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 Post subject: NRI-69 tube tester: which settings to use for UX-120 tube?
PostPosted: Sep Tue 21, 2021 7:03 am 
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Joined: Jul Thu 08, 2021 8:50 pm
Posts: 6
I have NRI-69 tester and I need to test UX-120 tube for Radiola-20. However, I don't see UX-120 tube in the tube chart for NRI-69 (attached). UX-199 (also from Radiola-20) is listed as "99" on the last page of the chart, but I see no UX-120 there. There is "20" in the chart, but it says filament voltage 6.3V, so it must be some other type, not UX-120.
Btw, the chart instructs to switch to 2.5V for "99" filament, but the tester actually gives 3.1V on this setting, which is correct for X-99. Why would they call that setting 2.5, if it is actually 3V ?


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NRI 69 - Operating Instructions and tube chart.pdf [721.61 KiB]
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 Post subject: Re: NRI-69 tube tester: which settings to use for UX-120 tub
PostPosted: Sep Sat 25, 2021 4:13 am 
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Joined: Jul Fri 18, 2008 10:02 am
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Location: near ST Louis Mo 62002
Test it as a 99 , it is and output version of the 99 .

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 Post subject: Re: NRI-69 tube tester: which settings to use for UX-120 tub
PostPosted: Sep Sun 26, 2021 2:14 pm 
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Joined: Jul Thu 08, 2021 8:50 pm
Posts: 6
Quote:
Test it as a 99 , it is and output version of the 99 .


Thank you, Mark.
Should I increase plate voltage when testing UX120? According to the attached chart, X99/UX199 has plate voltage 22-45V, but UX120 has 135V ?
Is plate voltage regulated by Load parameter in the tube tester?
For some reason, NRI-69 tube chart (attached) says Load 65 for X99 tube, why not 45 as in the other chart?


Attachments:
X-99_data_chart.jpg
X-99_data_chart.jpg [ 310.38 KiB | Viewed 158 times ]
X99_in_NRI-69_chart.jpg
X99_in_NRI-69_chart.jpg [ 65.96 KiB | Viewed 158 times ]
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 Post subject: Re: NRI-69 tube tester: which settings to use for UX-120 tub
PostPosted: Sep Sun 26, 2021 3:38 pm 
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Location: S. Dartmouth MA 02748-1225 USA
ymg200 wrote:
Quote:
Test it as a 99, it is and output version of the 99.
Thank you, Mark.
Should I increase plate voltage when testing UX120? According to the attached chart, X99/UX199 has plate voltage 22-45V, but UX120 has 135V? Is plate voltage regulated by Load parameter in the tube tester? For some reason, NRI-69 tube chart .. says Load 65 for X99 tube, why not 45 as in the other chart?


http://www.nostalgiaair.org/References/ ... lash08.htm

If the plate current is too excessive the thorium will be stripped from the filament. If the filament voltage is too high same process... rejuvenation may not return the tube to operation if the tube has a lot of hours, no thorium left internally.

A plate current tester is a better quick tester for thoriated tubes of the 20's because emission is dependent on the filament rheostat. Fixing the filament voltage then measure the amount of current that can pass for the specified plate voltage.

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