Hi guys.
This is my first post here so, a bit of information about me: I'm 21, looking to gain more knowledge about electronics. I am working in an A/V rental company and I need more expertise to be able, someday, to make my own hardware.
So.
For a few months I worked in a repair company that had a Weller WMD3, with a DSX80. (and a WSP80 but for some reasons I don't like it)
I loved this thing, it made recapping a lot easier. No more lifted traces, destroyed pads... You know the drill.
Wanting to have one at home, I started to look around for used units on the fleabay.
I love good tools, and boy o boy, you know they ain't cheap, but the WDD81 (the desoldering station) alone being 500$+, added its DSX80 iron which is going for around 200 bucks new on buy it now listings, was very cost prohibitive for me.
I started to look for cheaper options, but nothing gave me this impression of quality like the DSX80. So as it was not in my priority list, i skipped it for a little bit.
Someday, in a more or less recent past, I was wandering around on YouTube and I came across a video of Marco Reps about a WSF81D mod to add a vacuum pump.
This mod is using the solder feed output to drive the external pump (pretty clever I must say, this even allows the station to adjust the PWM duty directly via its interface)
This is great !
... Unless if nobody sells them.
Somewhat expected, as this kind of equipment is meant to be used in assembly plants.
So, i wander around a little more, and I found a listing for a WSD81 mainboard, bare. No casing, no transformer, nothing.
I quickly convince myself i'll figure something out, and as this was cheap, 30 bucks, i bought one.
One month later it shows up at the door, and here it is :
So it wasn't a scam, they scrapped WSD81s.
What do I do now ? I don't have anything to test it !
...
The DSX80, in all its glory, delivered in one piece by DHL. The seller didn't even use bubble wrap, the box was just wrapped in newspaper and packing tape. I'm glad I use PayPal sometimes...
All its accessories/consumables. I'm just missing the stand, which I will buy soon.
I may have gone a bit overboard on the transformer rating, but the iron and the controller themselves are eating around 90 watts.
If I want to be able to supply enough current to my 40 watt vacuum pump, I will need more than 130 VA. As 120 VA seemed a bit too small (maybe just right, I will never use the pump at max airflow anyway) I took a 160 VA one.
It is a Vigortronix VTX-146-160-212 for those who wonder. Quality and insulation seems ok.
I also bought the vacuum pump, a chineseā¢ VN-C4 which was surprisingly hard to find with a 24v motor.
The pump inside the WDD81V is a 35L/min, 55 kPa one.
This was the closest one that I found in terms of airflow, but it had a higher suction rate, 85 kPa. I'll take it, we'll see how it goes.
They even spelled "Model" wrong. Oh god what am I complaining about, that's the one and only
Made in Chian quality seal.
Bent pin included for scale. Nothing a pair of pliers can't fix, right?
Anyways.
This is great but I don't even know if my motherboard works! And I know even less how will I drive my pump.
For the motherboard, it's simple, I just need to hook up the transformer to the controller and that should be it.
It will allow me to drive the iron, who should work even without the correct station. After all, it's just an expensive German-made resistor.
I'll do it. I'm just lazy. But i'm pretty confident that my controller should work.
For the pump driving part, that's a bit more complicated, but after a bit of Google-fu, I found this :
Weller PU81 station mod for DSX80 desoldering handleThis is cool. That's what I want ! But unfortunately as this was made to fit inside the station, it will require some additional bodges and I don't want that. Also it didn't supply enough current for my pump.
So I decided that it was the time for me to take the plunge and learn how to design a PCB.
I fired up Eagle, watched tutorials, and started to re-trace the schematic that Futurist uploaded on hvforum.net. As he kindly provided his work as open hardware, and because my project is a fork of his, it will be a open hardware project too.
Here is Futurist schematic :
Here is my piss-poor redrawn schematic (i hope you do not mind some double traced nets, this is not OCD approved for the moment, i'll work on this later
)
I needed to replace some components that weren't available for me. I guess Futurist did with what he had on hand for some things, but I may be wrong,
that's where I need you - I replaced the DSF1J diodes who appear to be the part number for chinese made S1A-S1J series diodes. The choice of the F1J seems a bit weird to me, being used in D1 as a reverse polarity protection diode (?) and D2 & D3 as the astable multivibrator for the NE555 there is no need for a 400v diode.
D1 would need to be able to withstand the 1.5 amps for the 7805, D2 & D3 as they are for the astable, they need to be able to block Vcc, and be fast. Correct me if i'm wrong, S1B diode with 70V Vrms and 1 amp If should fit
I have seen that the 1N4148 is somewhat a better choice for astables, because it has a reverse recovery time in nanoseconds I guess. Is the diode speed related to how "sharp" will the PWM look?
- For D4 and and D5, I need a schottky diode with Vrms greater than 24v and If greater than 2A (or should it be able to withstand all the current of the LM2596?). It seems to me that the MBRS340 would fit here.
Also, what is the purpose of D5?
- I also need to replace the AP9985GM-HF 40V N-channel mosfet. I think that the DMN4026SK3-13 can do the job, 40V Vdss, it's Rds is higher than the AP9985 but I don't think that it will cause a problem, the higher the Rds, the higher the efficiency if I am correct?
Do I need to change the value of R2 here? As Rds is higher?
If someone could take the time to answer my questions, that would be really helpful.
I'll work on the schematics a bit more to get them right and i'll get on the routing this week end hopefully.
I will share the project files when they will be clean.
Many thanks in advance