Aion Blueshift Chorus BBD Biasing

[Elvis Cocho]

Hello. I recently put together an Aion Blueshift Chorus which is a clone of the Boss DC-2 chorus. I ran into a little trouble when biasing the MN3207 chips. I plugged in 9VDC to the circuit without the bottom circuit board attached and I was able to get both chips to have 3.4V at pin 3 of IC9 and IC3. Now I'm trying to bias the circuit with a signal from my generator. I set it to 8kHz, 2Vpp. I was able to bias IC3 with the trimpot TR2, but IC9 doesn't seem to respond to TR1. I plugged in a guitar and it sounds like the pedal is doing what it's supposed to but I'm puzzled about the response from IC3. I followed the signal all the way to the capacitor at the compander chip pin 8 and everything seems to be in place with correct values. Does anyone have an idea what I should do about this?

[GGBB]

Sorry, can't help you.

But - is it just me or has anybody else noticed that there seems to be more build problems posted about Aion boards than anything else?

[EBK]

Sorry, can't help you.

But - is it just me or has anybody else noticed that there seems to be more build problems posted about Aion boards than anything else?

I've only noticed a high number of debugging posts with the Refractor (Klon clone).  Kevin makes beautiful boards that shouldn't be more problematic than other people's boards. 

The Blueshift is a very ambitious project.  It also happens to be very awesome once it is working. 

[PRR]

Welcome, Elvis.

> IC9 doesn't seem to respond to TR1.

You also mention IC3?

And "doesn't respond" means it is stuck at some voltage? What voltage is that??

Watch the voltage on the wiper of TR1 (or TR2). Should go zero to +7V. Now move to the other end of the 100K attached to the trimmer wiper. It should also go up and down just about as much. (A few mV shy due to meter loading.) If not, tell us what it does.

[Elvis Cocho]

Will do. What happens is that I can see a sine wave with my oscilloscope coming out of pin 3 on IC9 but when I move my probe over to the test point, i don't see anything other than a noisy line. I followed the schematic pretty closely and I know that the test point is exactly just after pin 3 on IC9, but physically I don't see anything with the probe. It's pretty weird. I did however make sure that I have the right value parts where they are supposed to be.