Weller PU81 station mod for DSX80 desoldering handle

[futurist]

Just to quickly share my latest project

I have Weller PU81 soldering station and after watching video on Marco Reps's channel I decided to buy DSX80 desoldering handle. It's completely compatible with my station, heating control works out of the box, and the only thing needed to get it running is to add a vacuum pump. I decided to try small 12V vacuum pump https://www.ebay.com/itm/DC-Electric-12V-Micro-Vacuum-Air-Pump-Booster-For-Medical-Treatment-Instrument/282489988597 which is just 3$ delivered, and could even fit in the station.

For pump speed control and 24V to 12V regulation I decided to make a small 50x50 mm PCB with 555 PWM and LM2596 DC-DC converter





BOM, gerbers, KiCad project of the module are free to use
buck_pwm_module.zip

Next problem is how to use internal switch to power the pump


There is no way to use the switch directly. Hydron proposed neat solution using AC relay connected to one of the terminals of the transformer and pin 7 on DIN connector (pin 6 on official Weller pinout)

24 VAC relay


Wires for the relay


Biggest part of the job was to fit everything inside existing station enclosure because free space is very limited. Friend helped with drawing models for mounts for the AC relay, PCB and vacuum pump



PCB


Vacuum pump mount


Before soldering


.stl files for 3D printed mounts
mount.zip

Hope someone finds it useful

[oneKone]

I didn't even know desoldering stations existed! How does it perform compared to a spring loaded solder sucker?

[futurist]

It's not magic bullet but because the entire tip is heated it's much better than hand held vacuum pumps
Downside is cost, complete Weller WDD 81V desoldering station which needs compressed air to operate is 790 €, and just the handle is ~250 €. I got lucky on eBay and bought new handle for under 150€, which is still very expensive but since I won't be using it on a daily basis it should easily outlast me

[Mads Barnkob]

Great project futurist! Rebuilding equipment to expand the features a lower cost is the essence of what we do

[futurist]

Thanks Mads!

Short update on the project
Today I made a simple hose adapter which replaces key plug on the soldering station and allows the DSX80 handle to be connected externally
So far everything works nicely and the small vacuum pump doesn't have any problem sucking the solder. I added fuel filter before the pump to prevent any flux vapor from entering the pump

.stl file of the hose adapter
hose_adapter.zip

[Mads Barnkob]

That is a clever use of a existing product, the gasoline filter, instead of trying to come up with a complete new solution. Its cheap, common and easy to replace

Still working good some 2 weeks into use?

[rafscipio]

I register to this forum, just to thank Futurist for sharing this cool project.
I already have a Weller WR2 station with desolderin iron DSX120, and i like to have a second one.
Very well done, i'll try to do a similar one, maybe just using more powerful pump: watching your video and comparing to my original, i believe it works better with more suction

[UpperLeft]

Hi there,
I also use a PU81 (as well as a WSD81) to run a DSX80 desoldering iron. Since I was never able to tap the push button of the DSX80, I switched the external pump with a foot switch, wich woks well - but using the DSX80s push button is of course more convenient.

So yesterday I found your article and rebuilt everything as described - only it does not work. Between purple (the "middle" pin no. 7) and 24VAC tap direct from the transformer, I always have 24VAC (even without pressing the push button) - therefore my ac relay is always energized. I tried it on both of my soldering stations - always with the same result.

I just don't get it: The DSX80s blue wire / pin 1 (same level as the 0VAC tap on the transformer) should be bridged (when pressing the push button) to the purple wire (pin 7). I even desoldered the 44K resistor in the DSX80, which made no difference at all.

I must be overseeing something elementary - any help ist welcome.

Kind regards
Jan

[Hydron]

I gotta admit that I've mostly forgotten how I did this - certainly need to get better at documenting projects, it's bitten me more than once when trying to fix/change something years down the track!

I can assure you that it's possible though, and not just with the relay solution (this was simply the easiest for futurist's setup - I did it differently, with a bridge rectifier, optocoupler and resistor driving the pump PSU enable line _I think?_)

For reference, this is what I ended up building:



Everything except the filter and iron were salvaged parts, so it was cheap to build but certainly time consuming!

[futurist]

You can't use handle switch directly, did you try using relay or you connected the pump directly?

Hydron can you remember why didn't you use relay?
Mads, everything still works fine!

[Hydron]

I think I didn't use a relay because I had the parts on hand to do it another way, whereas I would have needed to order and wait for a relay.

I am using the button to enable the buck converter I'm running the vacuum pump from. This way it only needs to switch a small current.