The screen on our Tektronix TDS210 was lacking brightness and contrast, so we thought it was probably the backlight.

After some trawling around online we discovered it was fairly easy to replace.

The digital operations were converted into a Boolean logic map, and subsequently implemented using diodes and SPDT switching relays. The advantages of this approach are manifold, as standard automotive five-pin micro relays are readily available at any auto-shop and the diode assemblies used to create ‘OR’ gates, although custom, are small, cheap, easy to carry as spares, and are fitted to plugs, making the LRU of the unit a fuse, relay, or a diode gate, any of which can be replaced in a few moments without tools as a roadside fix.