Re: 7104 versions, and vertical amplifier issue


 

On Wed, Jun 16, 2021 at 07:49 PM, cmjones01 wrote:


Yes, I've been surprised by how dim the trace has to be to keep the
"limited viewing time" light off.
These 'scopes are very useful for watching voltage steps. Since the step almost always takes a small fraction of the signal period, average beam current is low. When watching at a relatively low s/div horizontal speed, as is done when checking as you are doing, the average beam current is much higher, so the yellow light, which sort of represents average beam current, comes on rather early. OTOH, MCP wear is not so much a function of average beam current as of integrated secondary emission from each microchannel channel.
In conclusion: The yellow light coming on isn't as indicative of (excess) wear while testing at higher duty-cycle beams. Still, reducing intensity as much as possible is just good practice with these CRT's.

Raymond

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