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DEADRINGER 2 trouble, boost not working

Started by MIM#1, June 26, 2014, 02:02:04 PM

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MIM#1

Deadringer 2 de-bug
Hi, Im having a problem with this build for some reason. There seems to be a problem with the boost section as the boost footswitch does nothing when on, bypass signal when off. No led either. The overdrive section is working fine and all pots and mini-switches [except for 'cut'] are doing what they should.
The boost section 'cut' switch does nothing, as there is no signal with the boost engaged. I Swapped the boost 3pdt and that wasn't the problem. Any ideas on where I could start looking? I'll post a gut shot so maybe somebody will catch something that I'm missing. The 3rd footswitch will be a comp if I ever get this up and running!
So in summary
1] no signal with boost engaged
2] no led from boost 3pdt
3] no cut switch

MIM#1

#1
http://www.madbeanpedals.com/projects/Deadringer2/Deadringer2.pdf

Ok, I'm getting zero voltage on R31 R24 R25 R23 R29 R26 R30 R28 R27 , all part of the boost cirquit as far as I can tell. Being that I dont really follow schematics too well I dont know which of these come first and which are downstream in the circuit. Q5 and Q6 both have voltage and I'm able to set Q5 with the trimmer. Hope this helps narrow it down and point somebody in the right direction to offer suggestions.
Thanx!

madbean

I think you have measured incorrectly. You must have voltage across R31 in order to have voltage on Q5. Please check this resistor again. Some of the other components will not measure DC voltage because the DC is blocked by a cap, for instance C22.

Let's find out about R31 for sure. The enxt step would be to audio probe the drain of Q5 to see if the transistor is actually putting any signal out whatsoever.

MIM#1

You are correct...my bad :-[
new readings show only R30 R22 R24 and R26 with zero voltage
R31 3.9v
R27 / R28 .54v
R25 .47v
R29 3.7v

madbean

What color are the bands on the R31 resistor you used? Your voltage there is way, way off.

MIM#1

Sorry, I mistook it for R29 which is 3.8v. R31 is reading 8.4v   :-[

MIM#1

Got a gig to go and play, I'll check back saturday. Thanks for your help!!!!

MIM#1

#7
On a side note, just had a show with my SUNKING II as a boost after my OD-2r. Holy cow, what a great tone!  8)
I'll replace the OD-2R [maybe] with the Dead-ringer if I can bring it to life.  :D

MIM#1

So... any idea what could be causing the boost section to cut out the signal?

madbean

Have you tried audio probing any part of the boost? It seems like your voltages are okay. Specifically, you want to the output of Q5, and the input of Q6.

MIM#1

Unfortunately, I dont have an audio probe. It would be easier for me to replace any suspect parts.

MIM#1

#11
Would posting voltages of Q5 / Q6 help?