Problem with a Rodent Kit from GGG

[incubus20851]

Hello,

I have a problem on a Rodent Kit from General Guitar Gadgets.

I made this kit right and i have normal sound when the pedal is OFF but when i engage the pedal ON, i have to level up my amp very far to hear a little bit of the effect souding. Even when the pot volume is at it's end

What can be the problem ? I have verified 3 times the schematics and all it's OK, i have sound, but very very low volume. I use a new 9V battery.

So if you could give me some tips, it would be very cool.

Thanks a lot for your response

[anchovie]

Please read the "Debugging" thread, follow the instructions and post back with the results.

[incubus20851]

Ok Thanks,

But i can't find info on "low or weak sound in outpout". Do you have info on that ?

Thanks for your response
Cheers from France

[anchovie]

You need to provide the voltages and other information asked for. There is no generic cure for weak sound, the information requested in the Debugging thread will assist with diagnostics.

[incubus20851]

Hello, so here we are :

Here is the checklist to fill out:
1.What does it do, not do, and sound like : It as normal sound when pedal is OFF, when pedal ON there is Effect in the signal but very very low volume even when the Pot is at it's best
2.Name of the circuit = RODENT KIT from General Guitar Gadget
3.Source of the circuit (URL of schematic or project) = http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=92&Itemid=26
4.Any modifications to the circuit? No
5.Any parts substitutions? No
6.Positive ground to negative ground conversion? Positive ground i guess ?
7. I'm not at home and i forgot to do that... But this will be coming !

I assume that the number of the pins are like this below ? :


I take the mesure from one to the clip of the battery and one at the Pin of the IC (When The effect is "ON")
IC1
P1 : Normal : 8.4V  My result : 0,51
P2 : Normal : 4.5V  My result : 4.9
P3 : Normal : 4.1V  My result : 2.46
P4 : Normal : 0V     My result : 9.44
P5 : Normal : 0V     My result : 0
P6 : Normal : 4.5V  My result : 4.94
P7 : Normal : 9V     My result : 0.46
P8 : Normal : 4.6V  My result : 0.51

I see that i have a huge difference at some pins, but i can't figure out why.
Maybe you have a clue ?

Here is some picture of the pedal :






Thanks a lot for your time and response, i appreciate
Best regards !

[anchovie]

From those readings, the power supply to the chip (pins 7 & 4) is reversed.

[incubus20851]

Ok thanks,

And how do i make them in right place ? what is to be replaced ? and where ?

I'm sorry, i'm new in the build of pedal 

Thanks a lot for the response

[Hides-His-Eyes]

have you checked the power supply is the right way round?

[flintstoned]

If that's the case you might have your dc jack wired backwards. Use your continuity setting on your meter and see if those are right (ground to pin 4 and + to pin 7)

[ryanuk]

Looking at the pic and schematic - isnt the 2N5458 also the wrong way round (assuming it was a 2N5458 provided with the kit)?

RyUK


Edit: Yeah, pretty sure its the wrnog oreintation. Drain shold be at 9v. See link.

http://www.rapidonline.com/netalogue/specs/47-3506e.pdf

[incubus20851]

Hello,

At the begining, i had the 2N5458 mounted in the other position and the pedal had produced sound with effect "OFF" but nothing with the effect "ON" so i ordered a new one and i put it as the picture show right now.

If the 2N5458 is backwards, the pedal won't produce any sound ? No ?

The gently guy from GGG told me "The transistor is mounted backwards, but that doesn't account for the messed up voltages on the IC.
"
If the transistor is in backward position, is he dead ?

I'm gonna check the DC jack. Thanks for the advice !

Thanks a lot for your support !!

[ryanuk]

I'm not sure of the impact of mounting the FET backwards, but mostly likely it wont produce any sound. I dont think this should damage the FET, but you never know..

The main problem is the power supply voltage, so flip the FET, then fix the power problem. If it works then you'll know if the FET is ok. (Assuming there are no other wiring issues).

Check to see if you jack is wired just like the one on page 2 of this link...

http://www.tonepad.com/getFile.asp?id=76

As discussed above, there should be 9v at the dc jack to feed the circuit.

If your not confident on how it should be wired then closer pics of the DC jack will be useful.

RyUK

[moose23]

I'd be pretty sure that transistor is the wrong way round. The GGG pcbs were clearly marked on the kits I bought.

[MmmPedals]

A transistor the wrong way around may pass a signal and the result would be exactly as you describe, a weak signal (prob. not distorted).

[incubus20851]

You're totally right i change the position of the transistor and all works fine.

No longer lost of volume. All works great

Thanks to all of you for helping me.