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-   -   Pilot tv crt (http://www.videokarma.org/showthread.php?t=275830)

timmy 05-03-2023 10:01 AM

Pilot tv crt
 
Ok thinking of getting back into getting a d5-100 b@w electrostatic crt to work in a pilot tv. The hv is compatible the heater voltage is .55v I got that covered but the deflection voltages are different the pilot voltages are well over 100 v but the d5-100 are 30 40v otherwise I think it will work but can these voltages be reduced by means of resistors at the crt pin connection points. Can this actually work if this is the only obstacle. The green tube just don’t cut it.

Chris K 05-03-2023 12:27 PM

Yeah Tim I got a NOS green tube for mine and it’s an unsatisfactory compromise. I jumped on a NOS 3KP4 on eBay and paid $300 for it but was refunded when the seller discovered the box was new but the tube was spent. Someone probably got a new tube for their 37, replaced it and put the old one in the box the new one came in. Needless to say I was pretty disappointed ��.

timmy 05-03-2023 12:38 PM

Quote:

Originally Posted by Chris K (Post 3250698)
Yeah Tim I got a NOS green tube for mine and it’s an unsatisfactory compromise. I jumped on a NOS 3KP4 on eBay and paid $300 for it but was refunded when the seller discovered the box was new but the tube was spent. Someone probably got a new tube for their 37, replaced it and put the old one in the box the new one came in. Needless to say I was pretty disappointed ��.

Oh yeah that is disappointing but the green not good hard on the eyes. Lol

Yamamaya42 05-03-2023 12:48 PM

Quote:

Originally Posted by timmy (Post 3250700)
Oh yeah that is disappointing but the green not good hard on the eyes. Lol

Can't resist! :D

https://www.youtube.com/watch?v=rRZ-IxZ46ng

timmy 05-03-2023 12:54 PM

lMFAO

timmy 05-05-2023 07:54 AM

Does anyone know what 5847 tube is weather a 12ax7 or maybe a 12at7 don’t know what this equals.

Zenith26kc20 05-05-2023 08:10 AM

5847 is a pentode. A 12AX7 is a dual triode.

Yamamaya42 05-05-2023 08:39 AM

12AX7 – High-Mu Twin Triode - generally used as audio pre-amp, very versatile.
12AT7 – Also a Mu Twin Triode, but intended for radio frequency amps, mixers & oscillators.
5847 – Pentode used mostly in IF amps

https://frank.pocnet.net/sheets/077/5/5847.pdf
https://frank.pocnet.net/sheets/049/1/12AX7A.pdf
https://frank.pocnet.net/sheets/093/1/12AT7.pdf

timmy 05-05-2023 08:55 AM

Quote:

Originally Posted by Yamamaya42 (Post 3250756)
12AX7 – High-Mu Twin Triode - generally used as audio pre-amp, very versatile.
12AT7 – Also a Mu Twin Triode, but intended for radio frequency amps, mixers & oscillators.
5847 – Pentode used mostly in IF amps

https://frank.pocnet.net/sheets/077/5/5847.pdf
https://frank.pocnet.net/sheets/049/1/12AX7A.pdf
https://frank.pocnet.net/sheets/093/1/12AT7.pdf

So are you saying this tube is a 12at7 because I don’t have the book that shows the 4 digit tube numbers camparing to an actual tube number that I can relate to.

N2IXK 05-05-2023 09:22 AM

The 5847 is a commercial version of the Western Electric 404A pentode.

12AX7 and 12AT7 are dual triodes.

Yamamaya42 05-05-2023 09:26 AM

Depends on the application and how it's used in the circuit, 12AT7,12AU7,12AX7, etc, all have the same 9A basing, and will SORT OF work if you mix them up, but in reality, each type was built to work in a specific type of circuit, so it's best to be sure you have the right one in the right area.

timmy 05-05-2023 09:59 AM

I already found out in this pilot that 5847 works for the antenna amp but not rf amp or oscillator.

timmy 05-05-2023 10:01 AM

What don’t make sense to me is 2 12ax7 test perfect but only one works. And I got a decent b@w picture on the pilot with the d5-100 crt but there is some biasing going on leaving the focus voltage alittle short.

Yamamaya42 05-05-2023 10:22 AM

You never said which pilot you had, but from what I can see, the tuner tubes MUST be 12AT7s.
Any else won't work well.
https://www.earlytelevision.org/pdf/...sams_62-16.pdf

timmy 05-05-2023 10:29 AM

Quote:

Originally Posted by Yamamaya42 (Post 3250763)
You never said which pilot you had, but from what I can see, the tuner tubes MUST be 12AT7s.
Any else won't work well.
https://www.earlytelevision.org/pdf/...sams_62-16.pdf

The pilot is the 37


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