Pace dual-path desoldering station from eBay - it blows instead of sucks!

[ockerbill]

Hey Folks,

I'm hoping this is a dumb question. This thing is blowing air from the vacuum point, anyone seen this?

It also is missing it's vacuum control valve (which seems normal on many ebay listings), the seller said it doesn't affect operation.

- Bill

[Falcon69]

Some vacuum pumps can do both. Simply take it apart, and turn the valve/diaphragm assembly around 180 degrees.  Tetra Aquarium pumps are real easy to do this with.

[Riotpack]

Maybe you are using a northern hemisphere desoldering station in the southern hemisphere?

[ockerbill]

The weird thing is, it seems to be sucking solder, there is solder in the glass tube and filter. How is this possible? aaaagghhh!!

[ockerbill]

Maybe you are using a northern hemisphere desoldering station in the southern hemisphere?

hahah nice one!

I actually used to use Pace desolderiong stations when I was a tech in the RAAF (Aussie Air Force) but now live in the USA. So in this case, the hemispheres are in alignment!

- Bill

[tautech]

The weird thing is, it seems to be sucking solder, there is solder in the glass tube and filter. How is this possible? aaaagghhh!!

With the valve missing it sounds like you have a "half-wave" vacuum.

[BennVenn]

yeah, add a piece of tuned length hose to it and you'll make yourself a resonant circuit, like extractors on an engine

[Falcon69]

Maybe you are using a northern hemisphere desoldering station in the southern hemisphere?

LOL, funny. I think maybe when you take it apart to inspect the valve assembly/diaphragm, you should use a Left Handed screwdriver.

[helius]

The Pace stations that I've seen have both an air input and output, labeled with little arrow symbols. Only the air output has a speed knob around it. Are you sure you're using the right port?

[ockerbill]

[helius]

Right, I wasn't sure if the markings had worn off  That's an older Pace unit, the newer ones use graphical symbols to mark the ports.

Inside you'll find a reciprocating air pump. One of the ways they can fail is the rubber check valves drying out, which would cause the symptom you're describing. I would take the pump out and disassemble it as far as the valves, see what shape they are in.

[ockerbill]

I took the pump apart, and there a simple diaphragm which pulls in and out from the action of cam-like device attached to a fan. The diaphragm looks pretty good, in that it flexes. and I can't see any rips.  On the other side of the diaphragm is a block with the vacuum and pressure ports with what looks like a sealed rubber diaphragm. It doesn't appear to be removable.

What I also found is that although the vacuum seems to be pushing air, at the glass tube on the end of the hose, there is suction if you block with your finger.  I recall the suction being great back in my tech days using a Pace station.

[amyk]

What I also found is that although the vacuum seems to be pushing air, at the glass tube on the end of the hose, there is suction if you block with your finger.

I haven't used these before, but could it be a venturi pump type of arrangement?

[ockerbill]

I kept thinking a venturi may be involved... I'll keep you posted on what I find.

[BurningTantalum]

All joking aside- If you have the tubing connected correctly externally, (and on my MBT100 the 'blow' port has a simple pressure regulator that doesn't really work very well,) then the pipes internally are connected incorrectly. Easily done and easy to suss with a finger.
 Just remember to get into the habit of 'over-running' the suction by a couple of seconds after you have removed the tip from the job. If you don't, the hole will block quickly and frequently and will drive you nuts cleaning it out. Plus eventually you will drop the pyrex tube on the floor and break it...

BT

[ockerbill]

Sorry folks, work pulled me away.
This baby works great now.  Stupid me, did not have the glass cylinder fully engaged. So all is well.  Still weird that it was blowing though,, it must just be the way the pump works....