Rework Station Pump - Can They Be Repaired ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

i have a funny feeling the motor control is a phase-angle controller - like a lamp dimmer.
you will need a scope to see what it does, BUT maybe replacing the pump with a low wattage lamp bulb would be a good test.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Resoldered the two triacs, the lm358 and several dubious joints. Reassembled the pump unit minus the back plate so I could see the movement of the piston.

Fired it up and no change.

The frequency was measured at 60hz. The a/c voltage changes with the air speed knob but the frequency remains at 60hz.

I noticed now that the wand no longer heats up, don't know how long it's been like that or if it's a related problem yet.

Feel like I'm chasing my tail with this one.

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

resolder the power transistor or whatever it is,
the center pin looks strange in the foto's

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

The two soldered to the back of the board in pic 4 and pic 5.

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

so which pair of wires goes to the pump?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Here are some pics of the control board. It has two bt137 triacs and an lm358 on it as well as a/c input from the mains. Can anyone infer from the pics how this works ? And is it safe to put a scope on the two wires driving the magnetic coils ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

put a microphone near it - if it's between 50Hz and 15KHz it should detect it.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Hmm.. will try with a compass though the frequency of oscillation may tear the needle off

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

I have verified with a magnet that the two magnets on the piston are indeed in the arrangement as posted above.

I need to recheck the coils to rule them out. After that it's a problem on the driver board - will post pics of that board soon.

Is there an easy way to test for the presence of an oscillating magnetic field ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

start with a re-cap

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Ok this image is from a patent filing and so the mystery is solved on how this is SUPPOSED to work. Now to troubleshoot if it's mechanical or electrical.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

The coils are wired in series.

[harleyman58]

Re: Rework Station Pump - Can They Be Repaired ?

Why are there different wires feeding each end of the coil? With the commons wired together?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Yes the coils are energized at the same time. Seems to me the magnetic field is perpendicular to the path of the piston though. Or is it ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

no, both ends energize together.

what may be happening is that you have a pair of magnets of oposing polarity's, so it will pull in the direction of the current flow.
that just happens to change direction 50-60 times a second

[harleyman58]

Re: Rework Station Pump - Can They Be Repaired ?

One coil energizes pulling the diagram to one end,then it shuts off and the other coil energizes pulling it to the other end. Then the coils just alternate off and on.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

I considered this but I am not fluent in magnetics lol.

If the two pieces in the piston are supposed to be steel (they ARE magnetized atm) by what mechanism does the piston move to the other end of the stroke ?

[harleyman58]

Re: Rework Station Pump - Can They Be Repaired ?

The piston that has the diagrams on it will not be a magnet. The coil creates a magnetic field pulling the iron core in the center to one end of stroke then the other. If it was a magnet it would not move because of opposing magnetic fields.

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

that's very different, but shares the same construction quality!

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

I couldn't do it either. I will pull the board and have a closer look and check some of the components.

The magnets look good.

stj there is a photo on the first page of the circuit board. Will take a better one when I remove it.