The volvo has been a really rewarding project, and I've finally gotten around to taking some photos. 1974 was the first year Volvo put Bosch fuel injection in these cars, but I think the next step for this one is a Weber conversion. In the meantime, if you're reading this and have any experience bypassing K-jet thermo time switches to some kind of manual toggle, email me!

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Dead speedos and tachs are common on older cars with electronic instruments. With some soldering skills and a basic understanding of circuit board components, you can easily avoid spending hundreds of dollars on repairs or replacements. This fix cost me a Saturday afternoon and less than $10 for a handful of components.

After removing the circuit board from the tach, look for any visual sign that something bit the dust. This could be corrosion or burn marks from something shorting out. Capacitors will often bulge on top or bottom when they're blown. Two of these capacitors had some corrosion on them, and a quick test with a multimeter showed they were faulty. New ones cost less than a dollar, but how do we know what to buy?

So in this instance, we need a 47 µF capacitance, 25 volt capacitor. We can head down to Radioshack or do a search online, and... Look what we find! A grand total of 47 cents. You might run into other symbols such as tolerance (+/- X%). Ceramic capacitors have their own codes entirely. Here's a friendly guide for those. The small components with the multicolored stripes are resistors. There's a handy guide for understanding their color codes here, and a guide for identifying other components here.

Another likely culprit is the potentiometer. Potentiometers are used to adjust electrical resistance. If we think of electricity as water flowing through a pipe, resistance can be thought of as the diameter of the pipe. A smaller diameter pipe restricts water flow, much like more resistance restricts electrical current in a circuit. When you use a volume knob or dimmer switch, you're most likely using a potentiometer.

In this case, the potentiometer is used to calibrate the tach once it's put back together. The replacement I got has a range of 0-300 ohms and is adusted with a screwdriver. You can see it in action by connecting the terminals to a multimeter and turning the wiper. I'll be posting the installation and calibration process soon.

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I built this credenza after seeing a similar project done by Morgan Satterfield of The Brick House. I started with two Ikea Besta cabinets as a base and wrapped them in pine. This thing is over 8 feet long and I move pretty often, so I wanted to keep the cabinets modular. The entire thing can be split in two and the legs are easily swapped out for different lenghts.

Push openers allowed me to entirely wrap the cabinets flush with the doors without installing handles. Not shown here is an extra door I made by stretching white speaker cloth over a 2 inch frame to allow for home theater equipment remotes and displays.