I've just resurrected a classic Morley Phase Shifter - great optical circuit.
While I was able to find a basically readable schematic the circuit has five trimmers in it and I can't find any documentation on either the preferred settings or adjustment procedure.
According to the schematic at Shematic Heaven for the PFV they are:
1 - LFO output adjustment the actual name is unreadable)
2 - Lamp Bias
3 - "Unreadable" Lamp
4 - Mixer (Wet/Dry) in Phaser Circuit
5 - Harmonic trim
Aside from the Lamp Bias, which I set so that the lamp worked measured by the Mk 1 eyeball setting, the others I set centered.
The pedal works and sounds great
But I'm sure that with the correct settings it would sound and work even better.
Anyone know where I could locate, or who might have the settings for the circuit?
Here is a cleaned up but still not very readable schematic and instructions and what appears to be a re-draw of same. I notice there is a capacitor missing at the input transistor collector in the re-draw.
I can't answer the original question though it looks like some of the trimmers set the limits for some of the controls.
This is the documentation I have - but the schematic is clearer for the "official" one.
You'll notice that the Pro-Phaser (#3) is slightly different than the Phaser - Volume (#1)
#1 has the volume circuit lamp (the LDR appears to be missing)
The location in the circuit, and what they are called, of a couple of trimmers is different as well.
I fell that the setting of the LFO output trimmer, as well as the trimmer for the Lamp Bias would be better if I could set them correctly.
Somewhere there is a set of instructions with either measurements or settings for the various trimmers
Here is my re-draw of the control circuit and trimmer locations. Not sure if I'm 100% correct. If you can, post some closeups of the board from various angles including under the cardboard shield in the middle.
Last edited by dmeek; 11-08-2019 at 11:02 PM.
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