Repairing a Weller Soldering station

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Repairing a Weller Soldering station

Postby gelbanana » Tue Jan 29, 2013 11:24 am

While waiting for ebay parts to arrive for my DC load project, I thought of having a go at attempting to fix the Weller DS701E solder/desolder station which I've gotten it a while back. I have no idea when this model was produced and googling for datasheets and manual comes back with nothing.
2012-04-20_19-22-03_260.jpg


The problem is that readings are way off and all over the place and you can see that the 7segments are actually flickering.
http://www.youtube.com/watch?v=Zs80QPODk_o

My first approach was to look for visual signs of component failure and everything looks fine. So, next is to probe the temperature control board. Check out the old school pcb routing.
The board gets its power from the 12vac through 1/2 wave rectifier, filter cap, 7805 regulator and another filter cap.
Initially, the voltage measured at the regulator was 7v at the input and 4.2v at the output. The filter cap was quite warm.
Tested the cap ESR was 0.7ohms and not shorted. My capacitor meter was only limited to 200uF max. So I concluded that the cap has lost its capacitance over time.
Replaced them with what ever I have in my junk bin and it works like a charm. Did some quick calibration with a thermal probe.
2013-01-28_15-39-46_493.jpg


I've decided to replaced all the caps just in case. Im actually surprised that there are very few ICs in one of these.
2013-01-28_16-00-04_570.jpg


Phillips caps. When was the last time you heard of them? I know they were acquired by some company, Vishay was it?
2013-01-28_16-34-38_151.jpg


An overall shot of the internal. The transformer is rated at 24v 280va. Which took up most of the weight.
2013-01-28_16-00-16_903.jpg


I've also took the opportunity to strip the old paint with a wire brush. Some fine sanding and elbow grease and finally a couple of clear coat. Tried to create the brush alu effect. Unfortunately, the desolder tool wasn't working, it dint get hot but the pump works fine though. Looks like another job for another time.
2013-01-28_22-04-30_489.jpg
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Re: Repairing a Weller Soldering station

Postby katjap » Wed Jan 30, 2013 9:59 am

Despite the VERY (cool) old-school hand drawn routing on the PCBs, I would guess this unit was produced in 1992. (all the IC's have a '92 datecode) ;)
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Re: Repairing a Weller Soldering station

Postby gelbanana » Wed Jan 30, 2013 2:07 pm

Thanks for the heads up. The datecode really slipped my mind.
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Re: Repairing a Weller Soldering station

Postby notthetup » Thu Jan 31, 2013 11:09 pm

Hehehe.. I see Straits Time used to cover the desk.. :P:P
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Re: Repairing a Weller Soldering station

Postby Alex555 » Thu Jan 31, 2013 11:29 pm

Maybe we need lower resolution pics. Some people are way too hyper observant.
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Re: Repairing a Weller Soldering station

Postby presslab » Thu Jan 31, 2013 11:47 pm

I see you have a vacuum gauge on there. If you could, I'd like to know what the maximum vacuum reading is if you cap off the ports with your finger. Thanks!
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Re: Repairing a Weller Soldering station

Postby gelbanana » Mon Feb 04, 2013 9:45 am

notthetup wrote:Hehehe.. I see Straits Time used to cover the desk.. :P:P

Just a matter of time before someone figures it out.

Alex555 wrote:Maybe we need lower resolution pics. Some people are way too hyper observant.

Beg to differ, I actually prefer images where you can really read the printed words on the paper

presslab wrote:I see you have a vacuum gauge on there. If you could, I'd like to know what the maximum vacuum reading is if you cap off the ports with your finger. Thanks!

It can do about 0.5 bar max
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Re: Repairing a Weller Soldering station

Postby peterbj » Wed May 29, 2013 2:26 pm

Thanks for letting us know. I had a look on ebay for some parts but didn't really find anything, are the supplies good quality?
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