Beavis Breakout Box Woes

[slacker]

You could be on to something there Rob, possible horse meat contamination?
This is one of the weirdest debugs ever, we appeared to have established that the switch was working a while back now it seems it's not.
Possibly a dumb question, but are you sure you haven't got the wires from the switch to the in and out on the terminal strip the wrong way round? This would explain why the switch seemed to work when you did the tests jumpering the in and out, but not when connected to a circuit.

[Jdansti]

Dang - I forgot to ask about the sausage!  

One of my cousins was an EE for Texas Instruments in the early 80's.  One of his responsibilities was helping business customers over the phone to troubleshoot problems with their "hi-tech" TI equipment. He once told me that the first step was making sure the device was plugged into the wall.  The second step was making sure the power switch was on.  The steps went in the order of simple to complex.

I'll have to ask him if he ever asked his customers about sausages.

[audiolife]

 

In answer to your questions JDansti:

Does the LED turn on and off now when you toggle the bypass switch? YES

Do you get a normal signal in bypass (LED off)? YES

Do you have the sag pot connected as shown on the Beavis schematic? NO

Is the SPDT switch only connected to the two designated screw terminals and nothing else? YES

@Slacker, yes I'm sure that I have the In/Out arranged correctly on the terminal strip.

[Jdansti]

Good

1) Without changjng anything, measure the voltage at the power terminal screw with the bypass switch on and off.

2) Now only disconnect the wires from the breadboard to the in/out terminals leaving the power and ground connected to the breadboard. Place a jumper wire between the in and out terminals. Leave the power going to the Beavis Box on. Measure the voltage at the power screw with the bypass switch on and off.

3) With the same configuration as #2, do you get a full, clean signal with the bypass switch on and off?

[slacker]

Nice one John, we're close now I can feel it, hopefully 2 or 3 fails miserably, cos I'm completely out of ideas if they don't.

[audiolife]

So I tested everything JDansti suggested and it measured out just fine. Tried hooking up the other jacks and battery power, fuzzed out like a charm.

This whole time I had been testing the battery power on the side of the breadboard with the circuit, bypassing the jumpers from the other rails. I thought to myself to try hooking the battery up on the other side and jumpering to the side with the circuit...

BINGO! There was the problem. Not sure what the hell was going on, but that was the culprit. I pulled the jumpers, put them back in and tested the box with wall power and battery. Worked great! 

Clean bypass, fuzzed out when engaged. I A/Bd this with the sound of the guitar just going into the amp to match tonalities and level imbalances and everything seems to be working fine.

I don't want to get a head of myself as I've still just tried Dead Astronaut's fuzz but it seems that we have finally solved this issue.

It's always in the last place you look! 

I'm gonna try out some other circuits and see what I can get!

[slacker]

Nice, glad you got it working, now get building something cool on it

Any chance you could post us photos of how you had the breadboard hooked up when it wasn't working and how it is now it works? I'd just like to try and understand what the final part of the problem was.

[Jdansti]

Yea!!!!

[deadastronaut]

cool so it works yayyyyyyyyyyyyyy....whoooohooooo.......


so it was your power rails (needing jumpers)  then?....  e.g. to get continuity (beep) across left to right on both?.



fuzz face to try too...

https://dl.dropbox.com/u/7464107/SILICONFACE1.jpg