Back in 1978, an oscilloscope was an exotic piece of gear for most homebrewers. We expect they were even more rare in private hands behind the iron curtain, and [Thomas Scherrer] shows us a Soviet X1-7B combination oscilloscope and spectrum analyzer (he thinks, at least, it is a spectrum analyzer) that he got working.
The Soviet scope is clearly different with its Cyrillic front panel. Luckily, Google Translate was up to the task of decoding a picture of the device. However, the differences aren’t just cosmetic. The scope also has a very interesting rotating bezel around the round CRT. You can see a video of the 8.2 kg scope below.
A quick look inside looks pretty conventional for a scope of that era that used all transistors in the circuitry. The rotating bezel, though, also controls something that looks like a big mechanical switch and cavity or, perhaps, a big mechanical variable component of some kind.
Satisfied that the insides were in reasonable shape, [Thomas] was ready to try turning it on. We want to say it went well, but… there was censored audio, along with a loud noise, right after it was plugged in. Troubleshooting centered on what was producing a burned smell, but a quick examination didn’t turn up anything obvious, despite being localized to the power circuitry. The fuse didn’t blow, oddly, and — even more puzzling — the unit was off when plugged in!
It turns out the input power filter leaked to the chassis. Since he had a ground on the chassis, that explained the failure, and while it ..
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