Category Archives: Rants


A review of the “fine European craftmanship” in a French-built oscilloscope 1

A couple of weeks ago my neighbour gave me an old cold war-era analog dual channel oscilloscope, I already owned an expensive Tektronix scope so I decided to take it apart.
The first thing I noticed was that there were no optocouplers present on the E.H.T. * board and after closer inspection I found that the “Focus” and “Brilliance” controls were directly connected to the -2 kV rail and that the user was only protected from these potentially lethal voltages by the plastic knobs on those potentiometers. Obviously this is a very dangerous situation as loss of a knob could result in electrocution.
Another curious aspect of this oscilloscope’s design was the fact that the CRT was mounted tightly into a plastic clamp, possibly causing the tube to break if the oscilloscope was to be exposed to any kind of mechanical abuse, which poses a significant risk to the user as the tube might violently explode when broken.
Besides these safety issues I also noticed a peculiar choice of materials for the chassis and mechanical supports, for simple mounting brackets which did not need to support any weight they chose to use thick pressed steel whereas they used injection-molded plastic for the main structural supports.
When i finished examining the device and tried to reassemble it I ran into a couple of problems: First of all the colour coding was not unique and all of the markings on the connectors were in French, they also neglected to mark the signal and ground pins for the RF connections. Because of these issues I was not able to successfully reassemble the oscilloscope, which however unfortunate, did yield me a very cool, round, Telefunken CRT!
One thing I have learned from this is that something being European made does not inherently mean it is of good quality.