So, I just built the anushri and everything is working fine and dandy but the square wave (sub squares work). The mixer pot just fades out the saw wave, I already switched around the TL074 with the other one which made no change. I also checked the PW pot for shorts and it works fine as well. (-5 0 5 in center pos.) I’m really lost for ideas at the moment, any help would be greatly appreciated.
"-5 0 5 in center pos"
What unit are talking here? V ? Ohm ? Amps ?
Volts on the pins, left to right measured on the frontpanel.
Have you soldered the 3.5mm jacks on the control board?
I have soldered them all in place, I’ll check them all again once i get home today, but they should be good as far as I’m concerned
Checked them all again, brushed up some solder joints, still not working.
What are the voltages on IC9 pin 7 when the pulse-width pot is in minimal and maximal positions?
Maximum clockwise: -3.28v, maximum ccw: 3.3v
Can you hear the square wave at IC10 pin 7?
Nope, I don’t get any output there it seems, got nothing but a little hf noise on the scope.
What’s going on at IC10 pin 1? If you have a scope, capture! Otherwise, could you please measure with your meter in AC mode and in DC mode
This is the plot of IC10 pin 1, IC10 pin 7 has nothing happen but a very low frequency curve (similar to a capacitor charging/discharging, exponential rise/fall) when I connect/disconnect the probe, sadly I can’t record with this setup so only momentary plots.
Your scope input is AC coupled or DC coupled?
I think it is AC coupled, but I’m not 100% sure to be honest, don’t have schematics or anything in the manual giving a pointer.
The pin 7 of IC10 is at -3.3 volts DC and 0 Volts AC.
I want to know these for IC10 pin 1.
I’m sure that that is the measurement I’m getting, just negative DC voltage on the pin, doesn’t change if I switch the TL074s around, the filter works either way though.
IC10 pin 1 got 0.16VDC and about 1.7 VAC.
This is weird… Everything that’s fed into IC10B is correct. Check for all the solder joints on the IC socket. Check that IC9 pin 7 is continuous with IC10 pin 6. Check R73.
In last resort, can you try adding a small cap (say 22pF) between pin 5 and 7 of the op-amp?
I checked all the solder joints, there are no shorts, I don’t have anything smaller than 22nF cap on hand atm, would it suffice or should I order one? It really baffles me as to what could be wrong with the assembly/board.