Weller: The Final Chapter

Well, I hope it is the final chapter. I’ve written before about fixing and then learning that I hadn’t quite fixed my Weller WESD51 digital soldering iron. After much manipulation, I think I ended up cooking the PIC chip on the PC board, so I just ordered another board. Long story short: replacing the old board with a new one worked and I now have a functional solder station. I have some details below about where I ordered the replacement board and how I installed it in case anyone runs into a similar situation (or, given that cyclone season is again upon us with massive voltage fluctuations on the mains, in case my unit gets toasted again and I need to follow my own instructions).

First, where to order replacements. I have the 230V model, which is less common and the price varies greatly on the internet. I got the backup board, WES207 from Test Equipment Depot for the very reasonable price of $30 USD.  In fact, they had the part when Weller itself wasn’t able to supply one, and even when in stock at Weller, they were going to charge me $15 more. So much for going to the source. Incidentally, the price for the whole unit including the iron at Test Equipment Depot is $154 USD, which again is the best price I’ve seen online. Aside from price, their service was great and delivery was rapid, so I was very happy with them.

There isn’t much in a WESD51 power supply.

In fact, it’s tempting to say that for $30 bucks you could order the board, put it in a case, wire up power and the iron, and have an equivalent functioning unit and save at least $100.  The station consists of a bottom unit with the transformer, an upper case shell, and the front panel, with its display, knob and mounting holes for the PC board and DIN connector for the iron. The PC board is held in place with two screws and the dial. The screws bite into short plastic posts, so it is best to minimize the number of times the PC board is detached and reattached.

Connections to be made include two pink wires from the secondary side of the transformer to the bottom of the PC board, tabbed power connectors to the switch from incoming mains voltage, and five wires that run to the DIN connector for the iron. Those DIN connections are the trickiest part – the wires terminate in a crimped connection which is barbed. The old wires can be pulled straight out, but one of them left behind the connector, which had to be coaxed out with a jeweler’s screw driver. I was afraid that the plastic holes might be damaged, but they survived. The replacement wires need to be inserted carefully because the small crimped ends can easily bend, and no replacement connectors are supplied.

When reassembled, the soldering iron connector fitted easily on to the base unit, and when powered up, the display came to life. I’ve now been using the iron for a few days, and it is as good as new.