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Hi folks, has anyone had experience with the TV2/U series Percentage meters?
Looking for the FSD current and possibly FSD resistance also......
I know the TV2BU Percentage meter is 100uA FSD, (never bothered to check the resistance) because I own a mint example. However a TV2/U came my way that I couldn't refuse....
Could be 1mA deflection, something tells me this is possible because most the other meters are 1mA and stayed that way through to the B/U series....
Thanks for any help.
Should be printed somewhere on the meter face itself in small printing. Look on lower edge of scale on the right.
Doc
Doc
Thanks for the reply, but these marion meters are scarce on information unlike the phaostron meters, ect. here is a pic. I found another TV2 U that had a 100uA meter like the B/U and C/U however there could be a difference in series resistors or something because the manual indicates non-compatibility
An externally hosted image should be here but it was not working when we last tested it.
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Okay, how to proceed: Use Ohms law. I know you are looking at your delicate true D'arsonval jeweled movement and wincing in fear over wrapping the needle around the stop pin 26 times, but ohms law really does work. 1 volt in series with a 1 megom resistor will only allow one microamp to flow. Start conservative and work up. First a meg, then 100k, then 10k. The meter movement itself will offer negligable resistance. The resistor that allows full scale deflection will tell you what current the movement takes. Don't have a precision 1 volt source? Put a 100 k pot across a 3v lithium cell and set the wiper for 1v with your DVM. Then feed that through the series resistor through the movement. You will be amazed at how well ohms law really works.
Doc
In series with 1 volt:
1 meg 1 microamp
100k 10 microamp
10k 100 microamp
1k 1 milliamp
Doc
In series with 1 volt:
1 meg 1 microamp
100k 10 microamp
10k 100 microamp
1k 1 milliamp
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Always good advice, thanks for the information. However I was hoping for resistance and/or FSD figures because the coil is open circuit. I'll probably work off the idea that it FSD at 100uA like my TV2B/U, although like I posted before the TM 11-6625-316-34p replacement parts specifies the same meter for the U and AU however a different meter for the BU and CU, which leads me to believe it has a different series calibration resistor in the meter (like the TV7). Who knows. I was thinking of getting a known value tube tested in my BU and then tweaking a pot in series with the U replacement 100uA meter to get an approximate comparison.....only because I REALLY hesitate to dismantle the B/U meter when it's in perfect working order 😉
The 2/U resistor 1 is 250 ohm's on the A/U, B/U and C/U resistor 1 is 300 ohms. From the book that's the only differences in the units. I've had my head stuck in my B/U for a month now and have it tweeked just right. Do not believe all of the resistor mounting board test diagram values, (they must have been pulling an all nighter). I've found that the chassis resistance and voltage diagram values to be true.
Jonathan
Jonathan
Thanks Jonathan, does that mean the resistor is external to the meter?, The funny thing is the book says the TV2U and AU can utilize the same meter, and the BU CU can use another meter and they are not interchangeable even though they both FSD at 100uA. I guess the only way to figure this out is by measuring the FSD resistance of the U meter and another B meter. A volt meter and a 1.5 V cell in series with a trimmer would do nicely......
Percent Quality meter is expensive.
The Percent Quality meters are same for all TV-2 models. It's 100uA full scale (FS) and exact 250 ohms internal resistance. Beside to the FS, the internal resistance of the meter is critical to the accuracy of the tester. The meter is very hard to find, I have been looking for it for a year and current found a source on eBay. The seller is from Korea, he is asking dor $370!
Does anybody has other solution instead of finding the original meter?
Thank you.
The Percent Quality meters are same for all TV-2 models. It's 100uA full scale (FS) and exact 250 ohms internal resistance. Beside to the FS, the internal resistance of the meter is critical to the accuracy of the tester. The meter is very hard to find, I have been looking for it for a year and current found a source on eBay. The seller is from Korea, he is asking dor $370!
Does anybody has other solution instead of finding the original meter?
Thank you.
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