Mongoose Fuzz; any schems?

[Bernardduur]

Hi all.

I've got a burnt down Mongoose fuzz for free; one problem: it is completely burnt down (black, black, black). There are some good resistors and caps, but most is gone.

Anyone has some kind of schematic so I can try and fix it........ I want to keep it in original state........

[cd]

LOL unlucky for you, the search is not working.  That pedal was dissected like a frog in biology class.

Anyway, it's your lucky day:



In the future, when it's back up, the search function will be your best friend.

[Bernardduur]

Thanks man! You saved me!

And yes, I've tried the search. Lukily the site is up again; did not know what to do without this..........





addiction?

[Bernardduur]

Anyone tried the schem? I only get this kind of sputter fuzz that does not react to the fuzz knob

And yes, I checked it all more than once.

[Steben]

Anyone tried the schem? I only get this kind of sputter fuzz that does not react to the fuzz knob

And yes, I checked it all more than once.

Collector on Q1 should be very close to 4,5V I guess to prevent gating on the IC. I guess you DID connect pins 7 and 4 on the Opamp?

[Bernardduur]

Yes, I connected pins 4 and 7 (and the right way BTW). Voltage on the collector of Q1 is far from 4.5V (0.24V). Voltage between R4 and R5 = 4.5V

[Steben]

Yes, I connected pins 4 and 7 (and the right way BTW). Voltage on the collector of Q1 is far from 4.5V (0.24V). Voltage between R4 and R5 = 4.5V

Aha!!! Try to connect that in-between point to the + input and C4 then. ;-)
It should work.

[Bernardduur]

OK. Now I am getting some Fuzz; only when the volume knob is fully open and the fuzz knob is at 9/10th of it's turn.

[Steben]

OK. Now I am getting some Fuzz; only when the volume knob is fully open and the fuzz knob is at 9/10th of it's turn.

Actually I checked all available schematic stuff and the input of the Opamp should be indeed connected to the collector... :roll:
It should make for more gain off course, but the biasing voltage of the opamp is odd. 0.24V is way too low.

[Doug_H]

There is a mistake in the schematic posted earlier in this thread. The 2M2 resistor should be connected between the base and collector of Q1. It provides negative feedback for the stage. This will put the collector voltage at around 3.5v, perfectly acceptable (according to my sim). According to the sim, this sucker should really blast...

Doug

[Bernardduur]

That was it!!! Thanks all.

I made a new schematic; it can be found here: http://www.student.kun.nl/r.kerkhof/Mongoose.jpg

[Steben]

There is a mistake in the schematic posted earlier in this thread. The 2M2 resistor should be connected between the base and collector of Q1. It provides negative feedback for the stage. This will put the collector voltage at around 3.5v, perfectly acceptable (according to my sim). According to the sim, this sucker should really blast...

Doug

This suggests Marty's layout is incorrect then?

[Bernardduur]

It is 99% correct. Check my new schem above

[puretube]

so: you are anubiX??

I`m GONE !!!

[Bernardduur]

Me? I just changed the schem

[puretube]

Never trust a schematic on the web - NEVER!

[MartyMart]

That's interesting as it was drawn out from original photo's of mine !!
And the version that I built is working a treat !! ??
I will however "dive in" and make that 2M2 a feedback resistor across
Q1, I'll let you'all know what happens ..... !

Marty.

[puretube]

I do trust photos, though (when un-edited)...

[Doug_H]

Try it and see, Marty. I haven't actually tried it. It just didn't look right and didn't work without the mod in the circuit sim.

Doug

[Bernardduur]

"and my clone just gave me hard times getting some tones out of it"