Phuncgnosis Problem, Help!!

[tatems]

I built Tim Escobedo's Phuncgnosis using Cab 42's layout but when i fired it up i got a really badly distorted sound.

The wah is present though. The distortion more present on the up setting than on the down setting of the wah. I'm using red 3mm leds. Could those be the problem? I've replaced all the diodes, the IC and the 1m pot to see if they were the problem but it is still the same. I even switched between a Tl062 and Tl072 to see if there was any diffrence but there wasn't.

I've got a clip here of my problem with me hitting some random notes (me playing very badly). I changed the switch from down to up halfway through,  you'll hear the switch pop.

http://www.msnusers.com/Stompaholics/documents.msnw?fc_p=%2FSound%20Files&fc_a=0

Also i reused components from my first attempt with my layout so i might of overheated something but i don't think so. Also i'm getting my new DMM tommorow so i can't give you any readings yet.

Cheers
Tatems

[cab42]

Tatems,

I haven't build it myself yet, so the layout is still not verified.

I have had all the parts ready for more than a month, but you know, job, family etc...

Which one did you build? onboard or off-board version? I will check the layouts again and see if I can find any errors.

Regards

Carsten

[tatems]

Which one did you build? onboard or off-board version? I will check the layouts again and see if I can find any errors.

I built the on board version.

Thanks
Tatems

[cab42]

Tatems,

I just checked the layout (with offboard LED's).

I found one error, the 47K resistor (the framed one) should go to ground, not to Vref. You can place it so it run from row 6 (counted from top) to
either row 1 or row 10, both rows are ground .

I don't know if this will solve you problem, but at least it's a start.

I will update the layouts as soon as possible and hope I will be able to build this weekend.

Let me know how you're doing

Sorry for the inconvenience

Carsten

[cab42]

Which one did you build? onboard or off-board version? I will check the layouts again and see if I can find any errors.

I built the on board version.

Thanks
Tatems

Seems as our posts crossed.

The error i found also applies to that version.

I will check it later.

Regards

Carsten

[tatems]

Carsten, thanks for all your help so far but moving the 47k resistor did nothing. I took it out of the circuit completely but the same distortion thing happend. It could be my mistake or i might of burnt out a component, i hope to get it working the weekend though.

Thanks again,
Tatems

[cab42]

I didn't find any additional errors in the onboard version.

However, there is a missing label on D2 (the standing diode) regarding orientation. The cathode should point to row 2 and the anode should point to row 3.

The "out" label on row 9 to the right is also missing.

Regards

Carsten

[tatems]

Still no luck!

After correcting one error i fired it up again and the distortion cleared up a little but there isn't any wah now. :? I replaced the 47k resistor again and it only minimised the pop as it should.

I got some voltage readings of the IC which is a TL072

IC1
P1 3.21
P2 3.52
P3 1.23
P4 0.02
P5 2.48
P6 1.61
P7 3.72
P8 8.03

My battery is 8.03v. I can get the readings of the diodes and led's if needed. Also i noticed before i fixed my error the 3rd led from the +9v of the down setting pulsed in time with my strumming but this stopped when i fixed my error. Also one more thing, are the all the leds meant to light up on the down setting? cause only the 3rd one from the +9v is lighting up dimly and the 2nd very dimly.

Thanks
Tatems

[tatems]

Anyone???

[tatems]

I'll try replace the electrolytic caps and the two 680pf ceramics because they might've been damaged when i desoldered them from the old board. And if that doesn't solve it, well i don't know.

[Naz Nomad]

You guys rock ... I just finished an unsuccesful build ... then I read this thread ... 4 green LED's later and it's working phuncing perfectly ...

Huge man-hug for everyone ... lol

[cab42]

I use my phuncgnosis al the time (i.e. too much).

Mac suggests some mods here:

http://www.diystompboxes.com/smfforum/index.php?topic=49246.0

I have tried the first one with success and I'm also planning to try out the other mods.

Regards

Carsten