Help with an npn tone bender turret layout

Started by Gumby212, December 11, 2018, 06:47:46 PM

Previous topic - Next topic

Gumby212




Can anyone help me figure out why this doesnt work? Its my first attempt at a turret layout. I made the design myself  and im fairly confident the design is correct. Im afraid i maybe damaged the germanium transistors i got from smallbear (i did not test these before installation but usually trust smalbear). I seemed to need more heat soldering to the turrets, and im thinking maybe i put too much heat on one of them, or all of them... is this a common issue? Removing the transistors would be such a pain considering how i wrapped them around the turrets before soldering. Guess that wasnt very wise? The testing ive done with a meter (i have limited knowledge with doing this) just confuses me more. First off, when testing voltage, i get 9v on the 9v side of the 10k resistor from the collector of the first transistor, but nothing on the collector side. I changed resistor with same result... how can this be? When using an audio probe, i get sound through the first 4.7uf cap (from first lug of footswitch to base of first transistor), but no sound at the collector or beyond. Does this mean that transistor is bad? Its weird that when testing continuity with a multimeter, i get nothing through that first 4.7uf cap... the meter seems to work so im confused. I did originally have that cap backwards, but swapped it with a new one in the correct position with same result. This took me all day and i was pretty proud of the design. I know daisy chainning ground and 9v isnt advised, but i couldnt really see anyway around it, and have never had issues doing it in other builds. You can see that i took 9v to turret #2 and jumped it to turret #6 on the top strip. I took ground to turret #1 and jumped it to turret #3, then to turret #2 of the bottom strip. The last filter cap is a polyesterene? type and i was under the impression its not polarized so i didnt pay much attention to its orientation, even tho it seems to still have a neg side (that may be the wrong orientation if it is polarized and i have not swapped it out yet). From left to right, all of the transistors are EBC and they are npn germaniums. Any help would be much appreciated.

bluebunny

#1
Sorry to say this, but those joints don't look like they got hot enough.  It takes a lot more effort to heat up a turret than a wafer-thin spot of copper track.  And all this heat may not be good for Ge transistors or polystyrene caps.  Did you use a heatsink when soldering these?

I did a couple of tagboard builds recently, and whilst they visually looked OK, I had quite unexpected discontinuities and had to redo a number of joints.  Have you checked for continuity between turrets (and between component leads) which you believe should be connected?
  • SUPPORTER
Ohm's Law - much like Coles Law, but with less cabbage...

antonis

+1 to what Marc said..

All turrets for use have to be "on air" soldered (no component), maybe using a thiker solder tip, previously to items populating..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Gumby212

I was surprised by how much heat it took. Im surprised i need more but considering my continuity testing is failing all over the place im assuming thats my issue. Was i supposed to heat shrink the transistor leads? I figured that was just to protect long leads from touching other components, not necessarily for heat purposes. Since my transistor leads were so short i did not use heat shrink. Does heat shrink help protect the transistors? I did use an alligator clip on the head of the transistor to try and absorb some of the heat. I went on and removed the transistors to test out of circuit so i will be reassembling soon and when i do ill be sure to use more heat and take my time. What do you mean by "on air" soldering? I appreciate your alls input on this. Thank you so much

Tony Forestiere

Heat sink. Like an alligator clip on the transistor lead to keep the component from over-heating.
"Duct tape is like the Force. It has a light side and a dark side, and it holds the universe together." Carl Zwanzig
"Whoso neglects learning in his youth, loses the past and is dead for the future." Euripides
"Friends don't let friends use Windows." Me

thermionix

Quotei get 9v on the 9v side of the 10k resistor from the collector of the first transistor, but nothing on the collector side. I changed resistor with same result... how can this be?

That suggests to me that the lower left transistor is shorted C-E.

Gumby212

Oh i see. Heat sink, not heat shrink. I did use a heat sink. Im hoping my issue was bad solder joints bc i am getting odd results wh ed n testing continuity. Thanks for the help guys!