W1WRA'S Floobydust

Bringing life back to old oscilloscopes


Several weeks ago I got a notification from a friend about someone who wanted to get rid of some “electronic junk” from an outbuilding of a property they had just recently purchased. The pictures I was sent had some CB stuff, a large steel rack, and some interesting power supplies, but was caught my eye was a couple of oscilloscopes. I thought the trip would be worth the scopes and power supplies so I hopped in the truck and went to grab the gear.

Upon arrival, I found there were actually 3 oscilloscopes, as well as some mystery home-brew stuff (perhaps a future post) and other items. So after loading and then unloading the truck, a task easier said than done due to the monstrous steel rack, I took the scopes inside to be inspected.

I have only “worked” on one thus far: The B&K Precision 1461. This is a simple 10 MHz single-channel scope.

With all the dust, etc I had no idea how the first scope would be. As one probably should in these matters I connected up the scope to a variac to slowly bring the voltage up on the unit. I was pleasantly surprised when at about 25-30 volts AC I saw the power lamp light up. Perhaps there was hope for this unit after all. After some time had passed and the voltage slowly increased to about 70 volts AC I was surprised at seeing a trace appear on the scope.

At mid-intensity, a nice strong trace indeed. I calibrated one of the voltage settings on the unit and eventually figured out how to straighten the trace. I originally was over-complicating things. There were 2 set screws in the rear of the unit which allowed for the tube to be easily rotated.

After hooking it up to a signal generator, looks like things are displaying nicely.

All that’s really left to do is a dust cleanup, apply some DeoxIT on a couple of the pots, and walk through a complete calibration of the unit. After another quick “burn-in”, I’ll move on to the next scope.

One of my intentions in grabbing these scopes was to gift them to some ham radio operators in my local ham radio club. An oscilloscope is a great tool to help visualize things in electronic and RF circuits. Hopefully, the visualization will help spark more interest in diving deeper into some of the technical aspects of the hobby.

1 one, 2 to go.

#electronics #oscilloscope