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  #1  
Old 03-01-2023, 03:21 PM
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Electronic M Electronic M is offline
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Quote:
Originally Posted by bandersen View Post
I believe they made a 21" Princess model in Brazil. I don't think the 21" head will fit on a Princess cabinet. The CRT also has different specs.
ISTR someone on that predicta Facebook group you're part of sticking a debutante head onto a pedestal cabinet, so the reverse should be possible.
As for CRT compatibility the only difference is heater voltage. A series chassis doesn't even notice that, but a parallel heater chassis like the princess can be adjusted to compensate...In the princess and the similar chassis in the continental console all you have to do to compensate for a different heater voltage is swap the heater hot lead between the 2V tap and the 6V tap on the power transformer.

I've ran 17" headshells as test jigs for 21" chassis before so this can be done.
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  #2  
Old 04-13-2023, 07:17 PM
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Quote:
Originally Posted by Electronic M View Post
ISTR someone on that predicta Facebook group you're part of sticking a debutante head onto a pedestal cabinet, so the reverse should be possible.
As for CRT compatibility the only difference is heater voltage. A series chassis doesn't even notice that, but a parallel heater chassis like the princess can be adjusted to compensate...In the princess and the similar chassis in the continental console all you have to do to compensate for a different heater voltage is swap the heater hot lead between the 2V tap and the 6V tap on the power transformer.

I've ran 17" headshells as test jigs for 21" chassis before so this can be done.
I was thinking about putting a Debutante CRT on a Pedestal set some more. The Pedestal uses 600mA series string tube filament while the 17" CRT is 450mA. You could still do it, but you'd need to add a shunt resistor across the CRT filament.
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  #3  
Old 03-01-2023, 12:51 PM
Chris K Chris K is offline
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Oh dear Lord what a mess I've made! I need to not post these things when I'm not fully engaged! This is what I bought. It does have a 21 inch 21EAP4

Philco Predicta TV Holiday In Mahogany G4242

I'm just looking for a straight substitute but I have heard the cathode emissions on these prematurely fail. So Bob, you're saying a 21FDP4 or equivalent would be the best way to go???
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  #4  
Old 03-01-2023, 12:53 PM
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Never underestimate the power of kludge!
In the HS electronics lab, I bodged a 21 inch screen onto a 19 inch RCA tv using some old 2x4s I found laying around, it was literally an open chassis stuck on to the back of a frame holding the picture tube, but it worked!
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  #5  
Old 03-01-2023, 02:32 PM
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LOL! :P

I'm starting to remember that crazy set now, it was a insane mishmash of what ever I found laying around, 21 inch BW, with a RCA chassis, it sat on my dresser, but I could control it from my bed, as I took the remote control servo motors from another dead set I found and tacked them to volume (on/off) brightness, tint & channel controls and had a long multi wire run to my bedside with all the buttons for it, it was truly a Rube Goldberg machine!

I used it until I was able to find my first color set.
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  #6  
Old 03-01-2023, 03:49 PM
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Running the 2.35 volt filament using the 2.68 volt tap would be fine. I was thinking more about all the other stuff like the yoke impedance and connector pinouts.
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