Rework Station Pump - Can They Be Repaired ?

[mmartell]

Turned on my 852+ clone the other day and the unit made a damn racket. Noticed quickly there was little to no airflow out from the wand nozzle and shut it down.

It seems there are seals at the diaphrams that are know to melt or otherwise malfunction but parts are all but impossible to procure.

Has anyone rebuilt one of these with off the shelf parts or should I start looking to replace the whole station ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

you can get the pumps cheap,
but did you take it out yet? they can crack - and be sealed.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Taking out the pump soon for inspection. Where do you see them for sale ?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

chinese places.

*if* they are over $20 then buy a new unit with a fan in the handle.
this goes nicely wih it.
http://www.eevblog.com/forum/reviews...stom-firmware/

[clearchris]

Re: Rework Station Pump - Can They Be Repaired ?

You can also replace with an air horn pump. Check the voltage though.

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

You can also replace with an air horn pump. Check the voltage though.

no you cant, that's a hot-air unit - not a solder-scker.

[clearchris]

Re: Rework Station Pump - Can They Be Repaired ?

Oh, woops. You are correct.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Had a closer look at the diaphragms and I see no evidence of degradation or tearing. Will remove the bottom plate and check the motor itself next. Looks like these motors run off line voltage intead of the 12v I was expecting.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Removed the diaphragms and the bottom plate. The piston vibrates but does not move back and forth like it should. I can't yet tell if there is a track it should move in or moves just by magnetics ?

It seems like the diaphragms are weak, not torn in any way but too pliable. If these are meant to keep the piston in place then they are too weak as I can easily move the piston up and down with light pressure.

Any thoughts ?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Should the diaphragms be strong enough to keep the piston from being pulled sideways to one of the coils ?

[xelectech]

Re: Rework Station Pump - Can They Be Repaired ?

Should the diaphragms be strong enough to keep the piston from being pulled sideways to one of the coils ?

How 'bout a picture or 2?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Yes good idea. Will put some up later today.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Some pics... they've all been rotated, yay.

The first pic shows the core with dual coils wired in series. Both coils ohm out to about 146ohm so I think they're good ??

The second shows the "piston" with dual magnets.

The third shows the piston inserted between the coils.

The fourth is the housing that the assembly slides down into.

The fifth is the control board.

There is no "track" or discernible way for the piston to be kept in place. In pic 3 the magnets are easily drawn to the core so when the whole unit is assembled they remain bound to each other such that no movement is possible whether power is applied to the coils or not. This is what makes me think the diaphragms (damn, pic coming!) should be stiff enough that when assembled they keep the piston BETWEEN the coils.

I'm sure someone here knows the precise theory of operation here so help me out. Are the diaphragms to blame or something else ?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Diaphragms. You can see in the third pic how easy it is to distort them with one hand.

[xelectech]

Re: Rework Station Pump - Can They Be Repaired ?

Some pics... they've all been rotated, yay.

The first pic shows the core with dual coils wired in series. Both coils ohm out to about 146ohm so I think they're good ??

The second shows the "piston" with dual magnets.

The third shows the piston inserted between the coils.

The fourth is the housing that the assembly slides down into.

The fifth is the control board.

There is no "track" or discernible way for the piston to be kept in place. In pic 3 the magnets are easily drawn to the core so when the whole unit is assembled they remain bound to each other such that no movement is possible whether power is applied to the coils or not. This is what makes me think the diaphragms (damn, pic coming!) should be stiff enough that when assembled they keep the piston BETWEEN the coils.

I'm sure someone here knows the precise theory of operation here so help me out. Are the diaphragms to blame or something else ?

Strange looking motor, for sure, I've never seen one like that. How are/were the diaphragms attached to the spindle? Just a guess, maybe each diaphrapm was ultrasonically or chemically welded to the black piece on each end, which made them stiff enough to keep things in place.

Looks like some kind of deposit on the control board, what do you reckon that is?

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

the white is flux that got wet because they washed the pcb without removing it all first.

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

The diaphragms are mounted to the spindle by a small nut, and secured around the perimeter by the chambers that get screwed down over them to the main assembly.

Stab at theory of operation - the coils receive a pulsed voltage pulling one of the the piston magnets in line with the core providing a full stroke in one direction. When the pulse abates the piston returns to the center position where the next pulse pushes it further in that direction until the second piston magnet is in line with the core and the cycle continues.

Is any of that correct ?

[mmartell]

Re: Rework Station Pump - Can They Be Repaired ?

Is it safe to hook a scope to the coil source ? Maybe this is missing half the wave...

[stj]

Re: Rework Station Pump - Can They Be Repaired ?

i would say the diaphrams have somehow broken loose from the pole-piece.

[xelectech]

Re: Rework Station Pump - Can They Be Repaired ?

The diaphragms are mounted to the spindle by a small nut, and secured around the perimeter by the chambers that get screwed down over them to the main assembly.

Is it obvious how this thing built pressure, ie reed valves or some other separate mechanism, or did it depend on those holes in the diaphragm to somehow do the job?

Stab at theory of operation - the coils receive a pulsed voltage pulling one of the the piston magnets in line with the core providing a full stroke in one direction. When the pulse abates the piston returns to the center position where the next pulse pushes it further in that direction until the second piston magnet is in line with the core and the cycle continues. Is any of that correct ?

I was thinking it was just running mains frequency thru the coils, doing cycles of attraction/repulsion, but I could be wrong and you right. That motor is really cool, though, must be nearly zero friction when it's working...