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-   Early B&W and Projection TV (http://www.videokarma.org/forumdisplay.php?f=19)
-   -   Checking hv (http://www.videokarma.org/showthread.php?t=276408)

timmy 02-02-2024 01:55 PM
Quote:
Originally Posted by Yamamaya42 (Post 3255532)
It seems that there are substantial differences between the two that would need to be addressed before it would work well it looks like.

https://tubedata.wernull.com/sheets/168/3/3KP1.pdf
http://www.r-type.org/pdfs/d5-100gh.pdf

Namely in the deflecting plates capacitive loads.
3KP1 seem to be around 8-11 pf, and d5-100 is much lower, .09-3pf? Hard to tell, not in English.
Also the deflecting plates voltages a a bit different, this is no doubt the source of the problem.
Does this the small crt needs more deflection voltage

Yamamaya42 02-02-2024 02:03 PM
Hard to tell, one is listed in volts per inch, the other is per cm, not sure how that crosses over.
But more likely than not, it's the difference in pf that is the issue.

timmy 02-02-2024 02:05 PM
And the pf cannot be made up with the proper cap ?

Yamamaya42 02-02-2024 02:14 PM
That will have to be looked into by someone who knows the circuit a bit more, but I'm sure it can be adjusted.

timmy 02-02-2024 02:15 PM
Is The pf difference with the circuit or the deflection plates themselves

timmy 02-02-2024 02:18 PM
I did manage to get the screen full but the people on the screen part was missing to big stretched

jr_tech 02-02-2024 02:30 PM
Quote:
Originally Posted by timmy (Post 3255533)
Does this the small crt needs more deflection voltage
Yes, since the distance from the center of deflection to the screen is so small in this tiny tube, deflection sensitivity is poor.

jr

Yamamaya42 02-02-2024 02:31 PM
The original set and circuit must have been made with the 3KP4 in mind, and the capacitive load it would put on the circuit, so it makes sense that a different tube would have unexpected results, so as mentioned, someone with a good understanding of this set may be able to help adapt it.
May only need a few changes.

timmy 02-02-2024 02:36 PM
I wonder if the hv deflection caps would make any difference

timmy 02-02-2024 05:37 PM
Maybe a different vertical size pot instead of 5 meg

Yamamaya42 02-02-2024 07:22 PM
Unfortunately, it won't be as easy as a single part, It will take someone with knowledge of tube circuits who can look over the documentation for the set and theory of operation and make suggestions on how to adapt it better to that CRT, it may just be needing a few changes of caps and resistors in the vertical drive / output area to make it a better match.

jr_tech 02-02-2024 10:08 PM
Perhaps it would be useful if the B+/B- voltages applied to the vertical circuit were increased :scratch2:....what do they measure now?

jr

timmy 02-03-2024 06:06 AM
So I have to figure out the b+ voltage to the vertical amp or multi.I’m not certain where the voltage comes from for vertical possibly a tap from focus voltage

jr_tech 02-03-2024 02:55 PM
B+ is from the 25Z6, and B- is from the 35W4...Don’t you have a schematic?
What do they measure now?

jr

timmy 02-03-2024 03:17 PM
Quote:
Originally Posted by jr_tech (Post 3255559)
B+ is from the 25Z6, and B- is from the 35W4...Don’t you have a schematic?
What do they measure now?

jr
Yes I know where to get the b+ but I thought you meant the b+ to the vertical circuit I’ll check the voltage at the rec tubes I do know it’s close to what it should be. And yes I have a schematic. How would I be able to up the b+ ?


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