I am not an expert...just sharing and documenting my learning journey. Note: You see that the Heater voltage is not a sine wave but more like a pulse. Also, the Heater Voltage is supposed to be 6.3v; running it too low will cause cathode poisoning and too high will shorten life of cathodes. Even with my scope's high bandwidth true rms capability, it is likely not getting a 100% accurate reading.
From watching too much Shango066 I know the thing you talk about at 13:50 is called a brightener. It's basically a small step up transformer to increase the heater voltage.
For the white balance (gray scale tracking), the g07 manual says to turn off input signals or disconnect. However, I agree that a white screen would be useful during the voltage measurement. Eg. measuring cutoff voltage with dark screen vs with white screen.
Because on this monitor, the heater voltage is produced with a separate winding on the secondary side of the flyback. And the flyback runs with the horizontal frequency (its primary is pulse driven by the horizontal output transistor). Other monitor designs produce the heater voltage by other means, for example, the 12inch screens of the CBM PET just use a resistor dropper to generate the heater voltage from the regulated 18V b+ Voltage. So its actual dc there. Other Monitor designs may generate the auxilliary voltages with a separate line transformer running at line frequency.
Turn them clockwise until a bit of their color shows and you achieve grey image. IIRC you are decreasing the negative bias. Ultimately you want the level of beam cutoff across all 3 guns to be equal.
Yes, it is basically saying set your screen (G2) to minimum to see a color for the cutoff setting/grey scale adjustment process. After you adjust everything and apply a video signal, you will still likely need to turn g2 down a bit more to get the perfect blacks. In this earlier video, I walk through the same process. ua-cam.com/video/KE2UAvd3sw0/v-deo.html
@@chriz74 It is in the first step when adjusting the screen control and there is a slightly green screen (the strongest gun and therefore first to present color). Edge of visibility means you see just start to see an image/color on screen. If it was completely dark you could not achieve "Grey" image.
I am not an expert...just sharing and documenting my learning journey. Note: You see that the Heater voltage is not a sine wave but more like a pulse. Also, the Heater Voltage is supposed to be 6.3v; running it too low will cause cathode poisoning and too high will shorten life of cathodes. Even with my scope's high bandwidth true rms capability, it is likely not getting a 100% accurate reading.
From watching too much Shango066 I know the thing you talk about at 13:50 is called a brightener. It's basically a small step up transformer to increase the heater voltage.
Thanks! I couldn't think of the name while filming.
I think you may want to be displaying a white screen while doing these sort of adjustments.
For the white balance (gray scale tracking), the g07 manual says to turn off input signals or disconnect. However, I agree that a white screen would be useful during the voltage measurement. Eg. measuring cutoff voltage with dark screen vs with white screen.
amazing
Any reasons why the heater frequency is measuring 15.7Khz and not at 60hz?
My closest explanation is the flyback primary is fed from the horizontal ckt.
Because on this monitor, the heater voltage is produced with a separate winding on the secondary side of the flyback. And the flyback runs with the horizontal frequency (its primary is pulse driven by the horizontal output transistor). Other monitor designs produce the heater voltage by other means, for example, the 12inch screens of the CBM PET just use a resistor dropper to generate the heater voltage from the regulated 18V b+ Voltage. So its actual dc there. Other Monitor designs may generate the auxilliary voltages with a separate line transformer running at line frequency.
It’s not clear to me what you are doing with those cutoff pots after you get the first blue from rising the G2.
Turn them clockwise until a bit of their color shows and you achieve grey image. IIRC you are decreasing the negative bias. Ultimately you want the level of beam cutoff across all 3 guns to be equal.
@@jacklick the manual though tells to go back to “edge of visibility” once you get a color
Yes, it is basically saying set your screen (G2) to minimum to see a color for the cutoff setting/grey scale adjustment process. After you adjust everything and apply a video signal, you will still likely need to turn g2 down a bit more to get the perfect blacks.
In this earlier video, I walk through the same process.
ua-cam.com/video/KE2UAvd3sw0/v-deo.html
@@jacklick Checked the video. I don’t see you going back to edge of visibility. To me that means you go back to black right before a color was shown.
@@chriz74 It is in the first step when adjusting the screen control and there is a slightly green screen (the strongest gun and therefore first to present color). Edge of visibility means you see just start to see an image/color on screen. If it was completely dark you could not achieve "Grey" image.
amazing