Green Ringer Debug (It won't RING).

[Sir_Ian]

1.What does it do, not do, and sound like? Ok...this is the weirdest debug ever. I finished it thanksgiving morning. And it didn't work. I was hoping it would, but nothing else I've ever built started up on the first try...so I wasn't surprised. So I set it down because the rest of the day is for the family and I just decided to fix it later. What happened when I first plugged it in was that I got sound, but no modulation or octave up. Just a slight drop in volume. (and no...I didn't have it in bypass, when its bypassed, there is no volume drop.)

Friday (the next day) I came back with some ideas of what might be wrong. Decided to plug it in to get listen to it one more time to see if it sparks some ideas, and I was blown away. THE THING WORKED. I had octave up, When I played chords it souned weird and beautiful. I knew that what was wrong wouldn't last, and sure enough when My brother walked in and stomped on the switch it went back to boring old volume drop. I opened it up and I saw that one of my solder points was close to a metal standoff and I thought that it might have been touching and messing with the effect. I scraped the wire up some. with a pick, and it was fixed again. HOORAY.

But I was afraid that the wire might still touch it over time. So I decided to permanently fix it by resoldering the wire in one pad over. (I'm using perfboard). Plug it in, and it is back to volume drop. This makes me think....I was probably chasing after the wrong thing and it was coincidence that it was working when it was. The problem is randomly intermittant which would often times mean a loose wire. But I know my wires must be fine or else I wouldn't be getting sound to and from the board. So maybe its a cold solder joint. So I then proceed to reheat all my connectiong and make sure they are good. It still doesn't work. I bounced some ideas off a friend at work...he says it could be a bad capacitor. He says that he had a cap go out on him, it left physical damage to the board. I see no physical damage or little brown spots. So now I turn to you. I've gone as far as I can go without just replacing every fricking component. I should tell you that I'm using an unverified layout that I made using the DIY layout creator. I'll post it below so you can look at it. However...I dont' think its a layout flaw because I checked it 5 times, and if it was a layout flaw the effect wouldn't have ever worked. Mine worked some of the time. I also have voltages posted below. Thanks for the help.

2.Name of the circuit = Green Ringer

3.Source of the circuit (URL of schematic or project) = http://www.generalguitargadgets.com/pdf/ggg_gro_sc.pdf

4.Any modifications to the circuit? Yes. I have input cap switching. I switch between the standard .047uf and a 1uf cap. How I have it rigged can be seen in the picture below.

5.Any parts substitutions? R1 is supposed to be a 560K. I only had 510Ks. I measured through mine till I found one that was off by quite a bit. The resistor I used measured in a 540K. (This is the nice thing about buying the cheaper resistors with the 5% tolerance instead of the 2% tolerance.)

6.Positive ground to negative ground conversion? No

Battery = 8.8volt

Q1
C = 2.6
B = 1.72
E = 1.33

Q2
C = 3.28
B = 2.6
E = 3.3

Q3
C = 8.8
B = 4.42
E = 3.61

Comparing to some ideal voltages here...   http://www.generalguitargadgets.com/pdf/ggg_gro_instruct.pdf
it looks like something is up with Q2, but I don't know what. I checked the pinout several times...with an online datasheet and with the hfe function of my multimeter.

and lastly here is the layout i made and used.


By oot1979 at 2008-11-29

[R.G.]

I believe that your problem is with Q1 collector being too low. Some possible scenarios are:
- R3 is the wrong value
- R3 is open
- Q2 is shorted collector to emitter or collector to base, possibly by solder

Check those out.

[Sir_Ian]

R.G.

You were right. THANK YOU. There was a cold solder joint which basically made R3 not connected. Fixed it, and wallah, it rings. Thanks for looking in and offering your expert opinion. Much Thanks.

[R.G.]

My pleasure. I've found that if I guess often enough, some of them are right... 

Happy ringing!

[forestcaver]

Hi, sorry to jump in on this thread, but I am having problems as well. I built one months ago, pulled it apart and rebuilt it a couple of times checking the components. The only differences I have made from the schematic is to use 1n4148 diodes instead of 1n914. Can that make a difference ? (I thought they were electrically very very similar).
Using 2n5088s and a 2n3906

My voltages are:

9v battery: 8.8v

Q1
C  7.22
B  1.12
E  0.58

Q2
C  0.95
B  7.22
E  7.90

Q3
C  8.85
B  3.89
E  3.55

I get a horrible nasty fuzz sound (not in a god way) - with no ringing at all...
I would be really grateful for any help - I am really stuck (I have read the debugging thread and searched for greenringer threads !)

Cheers,
Andy

[Zben3129]

Q1's B and E seem a little low, but they are .6v apart so the problem is probably not there.

Q2's voltages are off...Collector should be somewhere around 2.5-3v. Check for problems in that area. Also base and emitter are high but that could be because of the problem at Collector

Q3 looks fine to me.


Zach

[Sir_Ian]

hey forestcaver....Don't GIVE UP.

I came pretty close to it but I'm glad I didn't. This pedal creates a great sound...it'll be worth it when it works.

My first suggestion would be to do what RG suggested to me. Make sure you have the right value resistors, and they are connected. (my problem was one cold solder joint. Fixed it...and all was well in the world.)

For me my Q1 collector was too low..because of the cold solder joint. Yours is about 2 volts too high. So definately check R1, R2, R3, and R4. Your Q2 voltages are all wrong. Do you have it orientated correctly?

if you check these things....something I suggest because it has worked for me is to take the schematic and start checking connections. Highlight all the connections you've made. If something is not highlighted when your done...you know you have a missing connection. It takes a while, but probably won't take too long with a small circuit like this.

One last thing. I remeasured my voltages after i had it fixed and working and they came pretty darn close to the general guitar gadget's set of voltages that I linked to. When your done. Yours will likely be very similar too. Good luck, and don't give up.

[forestcaver]

Thanks for the suggestions.
I couldnt see anything wrong (after checking all the resistors). This was built on a home-etched pcb based on the ggg one. I was so frustrated I built a stripboard layout yesterday and all the voltages were pretty much identical to the pcb one !!! I wonder if there is a problem with the transistors (I bought them all at the same time) - I'll pick up a few more 2n3906 and 2n5088 s when I can. Hmm....
Anything else I am missing ? I am pretty sure that B C E are orientated correctly.

Cheers,
Andy

[Zben3129]

Holding the transistor upright with the flat side facing you would probably be "E B C"...Also are you soldering them or socketing them?


Zach

[forestcaver]

Soldering...
(I was too confident - I've built Fuzz faces, a phaser, a tube screamer and a valve amp with only minor problems; on such a small build I wasn't anticipating too many problems - oops !!!).

Cheers,
Andy

[Zben3129]

I started by socketing everything burnable for the first few builds, and since then I have been soldering all BJT transistors and some FETs (always socket IC's and MOSFETs still), and have only ever burned one. Got through about 8 builds without torching one, and then out of the blue I killed one. I got a sound that was kind of like a white noise, waterfall sound. May be something to consider if you cannot find anything else wrong after checking a bunch.


Zach

[forestcaver]

Thanks for everyone's help - it was a duff Q1. I had two 2n5088s from one source and some others from another source.
I randomly had put the two "duff" ones in Q1 in both builds - so the error was the sameeach time. Anyway, got it working now ! Bizarre...

Thanks again,

Andy