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Old 07-06-2018, 07:06 AM
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Pilot tv and 2 inch b&w

Ok so I'm at it again I'm thinking of wiring up a d5-100w crt from the Sinclair portable tv to my pilot tv since this may be the only way to get a b&w pic from a pilot these days. I already use one of these tubes in my oscilloscope clock and it's great. It took awhile to get the heater voltage right but it's been going for awhile now with no problems. The challenge will be again to get the heater voltage right. I can't use a regulated 1 volt because 1 volt will be to much so 1 volt from a transformer using resistors should work as this is what I did to use the tube in the clock. 1 volt then the heater load placed on it will drop to .50 volt which is the voltage needed for the tube. With the clock I used a resistor to drop the 6 volts for the heater then use the voltage on a smaller 12 volt transformer secondary then a resistor off the primary to get 1 volt then the load brings it down to .50 volts. Of course I will have to make a mask from the 3 inch round to a 2 inch rectangular. It will be odd
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Old 07-26-2018, 12:02 PM
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Well I got the heater supply right and wired it in to the pilot tv and the 2 inch b&w crt did light up but the picture was somewhat distorted and the screen would not light up unless I removed the g1 from the tube put it on and the screen blacks out so there must be some cutoff or bias problem that makes it not compatible with the pilot or there would have to be a mod to make it work because the g1 is needed because the brightness don't work without it. The voltages for g1 are very different between the small b&w tube and the 3kp4 tube. Higher for the 3kp4 so I tried resistors and caps I got it close but not good enough to view the picture being shown. The focus was good as well as the horiz and verticle drives for the plates as it filled the screen so I was close. Would have been nice to see black and white content coming from the pilot even though it would have been a 2 inch screen.
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Old 07-26-2018, 02:47 PM
dtryon dtryon is offline
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Other Problems

I don't think I quite understand what your doing. Isn't the deflection on an old Sinclair TV magnetic and I believe the pilot used electrostatic. I would think the biggest problem would be the horiz and vert scanning not the heater voltage. How did you solve that problem?

Thanks,
Dennis
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Old 07-26-2018, 03:13 PM
Tom9589 Tom9589 is offline
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The D5-100W CRT used in the Sinclair TV was made by Telefunken and is an electrostatic deflected CRT.
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Old 07-26-2018, 04:38 PM
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Quote:
Originally Posted by dtryon View Post
I don't think I quite understand what your doing. Isn't the deflection on an old Sinclair TV magnetic and I believe the pilot used electrostatic. I would think the biggest problem would be the horiz and vert scanning not the heater voltage. How did you solve that problem?

Thanks,
Dennis
Yes the Sinclair crt is electrostatic not magnetic. The heater voltage was criticle because it was .55 volts that had to be right since I already burned one of these crts out. I used a small center tap 12 volt trans and fed 6 volts to the secondary and with resistors got the voltage down to what I needed from the primary, 1 volt under load gave me just under .50 volts.
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Old 07-26-2018, 04:50 PM
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Just wanted to add that I would still mask the CRT in a smaller "double-D" style. You'll only lose a little bit of the edges of the picture, but it will look a whole lot more convincing. With construction paper it would be easy to make either the early white mask or the later black and gold pinstriped mask. Good luck!
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Old 07-26-2018, 05:30 PM
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Quote:
Originally Posted by decojoe67 View Post
Just wanted to add that I would still mask the CRT in a smaller "double-D" style. You'll only lose a little bit of the edges of the picture, but it will look a whole lot more convincing. With construction paper it would be easy to make either the early white mask or the later black and gold pinstriped mask. Good luck!
Well I had the plans for the mask but I think it's a done deal because I really don't want to change much in the set with the higher cutoff voltages of the pilot and I'm not sure how to modify it simply to get it to work.
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Old 07-26-2018, 06:28 PM
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Quote:
Originally Posted by timmy View Post
Well I had the plans for the mask but I think it's a done deal because I really don't want to change much in the set with the higher cutoff voltages of the pilot and I'm not sure how to modify it simply to get it to work.
I would agree. There's still many of those Pilot TV's around in various states of repair. You might try to nab one with a rough cabinet for a reasonable price and hope the CRT is good. I know someone who haggled for a very nice one at a local antiques shop recently - he got it for $75! - and it turns out with a good CRT! That's about the only way to get the original white CRT these days, or even the green substitute, which is acceptable.
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Old 07-26-2018, 07:51 PM
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Quote:
Originally Posted by decojoe67 View Post
I would agree. There's still many of those Pilot TV's around in various states of repair. You might try to nab one with a rough cabinet for a reasonable price and hope the CRT is good. I know someone who haggled for a very nice one at a local antiques shop recently - he got it for $75! - and it turns out with a good CRT! That's about the only way to get the original white CRT these days, or even the green substitute, which is acceptable.
That is so rare to get a pilot with a good crt but would be nice to find one. I already have a 3kp1 green crt in it and have spares but a white one would be great.
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Old 07-26-2018, 08:09 PM
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John Marinello John Marinello is offline
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What if you put a red filter in front of the 3kp1?
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Old 07-27-2018, 04:39 AM
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What if you put a red filter in front of the 3kp1?
Tried the filter but it's to dark.
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Old 07-27-2018, 10:59 PM
dtryon dtryon is offline
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Didn't know!

Hey guys,
Thanks for letting me know about the electrostatic deflection in the Sinclair TV's. I had no idea they used that at such a late date. Weren't the Sinclair's made in the late 70's? Anyway, thanks again that helps me understand what your trying to do Timmy. When you get it working I hope you give some info on the modifications.

Thanks Guys,

Dennis
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Old 07-27-2018, 11:16 PM
dtryon dtryon is offline
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Other Tubes ?

Guys,
One other thing I would appreciate knowing. Are their any other examples of electrostatic deflection used in more modern TV's ? Maybe other mini TV's or perhaps view finders, etc. ?

Thanks,

Dennis
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