This triangle is used to modulate the phaser. The practical upshot of all this charging and discharging is that you should have a rough squarewave at the output of the LFO opamp, and a rough triangle wave at the top of the 10uF capacitor. Once more, the resistance of the speed pot controls how quickly this can happen. Once the cap has discharged the output of the amp starts going positive, and tries to charge it up again. Reduce the value of the resistor, and it will discharge more quickly. With the pot at its highest resistance it can only discharge slowly so the LFO oscillates slowly. As the cap charges up, the output of the amp goes down and tries to discharge the cap through the 500k pot. A proportion of the voltage across the cap is fed into the inverting input of the amp by the 150k resistor. The 500k pot sets the speed, along with the 10uF capacitor. Okay, so what have we got? Well, you'll see that there's an opamp all by itself at the bottom. Since you've only got a single 9V supply from the battery, you can split that and pretend that it has a dual-rail supply. To work properly, opamps need a positive and negative supply. Across that 250k trim pot you should see around 3V - this is used as the "zero" reference for the opamps. The positive terminal of the battery goes through a 10k resistor to a Zener diode (there's also a normal diode to protect the opamps in case you wire the power up backwards). Now, look at the bottom right of the diagram. That's not a great diagram, but it's better than nothing.
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