Assistance needed with Aion Refractor (Klon)

[antonis]

Are you sure for not shorting IC pins with DMM probe..??

[CasWalker]

Are you sure for not shorting IC pins with DMM probe..??

If tried multiple ground spots and am getting the same results. I guess it's possible, but I don't believe so.

[antonis]

I mean with RED probe.. The one in conduct with IC pins..

P.S.
Do you put the probe on solder side of board or directly on IC pins..??

[CasWalker]

I mean with RED probe.. The one in conduct with IC pins..

P.S.
Do you put the probe on solder side of board or directly on IC pins..??

On the pins.

[MrStab]

Likely a problem with R2, R29, R30, C18 or Vref trace (if probing correct). C1 dead/shorting and passing DC possibly. Perhaps slight negative offset from 0V is a clue.

[antonis]

I'd insist for IC1 malfunction..

Without IC1 in socket, non-inverting input (pin 3) exhibits 1.56V which is severely loaded (0.48V) with IC1 in place..

[MrStab]

Since IC1 and IC2 are the same chip, I took the one I measured out and put the other one in the IC1 slot and got the same readings.

Unless some power rail error is instantly frying all ICs?

BTW have you tried op-amps from a different supplier? Those TL072s look a bit "interesting", but maybe it's just the angle and lighting.

Curiously, NC pins (6 & 7) on IC3 seem quite far off what the guide suggests, while the rest is within a reasonable(ish) margin.

[CasWalker]

Since IC1 and IC2 are the same chip, I took the one I measured out and put the other one in the IC1 slot and got the same readings.

Unless some power rail error is instantly frying all ICs?

BTW have you tried op-amps from a different supplier? Those TL072s look a bit "interesting", but maybe it's just the angle and lighting.

I don't have any others on hand to try, will have to order some.

Curiously, NC pins (6 & 7) on IC3 seem quite far off what the guide suggests, while the rest is within a reasonable(ish) margin.

[CasWalker]

I'd insist for IC1 malfunction..

Without IC1 in socket, non-inverting input (pin 3) exhibits 1.56V which is severely loaded (0.48V) with IC1 in place..

But with both ICs of that value getting the exact same readings, I'm not sure.

[MrStab]

Could you plz take IC1 & IC2 out of sockets and take measurements on respective pins 3..??

IC2 - 4.67

...Vref is fine, I was talking rubbish. Sorry. That pin is connected directly to Vref.

Are you sure those chips don't say TL071? Can't see a clear shot. Usually even counterfeits work to some extent, with the ubiquity of dual op-amps!

Clutching at straws probably, but the spacing between "7" and "CP" doesn't look like it'd comfortably fit a "2". lol

[CasWalker]

Well yup, they are TL071s, not TL072s. I believe you found the issue....

Checking with the vendor as this was a prepackaged kit...

[Slowpoke101]

In the clearest image showing IC1 it is definitely marked as TL071CP. A small ball of solder is just over the 1 making it very hard to see. I cannot resolve any markings on IC2 at all - either out of focus or obstructed.
The question is - the voltage on IC2 looked OK but IC1's did not. Of course it did not, it can't as a TL071 cannot work in that circuit but did not the OP put IC2 into IC1's socket and test those voltages again?
I suggest that that the OP just get some more TL072 op-amps, put them in and try again. Just remove all doubt about those chips.

And I see that the OP has beat me to it. Great the You found the problem. 

Edit: Oops. Quick review of posted IC2 voltages shows that they too were all over the place. Once again proving to myself - read the whole thread before making an idiot of myself. That way I can do so more efficiently.

[CasWalker]

In the clearest image showing IC1 it is definitely marked as TL071CP. A small ball of solder is just over the 1 making it very hard to see. I cannot resolve any markings on IC2 at all - either out of focus or obstructed.
The question is - the voltage on IC2 looked OK but IC1's did not. Of course it did not, it can't as a TL071 cannot work in that circuit but did not the OP put IC2 into IC1's socket and test those voltages again?
I suggest that that the OP just get some more TL072 op-amps, put them in and try again. Just remove all doubt about those chips.

And I see that the OP has beat me to it. Great the You found the problem. 

Edit: Oops. Quick review of posted IC2 voltages shows that they too were all over the place. Once again proving to myself - read the whole thread before making an idiot of myself. That way I can do so more efficiently.

Aion acknowledged they did send out the wrong ICs, so the correct ones are in the mail. Hopefully that resolves it.

[Slowpoke101]

I see that Aion is going to send you some TL072 chips. That's great. Hopefully it will not take too long for them to arrive and you can get back to your effects pedal build.
Meanwhile if you have any other builds awaiting your attention now would be a great time to make a start on one of those. Anyway, let us know what happens when the chips arrive and you test the Refractor. Hopefully all will be well.

[CasWalker]

I see that Aion is going to send you some TL072 chips. That's great. Hopefully it will not take too long for them to arrive and you can get back to your effects pedal build.
Meanwhile if you have any other builds awaiting your attention now would be a great time to make a start on one of those. Anyway, let us know what happens when the chips arrive and you test the Refractor. Hopefully all will be well.

Will do. Thanks everyone for your help!

[antonis]

It now really makes sense..

By using TL071 is such a configuration, it effectively connects Offset null (pin 1) to Vref via 2M resistor, which results into a Vref->2M->1k3->GND so voltage on non-inverting input (pin 3) is set by (Vref * 1k3) / (2M + 1k3)..

[CasWalker]

Received the replacement ICs today. That was definitely the issues. Works great now. Thanks everyone for your help!