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Old 25-08-19, 17:17
David Dunlop David Dunlop is offline
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Join Date: Feb 2006
Location: Winnipeg, MB
Posts: 3,384
Default OS-8B/U Oscilloscope

I have been picking away on this scope lately in my spare time between the usual summertime chores around the house and, quite frankly, the desire to be outside enjoying the back garden whenever possible. I will have 7 more months of indoor time to play with electronics soon enough.

The scope started out working quite well, but over a few weeks I noticed the horizontal controls starting to drop away. Then the vertical controls gave away to the point all I got was a small horizontal trace line at the upper section of the screen that gave me purely random responses to any of the controls. A complete valve replacement did not improve things and I eventually traced the problem to the two electrolytic capacitor cans in the power supply. Both were Mallory Type FP items, one a three section unit and the other a four section.

A little searching on the web revealed a company in the States was still making these capacitors using the original 1920’s equipment from Mallory. And the two capacitors I needed were available with suitable specs AND dimensions. This latter point is very critical in such a compact chassis design. So I shall be ordering a pair of capacitors shortly.

I hope to get the scope back up an running before winter sets in as it will come in handy in testing my two 52-Set receivers.

David
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