e-licktronic wrote: Accent is not a trigger signal: it is a control voltage to set the velocity of each voice.
You must connect 5v to get higher velocity on IC23 pin5

Best regards,
e-licktronic

Thanks Vincent.

Ok, so.

This is how I'm doing it.

1. PSU - Plugged in and supplying power to the entire main board.
2. Doepfer DarkTime supplying +5v trigger pulses to MT trigger point

This is how I triggered the MT voice and then scoped all points on page 1 of this post.

I need to;
1. PSU - Plugged in and supplying power to the entire main board.
2. Doepfer DarkTime supplying +5v trigger pulses to MT trigger point
3. +5v trigger pulses or constant 5v to IC23 Pin 5? I'm afraid to connect +5v to the IC in case I blow it...

Also,
I've tested continuity between GND and Pin 14 of IC22. No continuity. In fact, not one pin from IC22 is connected to GND. Does that mean my problem is not the GNDing of the VR14 stand off mentioned by Comboy in this post viewtopic.php?f=24&t=832&start=40#p4781?

R12A is also not connected to IC22 (4069) pin14. I can't see properly on the schematic if it is supposed to be connected. 909 and Nava Schematic are unclear for this connection.

Thanks

Did some more tests;

Checked voltage at IC22 Pin14 and attenuated VR13, -10.18v to -11.07

Horizontal & Vertical Plains EG...


IC22_pin2 (Scoped with +5v Voice Trigger)


IC22_pin4 (Scoped with +5v Voice Trigger)


IC22_pin8 (Scoped with +5v Voice Trigger)


Q30_Base (Scoped with +5v Voice Trigger),
-4.21v (Voltages with Meter taken with no +5v on Voice Trigger), 2.91m to GND with meter


Q30_Collector (Scoped with +5v Voice Trigger),
+14.09v (Voltages with Meter taken with no +5v on Voice Trigger), 21.8k to GND with meter


Q30_Emitter (Scoped with +5v Voice Trigger),
-10.21v (Voltages with Meter taken with no +5v on Voice Trigger), No reading (0.L) to GND with meter


R132_10k_Lower_SIde_Componant_Side (Scoped with +5v Voice Trigger),
+14.16v (Voltages with Meter taken with no +5v on Voice Trigger), 12.14k to GND with meter


R132_10k_Top_SIde_Componant_Side (Scoped with +5v Voice Trigger),
+14.09v (Voltages with Meter taken with no +5v on Voice Trigger), 21.9k, to GND with meter


R134_47k_Lower_SIde_Componant_Side (Scoped with +5v Voice Trigger),
-10.51v (Voltages with Meter taken with no +5v on Voice Trigger), No reading (0.L) to GND with meter


R134_47k_Top_SIde_Componant_Side (Scoped with +5v Voice Trigger),
-10.24v (Voltages with Meter taken with no +5v on Voice Trigger), No reading (0.L) to GND with meter


C32_18n_J_Bottom_SIde_Componant_Side (Scoped with +5v Voice Trigger),
100-200mV (Voltages with Meter taken with no +5v on Voice Trigger) , 12.14k to GND with meter


C32_18n_J_Top_SIde_Componant_Side (Scoped with +5v Voice Trigger),
+14.17v (Voltages with Meter taken with no +5v on Voice Trigger), 2.9r to GND with meter


Any ideas?

hofmann25,

On IC22 pin2,4 and 8 you should scope a perfect square waveform.
On IC22 pin14 you should measure between 1.5 to 3.50v (more or less 10%) by moving VR13

Measure on VR13 pin2 with your DC Multimeter ?
Is D34 a 1N4746A Zener diode ?

Best regards,
e-licktronic

e-licktronic wrote:hofmann25,

On IC22 pin2,4 and 8 you should scope a perfect square waveform.
On IC22 pin14 you should measure between 1.5 to 3.50v (more or less 10%) by moving VR13

Measure on VR13 pin2 with your DC Multimeter ?
Is D34 a 1N4746A Zener diode ?

Best regards,
e-licktronic

Ok some interesting test results. The voltage at IC22 Pin14 while attenuating VR13 was -10.18v to -11.07 with the Doepfer Darktime's Gate out (Sleeve to GND & Tip to MT Voice Trigger point) supplying +5v Trigger Pulses.

But before connecting the darktime I powered the main PCB with the PSU and measured IC22 pin14: +13.73, no change while attenuating VR13.

I then, connected darktime and started the sequencer. Voltage on IC22 pin14 went from +13.73v to -10.18v! To get IC22 pin14 to measure +13.73 I had to disconnect the PSU and touch C90 to decharge the cap then connect the PSU again and IC22 pin 14 went back up to +13.73! Otherwise IC22 pin14 kept measuring -10.18v even with the darktime disconnected!

On IC22 pin2,4 and 8 you should scope a perfect square waveform. No, see images below (Images taken with +5v Trigger to MT Voice Trigger point)

IC22 PIN4:
Wave Max = -3.649v // Wave Min = -10.28v. 24uV/us
Cycle Start = 546ms // Cycle End = 270ms. 3.623 19 hz


IC22 PIN8:
Wave Max = -4.297v // Wave Min = -10.79v. 23.5uV/us
Cycle Start = 546ms // Cycle End = 270ms. 3.623 19 hz


On IC22 pin14 you should measure between 1.5 to 3.50v (more or less 10%) by moving VR13 No. See above.

Measure on VR13 pin2 with your DC Multimeter ? +1.668v > +3.51v.

Is D34 a 1N4746A Zener diode ? Yes and was tested before installation. Polarity is correct too.

hofmann25,

Unsold IC20 and measure VR13 pin2 voltage. (only Nava PSU connected)

Best regards,
e-licktronic

e-licktronic wrote:hofmann25,

Unsold IC20 and measure VR13 pin2 voltage. (only Nava PSU connected)

Best regards,
e-licktronic

+1.668v to +3.52v

Thanks Vincent

Think I found the problem! Was hard to find but stoked!!!

I was going through the MT circuit checking continuity between connections on the schematic and got to the connection between R12A and IC22 PIN14. No connection! Now this bloody connection is made with 3 components and 3 Via's (Or something )!

Seems the old Via under VR14 that caused a lot of problems for others and their MT is causing me issues. But not the same...

When I was probing (To see if that via was connected to the VR14 standoff) a few days ago I must have destroyed the via on the component side where it joins the trace and D34 (1st component in-between R12A and IC pin14 ).

Because I'd fixed another trace previous to this the MT wasn't working anyway so the problem just seemed the same and I didn't know I'd destroyed the via.

Check the photos below;

The circled via (Red and Green circle) is where the connection is lost (You can see the via looks a bit bigger than the others). The other red circles are the other points that make up the connection between R12A and the broken via.



Bottom side and VR14. Circled on the left is where the via comes out on the bottom of the PCB and circled on the right is the other end of the trace and the pin it should be connected to on IC22. (I've re-flowed all the solder points of the MT, thats why all my soldering looks shabby and I can see I bent a component leg and solder above the via when I was bending VR14 standoff)



Circled on PCB Bottom and Top Layouts.



Now I have an idea on how to fix it. Using a resistor leg pushed through the via (I have already tried it and it fits). Then scratch off a bit of the paint over the trace on each side of the PCB and solder the resistor leg to each side (Ive bent the VR14 stand off out of the way).

Now my question is; is this the right course of action? Once I make this solder I'd say it would be a kharnt to de-solder this resistor leg out/off!

Should I do it Vincent?

Should I do it Vincent?

If you think it will solve your issue, of course do it

Best regards,
e-licktronic

e-licktronic wrote:

Should I do it Vincent?

If you think it will solve your issue, of course do it

Best regards,
e-licktronic

I don't know that it will solve 'the' issue but R12A is supposed to be connected to IC22 pin14 right?

This is just me trying to read the schematics. IC's are a bit harder to read on a schematic...