[dantheman13246@gmail.com]

As the title says: signal passes through the eqp501.  When I turn the wide pot on top of the unit the LED turns green and the unit shows that it is on.  I've looked over all solder joints many times, reflowed, and checked component directionality...same problem.  I checked the DC voltage to eliminate the possibility of the DOA being the problem. When I tried to send a 100hz tone through the unit and measure between 0V and TP1 or 2 I get no voltage (no matter how high the volume or low).  I am not sure what this means or how I might be able to fix it.  I'm so close! Any help is greatly appreciated!

Dan

[JPK]

Do you hear the relays clicking when you turn the EQ on?

[dantheman13246@gmail.com]

I do hear a quiet click when the unit is powered on and powered off.  I have the DOA inserted and light turns on.

[JPK]

Send a strong sine signal (2VAC across cold and hot) to the input and check if you get 1.3VAC on TP1.
If not the issue is in the input stage. Check solder joints and components value of R1...R9, C1...C9, U1.
Check the supply voltages presence (- & + 15V) on pins 4 and 8 of U1.

[dantheman13246@gmail.com]

I was able to send about 1.9VAC to input and measuring across 0V and TP1 got something closer to 0.2VAC.

In double checking the Setup Guide on Step 4: "DOA Check" I realized when measuring between 0V and TP2 the voltage I get is -2.5VDC rather than 0.  When I take out the DOA the measurement is 0.  Does this mean the problem is in the Op-Amp?

I am also not sure where U1 is or its pins 4 & 8.

[JPK]

Check again the VDC on TP2 after removing U1.
If the large offset is still there then the issue is in the DOA.
If not it is around U1a, R10...R16, C17.

[dantheman13246@gmail.com]

The problem was indeed the DOA.  I got a new kit and followed assembly meticulously.  EQ works now!  Cant wait for my next one...

Thanks so much.

[JPK]

Congratulations!