Phase 90 picking up radio signals

[Milotic]

Hey guys  nearly finished my 3rd build, a MXR phase 90 with script/block switch.  I got the schematics from http://www.sabrodesign.com/wp-content/uploads/2010/08/MXR-Phase-90.gif
Followed most things accordingly, changed C9 with a 22uF instead of a 15uF.
Main issues;
picks up radio signals, like i can listen to a talk show on my amp
makes phase like high pitched oscillations
bypass signal doesnt work, i followed the 3pdt true bypass from generalguitar gadgets.

I had a battery lying around, it measured about 8.0-8.1volts.  So i did a probing of the diodes, ics and transistors.

IC1 (tl072)   IC2 (TL072)  IC3(TL072)
1=3.8         1=5.5          1=5.1
2= 4.1        2=4.1          2=4.7
3 = 4.1       3=4.1          3= 4.1
4 = 0          4=0            4=0
5 = 4.0       5=4.2         5=4.1
6 = 3.9       6=2.6         6=4.8
7 = 3.1       7=4.6         7=5.54
8 = 6.5       8=5.9         8=6.5

D1 (1N914)  D2 (5.1 Zener)
A=0             A = 0
K=6.4          K=3.96

Q1-Q4 (2N5952) all the same.   Q5 (2N4125)
D=4                                          E=0
S=4                                          B=3.6
G=2.1                                       C = 1

Battery voltage died abit after the measurements and it gives a reading of 7.15v

any help would be appreciated greatly.

[Milotic]

bump?

[amptramp]

The bypass switching is pretty simple, so if it doesn't work, check your wiring.

Most stages are linear so pins 2 and 6 should be driven within a few millivolts of pins 3 and 5 respectively although IC1b is operated as a comparator oscillator, so it may not (but according to you, it does).  Are you using the tonepad IC pin assignments?  In most other cases, they match and they all should.

The input goes to a 10K resistor then a 0.01 uF capacitor.  Frome the junction of these devices, put a 100 pF capacitor to ground ( you might be able to get away with a 47 pF).  This will stop any radio signals on the input.

Your 9V battery voltage should show up on pin 8.  If it is as low as it is shown, you will have trouble.  You depend on keeping D2 biased above its zener voltage of 5.1, but the zener is essentially out of the circuit with battery voltages this low.  Perhaps you should try a wall wart and take the measurements again, then see if it behaves.

[Milotic]

i connected this to a 9v power supply, which gives 9.55v constantly. 

New values are

IC1 (TL072)
1= 1.47
2= 5.1
3=3.98
4=0
5=3.98
6=3.98
7=6.48
8=9.55

IC2 (TL072)
1=1.56
2=4.01
3=3.98
4=0
5=3.98
6=3.98
7=6.40
8=9.55

IC3 (TL072)
1=8.78
2=1.33
3=2.71
4=0
5=3.50
6=4.34
7=4.34
8=9.55

Q1-Q4 (2N5952)
D=3.98
S=3.98
G=1.42

Q5 (2N4125)
E=3.90
B=5.26
G=1.42

D1 (!N194a)
A=9.55
K=0

D2 (5V1 Zener)
A=3.98
K=0

My suspicion is bad grounding.  Since i got lazy and connected all the ground wires to the ground on the 3pdt switch.  Ill disprove/prove this after the final exams.
I wasn't using a pot in the test, since i do not have one atm.  All i did was joined those wires together.
Btw if i wanted to make a 500k anti log pot replacement, do i just wire a 1M resistor on lugs 1 and 3 on a 1M Linear pot?


help would be appreciated.

[radio]

Wouldn't be that unusual if it s not yet boxed.

Besides having only one ground point is a good policy,

still needs better to be connected to it s metal enclosure.

Greets JM

[tasos]

sit back and enjoy the talk show...! no just kidding....do you get guitar sound on your amp?

[Milotic]

no sounds of any kind.  i followed the guide from general guitar gadgets, for the 3pdt true bypass, w/ battery and dc.

[tasos]

well try to see if this works without using bypass 3pdt ... etc....just use input jacks and battery....
i didn't understand...when you play on your guitar...do you get YOUR guitar sound?

[Milotic]

no guitar sounds at all. 

[radio]

Hi

Funny , I just posted the same link to a German forum.

This is how it works to get radio by guitar >P90>Amp

http://en.wikipedia.org/wiki/Detector_(radio)

However I m unable to tell you which components are involved

concretely in your special build!

Regards JM

[tasos]

if you used different parts from what you were ased for...see if polarities of the two parts match...
also...a check of your polarity in electrolytic capacitors wouldn't take more than a minute!

[Milotic]

All the capacitors are the right way around.  I think i might just start again.

[tasos]

ok...that's a view....try check all polarities...also check if all parts are supplied with power...with a dmm[for sure!]ok so that's it...check again all polarized parts..see ya!

[Milotic]

thanks for the help tasos.  imma go over it piece by peice and check with a scheamtic.

[tasos]

that's the best thing you can do! if you don't find out what's wrong...then it is a good idea to use that simple cable construction!it really helped me!
http://www.diystompboxes.com/pedals/debug.html [in case you don't know it! ]