Mindbender NPN (Tonebender MKII) Problems

[pete27]

Hey guys,
So im at the debugging stage for a Mindbender NPN (as at: http://fuzzcentral.ssguitar.com/mkII.php) and all i get is a very gated sound when i turn the amp up VERY loud and strum hard. So i figured my biasing is off.
Reccomended voltages are:
Q1 Vc (hfe=70) 8.11V
Q2 Vc (hfe=70) 1.10V
Q3 Vc (hfe=100) 4.5V

My voltages are:
Q1
C = 8.3
B =0.05
E =0

Q2
C=1.45
B=1.35
E=1.42

Q3
C=1.38
B=1.45
E=1.3

The 20k trimpot doesnt help with adjusting Q3 at all, so i figure theres something wrong with my biasing of Q3 and possibly Q2 also doesnt seem right because the collector and emitter are almost the same?
Ive checked all the resistor values and they are all ok.
Im using 2n388's purchased from smallbear.
Does anyone have a better idea as to where i should look to solve my problem?
Thanks very much

[tubelectron]

Hi,

I have built a TB MkII professional with no significant differences with yours, regarding your problem, with 3xOC72 and no trimpot.

I didn't faced this problem, as my TB worked OK at the first pluck. My transistors have an hfe=50 (Vcc=9V, Ib=10µA) and Ice0=100-150µA.
What about yours ? Are you sure there are all OK (hfe and Ice0) and installed with no pinout mistake ? Or maybe another "stupid bug" somewhere stopping the transistors from working correctly ? It happens to us too often...

Moreover, I found that the TB MkII works better when the attack pot is fully maxed (= shunted by the by-pass cap), controling the overdrive through the guitar pot : the overdrive decay is way better.

A+!

[Toney]

 Check Q1 base resistor value, cap  orientation and solder bridges/shorts.
Quadruple check your off-board wiring.
Also, make sure you're sure about the pinouts. Dot markings on Ge's can be either collector or emitter, case by case.
Really it's a booster whacking a Fuzzface, so you should get it going quite quickly.