Re: Timebase and CRT Issues on Tektronix Type 545A


On 21 Mar 2016 16:49:36 -0700, you wrote:


Never mind, I had never seen bumble bee capacitors before I Googled them. They are all over the place. I'll have to look into buying a jumbo set of capacitors, it looks like. Is there a preferred replacement? Electrolytic, ceramic, polyester, etc?
I forget exactly who but the bumble bee capacitors came from one
particular manufacturer (Sprague?) of oil and paper capacitors and
earned the name just because of their looks. All paper and oil
capacitors suffer from the same problems though. I have had to
replace a few myself.

Polyester film would be the natural and superior replacement. Ceramic
capacitors could be suitable in some applications.

The ripple in A seems to go away after the unit running for around 15 minutes.

I think somebody earlier mentioned a tube tester. I do not have one personally. Could a dead tube render Timebase A inoperable? Is there a visual check that can be done on tubes to find out if they are dead? The trouble with Timebase A is that is harder to work with than Timebase B, which just swings out. The tube part of the Timebase A circuit is upside down, making it harder to see the tubes.

Alex Brinister
You will not be able to visually find bad tubes unless the failure is
an open heater.

Someone more familiar with the 545A will have better troubleshooting
suggestions. I have not used mine in a while.

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