PHASE 90 PROBLEM

[grani79]

Hello!

I built an Mxr phase 90 clone. When i switch my circuit on I hear only my normal guitar signal... No Phase! Why?? the scheme is from tonepad

[petemoore]

I built one that did the same thing ie..no phaze.
 I used a DMM and a 'finger probe' [finger connected to a conductive wire or screwdriver].
 I use the DMM to verify all connections that 'should be' are made, and all that 'shouldn't be' arent made. Also I check for Gnd and PS at each chip. There are numerous other ways to apply the DMM.
 I poke around [beginning at the output 'end' and following as far toward the center of the ckt as I can and still hear the source [finger buzz] at the ouptut.
 I use a 'similar' but opposite method from the input...a monitoring amp [grounded to the ckt and source], with it's 'hot' [tip] connection on an insulated wire or probe...audio probe.  follow the source signal as far as you can from the input till you lose it...where you lose it, look for problems there.
  I did a SS phaze on a PCB Fransisco made [great work Fransisco!!] and had to reheat where six leads, a large copper pad to accomodate the leads needed to be retouched...I heated ALL the metals at one time at two points of the pad...using a longer interval of soldering iron tip contact...I had done them individually, but that allowed a cold solder there...with the increased thermal mass it takes more heat application for the solder and leads to work right.
 Maybe take some IC pin voltage readings and post them...this may help to reduce the thousands of problematic possibilities.

[smoguzbenjamin]

Definately. There's probably not even just one mistake there, probably many, which is something you gotta get used to. If there are any trimmers to set, make sure they're set right, that could be a problem.

[grani79]

I USED TONE PAD SCHEME 2nd version layout:
http://www.tonepad.com/getFileInfo.asp?id=42

with all the components indicated and 5,1V zener

Ok these are the voltage:

IC 2: 8,75 4 4 4 4 4 4 0
IC 3: 8,75 4 4 4 4 4 4 0
IC 1: difficult to mesaure... it's oscillating! 8,75 4,5 4,5 4,10 4,5 4,5 2,70 0

Q2 Q3 Q4  Q4
DRAIN: 4
SOURCE: 4,5
GATE: 4

Q1:

E 2,22
B 3,44
C 4

DIODE D2 VOLTATGE:0 and 4,4

[Aharon]

Did you get 4 matched JFets?....... or it won't  phase.
Check GEO on how to match them or install sockets and try diferent ones until it does.
Aharon