MK11 Tonebender (fist PNP build !!)

[analog kid]

"stick with the 47k on the tonebender schematic"
well that's the problem with trying to fix whatever my problem is! (*AND I CAN'T BELIEVE THAT IT'S JUST TOO MUCH LEAKAGE ON THE GE'S I HAVE IN THERE, BUT FROM WHAT RG IS SAYING THAT 'MAY' BE IT)
back to what I was saying, that's the problem , I CANT go with anything much higher than 22k and STILL get the Q2 Collector to come up above a few 100mV's and in turn allow the trimpot on Q3 to adjust to anything as low as 4or5Vlts.    I don't understand it.  BUT just as soon as I change that resistor from 33k to 22k the voltages come up(on Q2 C and Q3 B/C)!
SOMETHING is still wrong though, even then
Q3  C  4.6v Trimpot
      B  3.4v
      E  3.2v
Q2  C  3.4v
      B  80-100mV
      E    0
Q1  C  7.6v
      B  90-110mV
      E   0

so even with a resistor change that low Q3 Emitter as Well as Q3 Base and  Q2 Collector are still suspect and not looking right to me.
(By the way I also changed the 470ohm resistor to 1k like the Mayer mod thinking it would make up some of the Gain I'd lose on Q2 by going so low on the Q2 collector resistor. . So could that cause problems rather than help, and should I change it back??)

[petemoore]

For the 470? I leave a little bit long enough legs, above board, make it a 1k or so, then if I want to halve the R value I 'tag' a 1k across the 1k = ~500ohms...close enough either way for initial biasing purposes at least...1k's fine.
 No I'd have to say look again around the gain pot, test all over around Q2 try something else,  I had a tonebender like that...forget whappenned to it, I have boards around that had problems, then later when I'm bored, figure them out...
 Probably ag...anything...bad part [ya never know...I've fried 'em messin' around I think]...keep looking at the nodes. Who knows what it is, if that circuit is 'right' it should work for a day or so with no problems IME.
 Something is definitely causing bad voltages, at this point there is such a conglomeration of text about that board...I'm inclined to do a new, complete breakdown...look at the nodes, calculate the resistances...[pull transistors to measure what you can, lift one end of a resistor to remove it from the Cct for measuring...
 Try a different Emitter cap ?...could be anything and usually is. Finding the problem is easy...finding the solution may require, as in this case, alot more.
 I never want to be the one to say throw in the towel, but I found measuring each resistor just prior to installation, socketting transistors, using a trimpot, counting connections to be made at each node...
 Check all sets of adjacent lugs etc. set the DMM for beep, and test Q1E/Q1B for shorts, Q1b/Q1C also...then Q2E to Q2B...so on, and anything else that isn't to be connected.
 Looks simple, theres a hundred things that can be checked...
 If you want to take it slow, PM me, and I'll ask one question per post...like whats the measured R value between Q1C and the top power rail...otherwise it gets ahead of where I'm at on it.
 Some of the time if the resistor is near the right value [like Q2CR or the 100k feedback R or the 470ohm...] you'll get a bias thats at least near or in the ballpark....IF everything else is close to right...like the Electro cap works, and is in the right way [in your case with PNP POS GND that would be + faces down connects to Gnd.] the 'main' bias resistors [those on C's B's and E's] are providing the right conditions for bias.
 Transistor pinout...lol...a little late, I forget if that got verified...Collector [top] base [middle] emitter [bottom] I think your'e transistors have a tab on the side of the hat indicating the Emitter Pin ? All my Ge's leads... the 3 leads form an > where they come out of the body [looking from the bottom you can see] that 'arrow' points toward the output.

[analog kid]

Alright , The pinout of the transistors has been verified , everytime I 've used different ones., The resistor values have all been rechecked(*including the ones I've replaced now), I have checked the transistor sockets a dozen times for shorts between them, and I'm over 80% sure that the layout is correct and all connectoins are good , God knows I"ve been over it enough<(And the thing's working SOUNDS PRETTY GREAT, but just has this bit of a bias/voltage problem) Anyway Pete I'm not trying to be cross , I know you're just trying to get me to reboot and look at this fresh in case I've overlooked something simple BUT
I do think that we've narrowed it down to a problem IN BETWEEN the Q2 and Q3 transistors, and all that affects their biasing.  So as far as taking it Part by Part , If you could go through everything STARTING there with me (including whatever off board pots,etc.. that come in/out at that point, I think the problem will be there.
 
RG  , If you think from what I've said happened in the circuit SINCE trying what you said , dropping the Resistor to 15k , That the ONLY problem here is still only to do with NOT having low enough leakage in the transistors  in the Q2 andQ3 positions .. PLEASE POST AND LET ME KNOW THAT for sure so I don't waste any time  tearing a correct circuit apart and back together when I SHOULD be looking for and measuring a better  set of transistors!!!]
       Let me know what you think guys. I know this thread just keeps ON

[petemoore]

So...it's gating ?
 These TB things are just plain finicky...it doesn't sound like you're able to get a bias on it. They're anything BUT wire it up 'n go...I'm still trying, after what 2 years to get one that ALways works perfect...the one I have's a mindblower...just acted funny today again for some reason...drifts?...the other ones I had were just as good sounding but worse that way too. I tried one, on a really cold night and got G*LATCHZ z...z, just a splatted gate noise.
 I'm sure it's 'right', just sounds like it's not right enough...and I've found problems in boards I re-checked as right-o many, many times.
 On super problematic first time builds, I've re-built another as a 'second opinion' board, EA tremolo for example, I built two of one version, and one of the other version, 3rd time was a charm, and I figured out what was up on the first one also...say where IS that 'other ea trem...now that I'm thinking about that...hmmm...it was in a ____ type box ....lol. Hafta think 'bout that.

[analog kid]

NO , IT doesn't have that "Gate" problem ever since I straightened out the Q3 C pot NOT trimming. I can only hear the  EVER SO slightest of an uneven decay as certain notes as they fade out IF I put my ear close to the speak and listen! BUT no it sounds good. It's just a question of the voltages not saying what they should say, the battery seems to be draining far to quickly, and there's alot of backgound hum at that last bit , the really wicked end of the gain pot. ( which I have at 1.5k , how important is the 1k on this crkt>?? I know a fuzzface sounds pretty good with a 1 or 2k)
check your PM's Pete.
And yet another update on the voltages!!
Q3 C 4.5
    B 2.27
    E 2.09
Q2 C 2.27
    B  68mV (>?)
    E   0
Q3 C  9.53v
    B  75mv
    E    0
RG !!!! where are you? Please tell me how these look so I can start playing this thing
.