Power distribution of IC01

Hello dear community.

I finally finished building my Anushri! The drum section is working fine but I still have some problems with the synth part.
It seems that only some of the functions are working. The filter part, the Fuzz, the LFO and the ENV mod are working.
But i can’t get any Signal out of the Sub Osc.
Also I dosen’t hear anything if I try to tune the VCO.(Holding “Hold” and Press “Run/Stop”)

I’ve done the Power distribution checks and every voltage measurement piont has the right value. Only the “LM4040 voltage reference” at Point
"IC01" shows 0,32 V instead of 4,1 V.

Could it be that the part is broken ?

I haven’t checked the signal path yet because I thought, I should fix the power distribution first.

I hope you can help me. I checked all the Parts but can’t find any mistakes.

Thank You !

Could you post photos of your boards? Maybe you have soldered this part backwards, or soldered a wrong part (one of the transistors?) instead…

Here are the photos! If you need something specific I will make some more.
The Number on the Part (IC01) says :

22ME7YE
NFC41l
Tl

it is the same as on position “IC12” and “IC13”

Thank you for answering so fast!

That’s really strange. Can you check that one side of R9 is continuous with ground ; and that one leg of IC1 is at 5V (not the one with the colored dot on the diagram… the other one…)?This is strange anyway because IC1 is only involved with the CV output circuitry.

To figure out what’s wrong with the rest of the circuitry you have to look elsewhere. I believe the VCO doesn’t work at all…

I’ve checked R9 and it’s continous with ground.
Only the one leg of IC1 shows any Voltage (0,32V), the other ones doesn’t show anything.

Ok I will check every Part again. Do you think it’s helpfull to start now with the signal path tests ?

Sorry for my mistake, no pin of IC1 should be connected to +5V indeed… Maybe you should replace IC1 then…

> Do you think it’s helpfull to start now with the signal path tests ?

Yes!

Ok I ordered a new IC part.
Do I have to play tones on the Anushri to check the signal path ? Or can I check it just by switching it on and checking it with my Voltmeter ?
Thank You for the support !

It is recommended to play tones from a MIDI device; or use the hold function (see “Latch and hold, jamming without MIDI keyboard” in the manual).

Some parts of the circuit will be running without any MIDI input (such as the VCO), but it’s better to have a MIDI keyboard at hand since you’ll also be able to tell if the noises you hear are responding to the notes you play or if they are just background drones.

I’ve tested the Signal Path.
I don’t know if it is helpfull but the Voltages at the Pionts are:

A=2,68V Stable
B=1,9-2,5 V
C= 0,5 -2 V
D = 0 V (2-4V “on”)
E=4,91 V
F= 0,7V
G= 3,87 V
H=4,52V
I=5,3V (if SUBosc -1 is on 5,19V)
J=5,3V(if SubOsc -2 is on 5,19V)
K= -0,71V
L= 0V
M= 0V
N=0V
O=0V
P=-1,45V
Q=-1,46V
R=0,04V
S=0V
U=2,3V
V=0,34V

I can hear the DCO Signal at point “U” if I put some headphones on this point and connect it with ground.
This doesn’t work at the other VCOs (square and triangle). I doesn’t hear anything.

Also I’ve discovered this : If I press the board connector beside of IC1 toghether, I can the Signals of the Oscillator. The soldering of these connectors looks good, could it be that the connector Pins aren’t linked well?

> could it be that the connector Pins aren’t linked well?

Unlikely… maybe it would be worth redoing all joints.

The soldering on all off the minijack socket on the control board looks very bad. That could use a lot more solder. A lot of those connections are make/break connections in the circuitry of the Anushri. So if something isn’t soldered right there. It won’t work.

@Craigh_Rosetti
Looking at your pics you are located somewhere in the Münsterland™ ?

Haha, not bad detective, fcd72 ! :slight_smile: But no, I’m from München. You’ve seen the letter in one of the pictures? There are going to be elections for the mayor in Munich so I got some post from the elections office :slight_smile:

Ok I will do some resoldering and check again.
Thanks for taking the time to help me !

@Craigh_Rosetti
So you are even not german :wink: . If it would have been Münsterland id invited you to drop on by and i have look….

I’ve soldered the minijack socket, I resoldert the PIN-connectors there isn’t any improvement.
The new IC should come in a few days, but i don’t think it will fix all the problems.
I don’t know what to do next. Is there any possibility of getting help by an expert who looks at my anushri?