Author Topic: Kikusui analog oscilloscope drifting problem  (Read 2571 times)


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Kikusui analog oscilloscope drifting problem
« on: June 01, 2013, 04:10:16 AM »
I recently got this what I believe to be a product from the mid 80's Kikusui COS5041 analog scope just because being a novice I thought I could learn a thing or 2 from using a less than modern device.

The scope costs me only about 90 odd dollars delivered and appears to be in fair condition, with a sticker that indicates that it used to belong to some university in China.

It seems to function correctly and shows rather accurate measurements when first switched on, as shown in the attached photo where it is showing a 6V p-p 10kHz sine wave on the 20us time base. However, having left it on for a few minutes I noticed that the waveform started to drift. It started to drift slowly lower vertically (Y axis), without noticeable change in amplitude, which I can live with. But the bigger issue is that it also drifts horizontally, at a faster rate as the machine gets warmer, and the measured wave length changes too. I left it on for maybe half an hour and the wave length has increased by more than a division!

I don't have a service manual for this thing but I was wondering if anyone knows if this is a common problem with analog scopes and is it fixable? Any obvious (but safe) steps I can follow to try to diagnose it?

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Email: franky @ 99centHobbies . com