Deadringer problems

[2tonewarrior]

I am getting mad. I've build a deadringer I set aside moths ago because it didn't work. I've seen it and I decided to get it work so I've rewired all (I thought the problem was there) and It still don't works.

I've checked all. The values are ok (resistors, pots, caps, ...). The wiring is a mess but I double ckecked it and it's ok (see the photo below, taken with phone. I´ll take something better if you need it). OpAmp changed by a new one (just in case, same with the switches, except 3pdts, leds and DC jack). Checked the ppolarity of electrolytics, diodes,...



(I´ve changed the boost pot to the left)

The sound works good through bypass but I can get any sound besides a big HUMMMM when the effect is on. The leds are not even working!

And finally, I get ridiculous voltage readings on IC and transistors

Power source : 9,5V

IC1

1: .041
2: .042
3: .025
4: .042
5: .036
6: .036
7: .037
8: .049


Hope you can help. If you need more information only say it.

Thanks

[gtr2]

At the very least you should have 9V at pin 8 on IC1.  Somewhere your shorting to ground.

Josh

[gtr2]

Check for solder bridges.

Josh

[2tonewarrior]

Checked it before wirign but i´ll check it again.

[mgwhit]

At the very least you should have 9V at pin 8 on IC1.  Somewhere your shorting to ground.

And you should have 0V on pin 4.  We're going to need to see the back of your board.

[2tonewarrior]

Partially solved. Micro bridge between 9V and Ground   . Now sounds, have minor problems with some pots but I think I know where is the problem. I´ll check later and tell if it´s complete solved. Thanks both, you can check one thing 4 times and only see the problem the 4th...

[2tonewarrior]

Ok, checked and I´ve no idea whats happen with gain pot. Same problem as here

I´ve used a 250k pot instead 500k for more difference between gain and boost as shown in the build docs but the gain pot does nothing

[mgwhit]

Both the Gain and the Boost are implemented in the same feedback loop, so if Boost works, but Gain doesn't, it's probably a wiring problem.  It could be a bad pot or a bad switch, but let's not go there yet.

What happens when the Boost is deactivated?  Is there any amplification or distortion on the signal.  Or is there no signal at all?

When the Boost is active, does the Gain knob affect the signal at all?  This might be easiest to determine with the Boost knob turned all the way down.

[2tonewarrior]

The gain pot doesn´t change the sound when the boost switch is on or off. Without the boost there is a smoothly gain. The boost works but increases the volume A LOT, I don´t know if it is right.

Volume and Tone pots seems to work properly.

[mgwhit]

So signal is getting around or through your Gain pot, but if it's going through there's no sweep.  I would check to confirm that you wired the Gain pot correctly -- specifically that you connected the wires to lugs 1 and 2 and not 1 and 3.  Also, check that there isn't a short near the Gain pot wires, either on the board or on the pot lugs.

If neither of those turns out to be the problem, then go ahead and disconnect your Gain pot and test it with a multimeter.

[2tonewarrior]

I´ve checked the gain pot with a DMM and it´s working, wiring are ok too. I´ll desolder all pots and toggle switches to see the bottom of the PCB and I´ll reflow the pcb holes where pots are connected when I have time.

Also I´ll change the wire from solid core to stranded. I´ve been moving it a lot and can be semibroken at some place. It happened to me sometimes.

Thanks for the help

[mgwhit]

Keep in mind that signal has to be either (a.) going through the Gain pot and the wires leading to it (yet somehow not registering the variable resistance of the pot), or (b.) short circuiting around the pot (possibly on the traces near the wire pads, or even on the pot itself).

I'd do continuity tests with a multimeter before i suspected broken wire.  You can also probably test for continuity between lugs 1 and 2 with a multimeter to confirm that that is the problem.  Good luck!

[2tonewarrior]

I´ve checked the pots with the DMM and that was exactly the problem, a copper bridge I overlooked between 2 pads of the gain pot. I´ve checked all the board another time just in case.

I´ve encountered other minor problems. When the On-on-on switch is in the Vintage (Mosfet/silicon) the volume decreases. And I´m having the same issue with the boost (increases the volume a lot). Anyway the sound is good, only I have to pay more attention to the controls. I´m going to consider it done and going for another project. When I have time I come back to it and possibly etch a new PCB, I think most of this problems are caused by a bad etch.

Thanks, you have helped me a lot with this project! 

[nzCdog]

Hi... sorry this is way too late to the thread, but I have a working deadringer here... if anyone needs voltages.
There is a volume difference between Mosfet and silicon clipping anyway, so no problem there.

[2tonewarrior]

Well, the voltages definitely could help, I will be pleased if you can post them.