Issues with a build of Chuck's Cobalt Drive

[devilmollusk]

I've been through several iterations trying to build a version of Chuck's Cobalt Drive mod. This version is closest yet. I get signal through the first op amp stage, and the Q1is nicely balanced (~10mV at Q1-D). I get signal all the way through C2, and then nothing. There is connection from Q2->R3, but no audible signal. Also the reading at Q2 are really bizarre. I've tried a few different transistors (I'm using 2SK193s), and so far the readings at Q2 are G=221mv, S=412mv, D=1.86v. I've attached images of the schematic and the PCB layout. Any help would be appreciated!

 

[Chuck D. Bones]

The drain voltages on Q1 & Q2 should be about 8.4V because Q5-B and Q6-B should be Vcc - Vbe. Q5-C and Q6-C should be close to Vref.

Make sure the 2SK193s are oriented correctly, Did you test them before installing?

Make sure Q6 is 2N5087 and that it is making good contact in the socket. IC sockets are not the right size for transistor leads. The leads fit loosely and don't always make good contact.

We'll assume for the moment that the board routing matches the schematic exactly and there are no assembly errors.