Maker as Fixer: Repairing a Racal-Dana 1992 Frequency Counter
Or how to turn used, non-functioning equipment from eBay into a fully-functional workbench appliance for your maker studio – Kerry D. Wong makes the difficult-to-decipher easy to digest and learn from his walkthroughs and videos (the first portion of the video below will introduce you to frequency counters if you’re interested). And you find some intriguing stuff along the way like that NE521 sub-circuit!
I picked up a non-working Racal-Dana 1992 Frequency Counter on eBay a few weeks ago. The symptom is that only channel C seems to work correctly and neither channel A or channel B produces any measurements. Since the majority of circuitry is shared among all three channels, it is most likely that the fault is localized within channel A and/or channel B. In this blog post I included many teardown pictures taken during the repair and a video detailing the process is included towards the end.
Racal-Dana 1992 universal counter has three independent inputs. Channal A can measure from DC up to 160 MHz, channel B can measure from DC up to 100 MHz and Channel C has a range from 40 MHz all the way up to 1.3 GHz. Besides frequency measurements, frequency ratios between two signals can be measured via channel A and B or channel C and channel B. Phase relationships between two signals can also be obtained via the A/B channels.
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