Re: 2215 avoiding future CRT damage

Vincent Trouilliez
 

On Fri, Jul 6, 2018 at 11:08 am, zenith5106 wrote:
We set the T/B to the fastest sweep speed with
X10 Magnifier, Hold Off to max, Auto Trig and no input signal. If the trace
could be seen with Intensity set to max , even just quite dim, the CRT was
considered OK.
OK... just perform said test, here is the result :

https://groups.io/g/TekScopes/photo/62323/0?p=Name,,,20,1,0,0

I adjusted the ISO setting of the camera so that the brightness on the pic actually matches the brightness level that my eyes perceive.
That's under normal conditions : a couple fluorescent tubes above the bench for lightning, and me sitting right in front of the scope, at a close but reasonable distance, I mean I did glue my face to the screen...

Looks like an "acceptable" tube then ? I mean it's very difficult to see, and any dimmer than this, would make it invisible but... as you say, you can still see the trace.

Plus, if I turn the var hold-off to the min, brightness comes back to normal, the trace becomes perfectly visible, no effort needed whatsoever.

I will admit I don't really master the var hold-off feature, I am not sure I get why it impacts the brightness level.. but obviously it does. Will need to do some reading and experimenting ! ^^

Anyway, looks like my CRT is not worn out in the end, what do you say ? That's good ! :-)
I mean I have sooo many problems left to fix on this scope, I really didn't need yet another (costly ! ) problem on my list ! LOL


Regards,


Vincent Trouilliez

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