Pilot tv crt

[Yamamaya42]

So the fact you got a 12AX7 to work at all, can be attributed to sheer luck, as in V1,V2,V3, it's beyond the design limitations that it's being put in, and thus not reliable, only way to go is with 12AT7s, as was intended when it was designed.

[timmy]

The only difference is the gain 12at7 is 70 and 12ax7 is 100 don’t know why they wouldn’t work otherwise.

[Yamamaya42]

Read the data sheets posted... The 2 are not compatible in RF applications, 12AX7 is an high fidelity audio amp, and 12AT7 is a radio frequency amp/osc/mixer, meaning the 12AT7 can work a much higher ranges than the X7 can, the more gain is not relevant.

[timmy]

Originally Posted by Yamamaya42

Read the data sheets posted... The 2 are not compatible in RF applications, 12AX7 is an high fidelity audio amp, and 12AT7 is a radio frequency amp/osc/mixer, meaning the 12AT7 can work a much higher ranges than the X7 can, the more gain is not relevant.

Ok I got it.

[timmy]

First picture from the pilot 37 using the d5-100 crt.

[Electronic M]

At RF frequency minute differences in interelectrode capacitance can kill oscillation and or detune the circuit beyond adjustment range.

[timmy]

Originally Posted by Electronic M

At RF frequency minute differences in interelectrode capacitance can kill oscillation and or detune the circuit beyond adjustment range.

Probably so but I didn’t think I would even get this far with this little crt after all there are no more b&w electrostatic tubes around anymore except the green ones. I’m going to get 3 12at7 and start fresh.

[timmy]

Heres another picture going to need a magnifier just like the original had a magnifier still working to get it better but my cell phone camera don’t take good pics.

[timmy]

Getting there probably the only pilot with a 1.5 inch electrostatic crt it’s small and so was the original tube had to watch it up close and this one too and I have a small magnifying glass but don’t know if I will use it yet. As for the chassis the only thing that was changed is the hv was lowered alittle bit nothing else any changes , were made to the tube itself 2 1 meg resistors and a 500k resistor and a jumper on 2 pins.

[timmy]

Finally got it together and have a magnifier on the back side of the mask little small but it’s b&w not green and can actually watch it.