Anushri breackdown (no sound from audio out, but drums are ok on "modular" out


My Anushri was working a few days ago, but I manipulate him a lot because I was making his case. and now as the case the finish, anushri doesn’t work anymore :((
There is no sound from audio out, but I can still use the drums, I can see that he received midi.
At voltage test the green points show 0.77v and point 3 : -2.3
my psu is 9V (+inside). all others are ok…

do you know where to start?

Excessive voltage from your PSU having blown the LT1054?

Which voltage do you have on each sides of the 1N400x diode?

I have never used more than 9V psu… (and I don’t have to use so often the anshri since I have finished it).

The volatge of point 1 : 9.61V
of point 2 : 8.8V

Thanks for you 3 min answer!

Some PSUs cannot be trusted and output sharp transients when they are plugged in.

Try to remove all ICs (except the LT1054) to eliminate the hypothesis that one of them got damaged/shorted. Do you still have something wrong with the -5V rail?

After removing ics (expect LT1054) I Have correct -5V everywhere,

at point 3 I have -5.7V.

Is that what you expected?

Yes… Try inserting the ICs one by one until you find at which points it causes the voltage to drop.

Heu I found something very strange :

I turn on anushri without ics except lt1054, so all the green point show ; 0.7V, if I touch with my probe the 2 legs of the 7905 (point 3 and green point) at the same time then all the green points turn to -5V,

is that normal?

And if i do the same trick with other ic the voltage decrease

Do you think that mean that the LT1054 is dead?

I have kind a same thing. Drums are ok on outputs, but synth gives no sound. I see midi led blinking. I did step by step assembling without testing or calibrating. Time to start probing?

So far all voltages are good…

Heikki, Are you sure the 6n137 is in right position?

do Somebody know a way to check LT1054?


I think I found one :

Mine is working! I was lucky and found a solder bridge between one IC-socket and the board.

I have changed the LT1054 but the problem is still the same (now I use only 7.5 PSU), Is it possible the problem come from a bad solder somewhere?