EQD Interstellar Orbiter on Vero sounds like two ambulances (help)

Started by Ad, May 06, 2022, 05:01:22 PM

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Ad

I built the orbiter on Vero from a layout on dirt box layouts and it fired up first try exceeeept if any res. a,b int. a,b or even freq pots are turned up past somewhere around 10% I get a solid, consistent ambulance sweep. There is also a slight distortion in the dry signal when cranked up. I have went over this build 5 or 6x checking component placement and orientation to no avail. it seems all pots are working as they should except for the obvious. it almost seems as if I have a incorrect value component somewhere but if that were the case it would not be doing it on both filters corrrect?? Another thing that strikes me as odd is one filter seems significant louder than the other. I have checked all values on resistors and caps and I tested them BEFORE soldering in. I have limited knowledge of electronics except a few books I have read and some youtube courses. All components used are what were called for. I did have to series two resistors to make the 390K resistors. I've went over my solder joints, checked wiring, placement/orientation and I've tried diff. ICs. I bought some custom boards from JLPCB and the holes are plated on both sides, the vero tracks run on the bottom and are masked. This is my first build with these boards. Thanks in advance for any advice or help. Will post pics of my build from phone. Just to specify, I do get dry signal and when res, int, and frequency pots are almost off I do get effect signal. the rate pot also works as it should.

IC 1
1, 8.96
2, 8.96
3, 9.41
4, 9.41***
5, 8.93
6, 8.97
7, 8.96
8, 9.42***

IC 2
1, 8.94
2, 8.93
3, 9.41
4, 9.41***
5, 9.41
6, 8.92
7, 8.94
8, 9.42***

IC3
1, 8.94
2, 9.06
3, 9.41
4, 9.41***
5, 9.41
6, 9.39
7, 9.40
8, 9.42****

IC4*****
1, 9.88
2, 10.0
3, 9.91
4, 9.81
5, 9.41
6, 8.97
7, 9.40
8, 9.41

Q1
E 9.62
B 9.39
C 8.97
Q2
E 9.41
B 9.40
C 8.98
Q3
E 9.41
B 9.41
C 8.97
Q4
E 9.41
B 9.41
C 8.98
















antonis

Could you check for both R4 & R14 grounding..??

On a second though, it seems like no circuit GND is connected to power supply GND..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Ad

If I'm reading it correctly r4 should be one of 10K res I marked with red and I do have ground there. R14 I believe, I marked in white and do not have a connection to ground.


bluebunny

Quote from: antonis on May 06, 2022, 05:46:01 PM
On a second though, it seems like no circuit GND is connected to power supply GND..

^^This.  Antonis means that you don't have a ground connection at all, anywhere on your circuit.  Please check for continuity amongst all your "GND" points and the -ve power supply (I can't see in your pictures how the power enters your build).
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Ohm's Law - much like Coles Law, but with less cabbage...

antonis



Check both R4 & R14 red circled legs for continuity to GND (all the green line till green framed Ground)

If both the above are OK, then check any point on white lines..
They must measure a little bit lower than half of your power suplly voltage..
(both due to Scottky input voltage drop and your DMM's internal impedance..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Ad

sorry my pic in my last post was cropped. so I tested everything you said and all the grounds were good and all white paths were at 4.4 - 4.5. I seem to have ground on my ics now. all pin 4 are at 0v. here are my voltages again. still getting siren on both filters. sorry for delayed response wife, kids mother day activities.

ic1
4.4
4.4
4.4
0
4.1
4.4
4.4
8.9

ic2
4.4
4.4
4.4
0
4.4
4.4
4.4
8.9

ic3
4.4
4.4
4.4
0
4.4
4.4
***this pin is fluctuating all over the place. anywhere from .5v - 6.0v definitely an issue here.**
8.9

ic4
***this pin is acting a lot like pin 7 on IC3 with diff voltages.**
4.4
fluctuating
0
4.4
4.4
fluctuating
8.6

**ic3 pin7 and ic4 pin1 are fluctuating but its almost as if my multimeter is reading the voltage then gets no voltage and then reads a diff. voltage. its not a normal fluctuating voltage where it just reads one voltage after the next. never seen this before

ic4 pin3 an pin7 are your normal fluctuating one voltage followed by another. sorry if this is confusing kind of hard to explain.

q1
e 0
b 0.7
c 0

q2
e 0
b 0
c 0

q3
e 0
b 0
c 0

q4
e 0
b 0
c 0

anotherjim

Yes, 3 of the opamp output pins should fluctuate. They are modulation LFO signals. The Rate contol should adjust the speed.
You need to twiddle some controls. It is possible to set the transistors to off by the intensity controls hence 0volts on the base terminals.
The design appears to have two resonant filters. It may be intentional that they can self-oscillate if the Resonance controls are turned full up.

Ad

I'm getting fluctuations on two of the op amps but not three and the rate control seems to somewhat dial in the lowest voltage that the pins will hit. I understand what you mean about self oscillations but both filters will cut any guitar signal and oscillate anything past 8 o clock or "1" if numbered out of ten.For me to get any signal (except dry) it has to be dialed in absolutely perfect and even IF i find it if i strum even moderately hard it turns into a siren again. I also tried turning mix, res, ans intensity knobs while checking Transistors voltages and no luck. Still at all 0s. I will take them out and test them and maybe try bypassing the exp inputs.

anotherjim

On the schematic, IC4 is the LFO. Pin1 switches between high or low voltages at the speed set by the rate pot. Pin7 sweeps gradually between high and low at the same Rate as pin 1. IC3 pin7 creates an inverted copy of IC4 pin7 so you have two LFO modulation sweeps going in opposite directions. One filter sweeps up while the other sweeps down.
Of the transistors, Q1 & Q2 set the filter centre frequency according to the control voltage from the Frequency pot (this can be an expression pedal?). The Frequency pot wiper ought to provide enough voltage for transistor bases so I'd check what you get for the full sweep of that pot.
Q3 and Q4 provide similar control for the LFO modulation. The opamps supplying the intensity pots should probably never sweep down to 0v (the opamp types used can't output lower than about 1v-1.5v) so again ought to provide enough control but the lowest setting of those pots will take the transistor bases down to 0v providing an "off" switch for the LFO modulation.

It all points to something wrong with the pot connections to me.

Ad

I appreciate the explanation. I have been studying reading schematics and electronics basics but the design is definitely above my pay grade. I'm pretty good or "lucky" at the paint by numbers Vero builds but the 8 knob, dual filter, exp. inputs all on new boards with plated through holes has got me stumped. I'm not the best troubleshooter either but usually I can figure it out if it comes down to that. I've tried all the usual suspects but I have not tried anything with the pots other than seeing if they do what they are supposed to. ill give that a shot and see what I get. I did take out a couple trans and tested them and they tested ok. I also removed the exp. inputs but have not had a chance to test them it since I removed them. sorry for the delayed responses. (mothers day, wifes bday, and 3 kids) ill give the pots a try. thanks for the response.