Green Ringer build problems! Voltages and description included.

[newbie builder]

How hard is it to do? I just built a green ringer but I ran out of transistor sockets....so instead I soldered them straight into trying to be very carefull. However, I think I fried one. When I hit a chord, there is a light sputtery sound but nothing else. I checked over all the circuit/wiring and I'm 99% sure it's correct, but if it's really hard to fry a 2n3904 than I'll spend more time checking. Just can't believe how easy it must've been to fry those things- I was really careful when I put em in.

[R.G.]

Modern silicon, like the 2N3904, is pretty hard to fry. They're rated at something like 300C for three seconds.

Do the "measure the voltages" thing. That will probably point to your error.

[newbie builder]

Will do- thanks for the tip R.G.

BTW Just saw somebody post that the Visual Sound amp you helped design is coming out soon- congrads!

[sir_modulus]

If you want a quick fix, just pull the resistor out (desoldering braid is really useful for transistors), and solder a new one in. In future though, consider using a heatsink of some sort (a good DIY one is to just take on end of a alligator clip jumper cable, and flatten it in a vise so it's nice and thin).

Cheers,

Nish

[newbie builder]

I did that to one or two of them and it still doesn't work. I'm about to go out and check the voltages- I built it on perf so no doubt I made some stupid mistake that I didn't notice when I checked over my work..

[oldrocker]

I did fry some 3904's once while building a Pulsar trem.  I left power on with the battery hooked in while soldering and POOF!!  Wasted 2 or 3 tranny's.  The sick part is they were socketed and I forgot to pull them out.  That's the only time that has happened though.

[newbie builder]

Just measured voltages and checked over wiring/perfing for the 4th time and no luck. I also replaced all the transistors with fresh ones just in case. Green ringer, layout used was from generalguitargadgets.com but adapted for perf: http://www.generalguitargadgets.com/diagrams/gringer_lo2.gif

Voltages:
Q1:
E 1.5v
B 1.9V
C 8.4V

Q2:
C .003V
B 8.4V
E 8.8V

Q3:
C 8.8V
E 3.5V
B 4.1V

First project I've ever really been stumped....I can't figure out what's wrong! I had moments like this but after the 4th time of checking over work I usually get it.... O well, I know i'll get it eventually. If i hit a single note, I don't hear anything. If i hit a chord though, i get some sound--like the chord but on a VERY dead battery (and it isn't the battery's fault..I tested it). All sputtery and dying sounding. The only thing that seeems odd is .003 for Q2 C...it seems a bit low. I checked all the components attached to it though and everything is right as far as I can tell....any suggestions?

[newbie builder]

Bump. Any suggestions?

[oldrocker]

I know this is most likely a silly question but are you positively sure the trannys are oriented correctly.  I was so positive mine were in right that I wrote here to tell everyone the schem was wrong on GGG.  It wasn't wrong of coarse and the next morning I looked at it again and sure enough I had them in backwards.  Boy did I feel dumb.  I had to write to say I screwed up.

[R.G.]

Voltages:
Q1:
E 1.5v
B 1.9V
C 8.4V

The input voltage divider, 560K/160K, should produce a voltage of 2.0V on the base of Q1. 1.9V is pretty close. The emitter is at 1.5V, so there is 1.5V/6200 = 242uA of current going through the emitter. The collector resistor, 18K, ought to be pulled down from the 8.8V battery voltage by a corresponding amount. So if you have 242uA in 18K, you get 4.36V. The base of Q2 ought to be sitting at 8.8V-4.36V = 4.44V. Ideally, we'd like this point to be about 2.5V down from the 8.8V battery, about 6.1V. But it's not.

Q2:
C .003V
B 8.4V
E 8.8V

And here we have more strangeness. "Perfect" for this device would be collector at about 2.5V, emitter at about 6.6V. But we have the emitter up at the full 8.8V, and the collector at 0.003V. At a guess, the emitter may be shorted to the +8.8V supply. That would account for some of the oddity in Q1 as well. Look for a soldering problem, either a thread or a loose solder ball.

Q3:
C 8.8V
E 3.5V
B 4.1V

Can't tell much about this one until Q2 gets fixed.

[newbie builder]

Thanks R.G. and Oldrocker. I may have found some transistor sockets, in which case I'll be able to reverse them to double check that I have them in the right way. Wouldn't be the first time I screwed that up! I'll get back soon with how it goes.

[newbie builder]

No more good news- checked over everything again and it still isn't working. Nothing is shorting.....is it possible that reversing Q2  could have done this? I checked the pinnout online and I'm sure I have it right, but if having a transistor in wrong could resolt in that farty sound when I hit a chord then I'll flip it. The only reason I ask instead of just doing it is that I'm running low on those transistors and desoldering will fry it so I'd have to use yet another one. Thanks for the help--

[newbie builder]

Just went through and reversed the trannies one by one.....now i have a soft clean sound. No modulation, not unity...just a soft clean sound......

[oldrocker]

Then I would say the trannys were right before you changed them then.  Although nothing was brought up about the PNP tranny in the middle (Q2)  the emitter faces the opposite of Q1 & Q3.  Other than that I would take R.G.s advice and go over those solder joints.  He knows his stuff.

[newbie builder]

Yeah he sure does. Always scares me when he comes up with an amazing scientific reason for all things electronic in a matter of minutes. I've been over all the perf wiring 4 times, and 2 of those times I used a magnifying glass to check every joint......I'm really at a loss. No doubt It's probably a very stupid and basic mistake but I can't figure it out. I just got some vero, so I might just desolder everything and move it onto vero- after building a booster on vero I now see why so many people use it. It's much easier......MUCH...easier...Thanks for the help-

[petemoore]

  Daft, I just set 'em aside until I'm feeling really dogmatic one day.
  I'll put the DMM to it every which way, testing for actual continuity from resistor lead to tranny socket, [and non-continuity to Everywhere else it isnt supposed to be connected], test every resistance of every resistor on the board...this one may cause 'anomolous' readings because an alternate current path may exist through the circuit...
  Try to apply what RG wrote to focus debugging where it's most likely needed.

[newbie builder]

I gave up on perf...I desoldered the entire thing and am ALMOST done putting it on vero. Man vero is wayyyy easier- took me less time to desolder from perf and put it on vero than it did to perf in the first place!

[rockhorst]

Using this thread for a lil question about the green ringer I will start building pretty soon: is it ok to just throw in the FETs with resistances as in the schematic, or is there any use in biasing them individually?

[3/4 North]

I tried that, just used whatever I pulled out of the bag.  I don't think it's so much an issue of biasing the transistors but of mactching the resistors and diodes.  Mine sounded much better when I went back and did that.  And also I used the US made PNP germanium transistor from small bear (it had a very low hfe).

[petemoore]

is it ok to just throw in the FETs with resistances as in the schematic,
  ok? it will not work like with BJT's if at all.
  Jfets GR? probably not without 'some' redesign, if then.
  I know there must be reasons for it, but I can't expound more than that.
  If you socketted, you Could* try subbing gate for base, source for E, and Drain for collector...and diddling aroud with biases.
  I don't think the Jfets would work with the FWR because of voltage requirments...sketchy, best I can do.