If you hook up the lamp (low wattage lamp) to the two wires of the pump, you should see the lamp goes bright or dim when you turn the Pump control knob up and down. It looks to be just a simple lamp dimmer circuit.
BTW, the two wires for the pump are Blacks, but the two wires soldered to the back of the board are Yellow and Violet?
The resistance of the pump windings are good, not showing open circuit?
I soldered two longer wires to the pump so I could inspect it's operation outside the unit.
The pump seems ok, it measures fine and worked when driven with a series of batteries.
BUT I don't know how I missed this because it was one of the first things I checked when I suspected the pump itself was ok but after all this I found a short from MT2-Gate on the non-heatsinked triac.
I'm going to remove it from the board shortly for verification.
If MT1 to MT2 is shorted then the pump should be on all the time at full blast, same symptom when the TRIAC shorted out in the lamp dimmer the lamp will be on bright.
Something is not making sense here.
The air volume knob was changing the voltage applied to the pump but at 60hz it was just buzzing. Maybe the function of the triac is to change another variable beyond ac voltage ?
The frequency feeding the load (pump or lamp) will be the same as the line frequency.
The Voltage is to the load is the function of the on time of the TRIAC on each half of the cycle.
If the function of the triac circuit is to vary the voltage then it is working except as you say that it may be feeding an overvoltage. I tested the pump itself with batteries and it took about 50v to move the piston sluggishly from one side to the other so it would surprise me if it was designed to work on 24v.
I don't have another triac to install yet would it do any troubleshooting good to move the good triac to the spot where the shorted one was ?
I see DIAC D15 connected to the GATE of the TRIAC and the other end of the DIAC is connected to the RC Phase shift network.
What ACV do you have between the incoming Neutral wire and MT1, MT2?
I see DIAC D15 connected to the GATE of the TRIAC and the other end of the DIAC is connected to the RC Phase shift network.
What ACV do you have between the incoming Neutral wire and MT1, MT2?
I have 120v at MT1 and the voltage at MT2 is variable with the knob on the front, between 60-120v so that seems to be working but something else obviously isn't.
I have 120v at MT1 and the voltage at MT2 is variable with the knob on the front, between 60-120v so that seems to be working but something else obviously isn't.
So do you also see 60~120V between the two wires of the pump?
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