Reverse Engineering Saves Weller With A Wonky LCD From The Trash Pile

There’s nothing more satisfying than finding a broken piece of gear in the trash and bringing it back to life. Satisfying, but also potentially more time-consuming — someone tossed it for a reason, after all. Figuring out what that reason is and finding a way to back it better is where the fun — and the peril — are.

Luckily, some pieces of equipment have a relatively short list of well-known failure modes, a fact that [Lauri Pirttiaho] relied on for this fix of an old Weller WD1 soldering station. The unit, sporting the familiar light blue Weller livery and more than a few scratches and dings, had an LCD that was DOA. Typically it’s the driver that’s the problem here, but [Lauri]’s diagnosis revealed it was the LCD module itself that was bad.

With OEM replacements being basically unobtainium at this point, the fix was to intercept the data heading from the driver to the old LCD and send it to a new, easily sourced 16×2 character LCD display. This began with an inspection of the display controller’s datasheet, and a bit of probing of the old display to find out which segments and backplanes map to which pins. A little bit of case modding allowed the new display to fit, the old controller chip was removed, and a PIC16 went into its place, in a tidy nest of Kapton tape and bodge wires. The PIC does the job of translating the original display, which had a fair number of custom icons and symbols, into sensible text-based equivalents and sending them to the 16×2 via I2C. The video below shows the hack in action; it honestly looks like it could have come from the factory like that.

The nice thing here is that [Lauri]’s fix applies to a whole range of Weller stations, so if you find one in the trash, you might be able to resuscitate it. Failing that, you could always roll your own Weller from (more-or-less) scratch.

15 thoughts on “Reverse Engineering Saves Weller With A Wonky LCD From The Trash Pile

  1. What a sweet hack!

    I still use two no frills 24VAC Weller Magnastat irons from the mid 70s and mid 80s with constant temperature tips. They made absolutely indestructible tools back then.

    1. Another happy WTC user. Mine came from Data General in the 70s. It’s the old kind, skinny, with the hard thick plastic base. I don’t think it even had a power switch or LED…so I added them. It lives out in my garage and has for years. I believe it will outlive me.

      1. I guess they really will. There’s loads and loads on eBay, Craigslist and whatnot and there’s even adapters to use newer Weller tips.

        I really see absolutely no reason to switch to something digital. These stations are 35-50€ in a good used condition and I use 370°C for everything since I started soldering at age 13 (35 now). You learn to solder accurately and quickly that way…

        What is neat too: those irons work on 20V tool batteries quite well. I’m using them on the go, too. There are reports that the magnastat mechanism has lots of wear using DC but mine still works :)

        1. Don’t try the JBC stuff then, once you have 200W on demand at the end of a needle tip you will never look back. You can desolder D-PACK within few seconds with theses…
          That’s a pity cartridges are in the 30€ range.

  2. ” someone tossed it for a reason, after all”
    Yes, because of ignorance or stupidity. Sometimes i find completely working gear in the trash, or with minor defects.
    Would be better if the owner sells it because sometimes any spare parts are only available via salvaging.

    1. My JBC came from the bin. It’d got dropped in the lab and the corner of the case broken off. Not cost-effective to investigate and repair, let alone the indirect expense of the downtime. Much more efficient to just buy a new one for next day delivery.

      I’ve meant to fix the case up properly for about 8 years now, but the electrical tape hasn’t fallen off yet.

    2. Our hackerspace almost tossed a WD 1 station because it was in the software power-off mode, which is entered and exited by holding down both arrow buttons. A quick read of the manual and it was operating perfectly :)

        1. a lot of their irons do this and if uniniated it just blinks a number at you then goes dead, so yea a lot of people would think its broken. what’s worse is they change the key combo… most of them we have around work is the up and down arrows, then we got a newer one thats the left and right arrows (on a touchscreen no less)

  3. This post started with the statement nothing more satisfying than. I have to disagree some. My reason for this is that I have experienced this and I have also experienced finding a perfectly good Craftsman battery power circular power saw in the dumpster here not that long ago. Now this tool is the older 19.2V version of which I have had a few of the drills and other tools of that style, I’m now on my second saw.. 3rd drill I think. I now have a repaired drill, needed another switch which I found a site on ebay that sells them plus a quick change bit driver all use the same battery. I bought a new charger and a pair of new Li-Ion batteries to replace the NiCad’s that died few years ago. Those old OE chargers had issues with heat and the plastic piece that worked the switch in those would crap out and the chargers were pretty much useless since Sears has such a lousy parts replacement arrangement.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.