How to replace Wurlitzer jack springs
A relatively easy DIY to make your Wurlitzer play a lot better
Replacing your Wurlitzer’s jack springs is a great way to improve the feel of your keyboard. Jack springs are always under pressure (it’s the nature of a spring), so it’s a safe bet that they’re ready to be replaced, even if the keyboard is otherwise in great shape.
What is a jack spring? A jack spring is a little spring in the keyboard’s whip assembly that helps the hammer return to its original position. (The whip is the part that forces the hammer to strike the reed after you press a key.) Upright pianos also have jack springs. (Grand pianos have a different design that doesn’t require jack springs.)
Fortunately, replacing the jack springs is a very user-friendly project. If you can get the old jack springs out, the new ones just drop right in (with a little glue to keep them in place). It’s a relatively easy DIY project that will have a big impact on the feel and playability of your Wurlitzer.
Not every model of Wurlitzer electronic piano has jack springs. The Wurlitzer 112, 120, and 700 don’t have them. That’s why these models are somewhat less touch-responsive. In 1962, Wurlitzer overhauled the design of its electronic pianos, and (among other things) added jack springs to the whip assembly. Jack springs work the same way in both 140- and 200-series Wurlitzers, so you can use this tutorial to replace jack springs in any Wurlitzer electronic piano that has them.
Why replace the jack springs? Sixty years later, most Wurlitzer jack springs are stretched out and worn. Replacing them with new jack springs will make the keyboard more tactile, more responsive, and, overall, more comfortable to play. Although the project is time-consuming, the technique of replacing jack springs is not difficult, and it makes such a big difference in playability that we highly recommend it to anyone who has a vintage Wurlitzer. If you’ve regulated your Wurlitzer, lubricated all of the action parts, checked the key bushings for wear, and the keyboard still feels mushy, you would probably benefit from new jack springs.
The biggest difficulty in replacing jack springs is disassembling the keyboard and removing the old jack springs. This is a serious time commitment, so I recommend budgeting at least 2 or 3 days for this project. On the upside, if you can invest the time, it will make your keyboard feel noticeably better to play. For this reason, it’s definitely one of the more rewarding Wurlitzer DIY projects.