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2467BHD does xy-mode as single sweep event, continous display missing


Andreas Ragner
 

Hi,
my 2467BHD does the xy-mode as a single sweep event. The continous display of the waveform is missing. After switching the horizontal timebase to XY, a short blink of the expected waveform is immediately displayed, and immediately too the waveform disappears. All other timebase settings (and every other function of the scope too) work fine. The erroneous behaviour can be repeated as often I like to do so. Maybe someone knows this strange phenomenon, and even better a fix for it.

best regards,
Andreas


Andreas Ragner
 

Hi,

today I found the fix. It seems the 2467 is disabling the MicroChannelPlate-electrode for intensity amplification in xy-mode. I guess this is implemented for longer CRT health. Therefore the beam is much, much darker than in normal timebase settings. Massive ramping up the intensity control brought back the beam in xy-mode.


Just another case of user stupidity....


best regards,

Andreas


Jokken Feldhaar
 

I wanted to ask if you had applied a signal to both channels when switching to XY-mode. The CRT gets damaged VERY easily by too high brightness, and nothing is more dangerous to a scope than XY-mode without signal. I even have a Hameg in the Job that has 2 blind spots in the phosphor. As the number of electrons the PMT can emit per location is limited, you would get a permanently dark spot very fast.

Regards, Jochen DH6FAZ (I have one 2467 here, and love it!)

Am 21.01.2014 17:00, schrieb andreas.ragner@...:

Hi,

today I found the fix. It seems the 2467 is disabling the
MicroChannelPlate-electrode for intensity amplification in xy-mode. I
guess this is implemented for longer CRT health. Therefore the beam is
much, much darker than in normal timebase settings. Massive ramping up
the intensity control brought back the beam in xy-mode.


Just another case of user stupidity....


best regards,

Andreas


Sscandizzo@...
 

Hi Guys,

Similarly, my 2467B is behaving in the exact same manner: in XY mode flashing the expected waveform briefly, then going blank. Is this, in fact, a form of screen protection. or something else?

Thanks,
Stefan


Chuck Harris
 

X-Y mode should have been disabled in the 2467 MCP scopes, but
it wasn't, so they added a timer circuit board that integrates the
beam current and the sweep speed in some way, and decides when the
beam has to be shut off.

That circuit board is trying to save your scope from damage.

-Chuck Harris

Sscandizzo@... wrote:

Hi Guys,

Similarly, my 2467B is behaving in the exact same manner: in XY mode flashing the expected waveform briefly, then going blank. Is this, in fact, a form of screen protection. or something else?

Thanks,
Stefan






Sscandizzo@...
 

Thank you, Chuck. I was going crazy trying to figure out why the screen blanked quickly after showing the proper image.

-S