Tonepad Phase 90 Problem

Started by fair.child, March 26, 2012, 02:39:45 PM

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fair.child

Recently, I've got a phase 90 built from tonepad-pez90. Unfortunately, it didn't work. I wasn't able  to hear anything from my built, so I tried several debugging with audio probe. I changed 5n value to 4n7 and 15uF to 22uF electrolytic cap. I look for bad solder joint, but I didn't find  it, and tried to triple check my pedal. right now I pretty stuck and don't know how does the exact value of tht transistor and IC pins.

I've been tried to get it working, but it won't until today, so I need help. Here are some information about my TL072 and transistor pins. I used matched 2n5952 on 1.901V.
and I don't have 250k trim on hand so I changed it into 200k trim

IC1 TL072
1-5.22v
2-5.23v
3-5.21v
4- -0.001v
5-4.22v
6-4.47v-5.9v
7-8.41v
8-9.04v

IC2 TL072
1-5.22v
2-5.22v
3-5.21v
4-0v
5-5..23v
6-5.23v
7-5.22v
8-9.04v

IC3 TL072
1-5.23v
2-5.59v
3-5.22v
4-0v
5-5.23v
6-5.45v
7-5.23v
8-9.05v

2n4125
E-2.75v-3.00v
B-5.23v
C-5.22v

2n5952
Q2
G-2.703-2.979v
S-5..23v
D-5.22v

Q3
G-2.703-2.979v
S-5.22v
D-5.23v

Q4
G-2.704v-2.98v
S-5.22v
D-5.23v

Q5
G-5.23v
S-4.56v
D-4.55v

Zener- 5.23 V

I really need any suggestion and information about this pedal. I'm curious about my phase 90 problem, I've also tried to change IC1,2,and  3 to a new TL072 but it still didn't change the result. I've got nothing on my amps. So please help me to figure it out.

Cheers all

Govmnt_Lacky

A few suggestions:

1) Ensure that your FETs (5952s) are properly oriented (turned the right way)
2) The change from 15uF to 22uF is pretty steep (usually want to go +/- 10%) You may want to try 10uF instead. Not within 10% but closer than 22uF  ;D
3) Post some pics of your build.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

fair.child

Quote from: Govmnt_Lacky on March 26, 2012, 02:49:53 PM
A few suggestions:

1) Ensure that your FETs (5952s) are properly oriented (turned the right way)
2) The change from 15uF to 22uF is pretty steep (usually want to go +/- 10%) You may want to try 10uF instead. Not within 10% but closer than 22uF  ;D
3) Post some pics of your build.

Hey mate,

thank you for your quick suggestion and here some quick pictures of my board. I rolled on my board by myself. I've read about other issue about this problem and some of them said that I should change the 200k trim, should I do it ?


IMG_0572 by DIY Parts + PCB Center, on Flickr


IMG_0574 by DIY Parts + PCB Center, on Flickr

Govmnt_Lacky

1) Check that your Output wiring at the PCB. It looks like it may be shorted to ground.

2) Check that your Rate pot Lugs 1 & 2 (shorted together via the PCB) are NOT shorted to Lug 3. It looks like it might be in your pics.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

fair.child

#4
Quote from: Govmnt_Lacky on March 26, 2012, 03:27:07 PM
1) Check that your Output wiring at the PCB. It looks like it may be shorted to ground.

2) Check that your Rate pot Lugs 1 & 2 (shorted together via the PCB) are NOT shorted to Lug 3. It looks like it might be in your pics.


nothing shorted between output and ground and lugs 3 are not to lugs 1&2, so any other suggestion ?

Thank you for your concern

Cheers all

Govmnt_Lacky

Double and triple check ALL resistor color codes.

Might have to move up to the 250K trimmer.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

fair.child

Quote from: Govmnt_Lacky on March 26, 2012, 03:47:30 PM
Double and triple check ALL resistor color codes.

Might have to move up to the 250K trimmer.

Here some guts of our discussion, I moved up 22uF and change to 10uF , as your suggestion to lower 22uF cap to 10uF, and check again about 500kC lugs, and output lugs


IMG_0579 by DIY Parts + PCB Center, on Flickr


IMG_0578 by DIY Parts + PCB Center, on Flickr


IMG_0577 by DIY Parts + PCB Center, on Flickr


IMG_0576 by DIY Parts + PCB Center, on Flickr

About move up to 250k, in my town, the don't have 250k trim, they just have 200k trim. That's all for the largest value of trimmer, so what should I supposed to do ? I think about change it to Bourns 200k trimme.

fair.child

Hey mate,

Seems the problem has been solved here, I've got now my phaser working, it PHASING finally, yeayyyy  :icon_razz:  :icon_razz:  :icon_razz:
but I'll think to give more depth on it, could you please tell me how to do it ? like in MXR Phase 90 evh series.

I decided to used new 200k trim, and it's working, I turn left a bit and it comes the phaser sound,

Thank you all

Cheers

ChanchoPancho

I don't know if it gives you more depth, but when I built it, i like it more without the the feedback R (22k).
The depth can be controlled by the trimmer. Try turning it with a fast rate position, it's easier this way.