The Anushri can be somewhat confusing at the digital end.

Shiftr- Thanks for the tips. I don’t think it is a LFO issue. I did a reset, and picked a steady tone. Take a look at this video and tell me if you think this sounds like it’s user error (it may be) but this sound like garbage to me.

Is the MCU flashed? I assume I could try replacing that (it is a $2 part) and refresh it. The pots seem to be working (with the exception of the death zone at 8-9 o’clock) - but I can’t tell if that is the pot or the grunge demon that is living in this thing…

Can anyone tell me which of the ICs are responsible for the FM/PW and Wave sections? The assembly instructions aren’t super helpful in that regard - I do see test points on the MCU for these.

I’ll take some readings and share my results.

Are any of the buttons with the Leds working? If so the MCU is flashed and working.
Where are you from? There used to be a list of trusted builders on the forum. You can contact anyone on there to see if they can have a look. This frontpanel actually looks a lot like one 1 made.

All the button LEDs are working. Everything else seems to be working - though the tone seems a little different than sample videos I have seen.

I bought this from a guy in Italy and had it shipped from Naples (Napoli). Paid a good bit for it, plus shipping from around the world, so I’m in. kind of deep already. I bought a new skiff to put it in too…

Having trouble finding the Trusted Builders link - but I’ll dig around some more.

Thanks for your support! I really appreciate it. Kind of a tough situation - since I didn’t build it - and I don’t understand the design enough to effectively troubleshoot it myself.

All the button LEDs are working. Everything else seems to be working - though the tone seems a little different than sample videos I have seen.

I bought this from a guy in Italy and had it shipped from Naples. Paid a good bit for it, plus shipping from around the world, so I’m in. kind of deep already. I bought a new skiff to put it in too…

I am in the SF Bay Area. I can’t find the trusted builders list, looks like it may not be posted anymore. I talked to a friend who works at the Synth Museum in Oakland, and he said he didn’t think any of the local techs would be able to help, since this has been out of production and there is limited support for it.