orange squeezer zero voltage

[peterg]

I've built an Orange Squeezer and my multimeter shows 0 voltage everywhere - actually 0.001 at the + power input. I've checked all the traces and solder and all looks good as well as checked the layout for issues numerous times. Before I start de-soldering everything I'm hoping to pinpoint the possible issues. I added a 1N4001 as polarity reverse protection - it is the right way. It could be blown since I hooked up by power backwards when testing the circuit  Other than that I can only think of a fried Jfet - they were salvaged from an old project.

Any input would be apprieciated.

[petemoore]

  Disconnect the battery, Check for a direct short across the power rails.

[karbomusic]

I've built an Orange Squeezer and my multimeter shows 0 voltage everywhere - actually 0.001 at the + power input.

That makes it sound like it isn't actually receiving power or is shorted. Probe before the protection diode and also see if the diode, power supply or batter are getting warm/hot such as a direct short. Or just remove the diode. You gotta at least have 9V at the power input pin. Until you have that, I wouldn't move a mm beyond that point because that's where the problem is.

[petemoore]

 Yupp, .tiny amounts of Mv does sound like maybe open, that or shorted.
Once we know what the scenario is there, it's just a matter of finding where the problem is.
It's simple to trace through and find an open.
Finding a short is more challenging, I like to start into a magnifying glass at the circuit under a close-in high intensity lamp.

[peterg]

Thanks guys. I have probed the power + and - at the power source and the board and get the reading mentioned. I used my Boss wall wart to test it. The wall wort works. I'll try with a battery to check for heat.

petemoore: when you state " It's simple to trace through and find an open." does that mean a point where the power trace is cut?

[petemoore]

 Don't connect the power supply or battery if shorting a condition is found across the circuit rails..
Shorting the battery puts high load on the connection, battery, and any components caught up in the action to high current/heat, if not diode protected it's instant catastrophe, otherwise the diode might sacrifice itself before exposing the circuit components to RP..
Once the short circuit is found and opened, and the rails are sorted out, connecting the circuit rails to the battery, everything fares better..I like to check battery voltage drop to determine load right away though.

[peterg]

 I found a number of unwanted traces which I fixed so now have sound. There is a loud h um though. Voltage readings are:
Q1 - drain 9.35   
Source - 2.18
Gate - 1.61 set by trim pot
Q2 - drain 1.61 (same as Q1 gate and Q2 source)
Source - 1.61
Gate - 0.20

IC -1 - 5.1
2 - 5.14
3 - 4.24
4 - 0
5 - na
6 - na
7 - na
8 - 9.35

Any ideas anyone?