EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: proschuno on March 16, 2014, 12:53:22 pm
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So I just obtained a free Triplett 630A multimeter from a guy, and after testing and measuring it it works quite well, especially on the 1.2 mA DC range, it's spot on. However, it tends to be a little off, usually by 3-4%, on the voltage and any currents above 12mA Dc range.
Also, what read 120V AC on two flukes read 100V on the triplett, so I doubt it'll work accurately on high voltages ( which I frequently work with playing with vacuum tubes). The original manual says that it can be precise as 1.5% on all ranges (is this true, or just 'hype'?)
EDIT:
Measuring the internal resistors, many of them have fallen out of spec, they are .5% resistors. I'm supposing this is what's leading to inaccuracies, however all the resistors for the mA range have fallen out of spec, yet they are accurate for the most part (as stated the 1.2 mA range is spot on).
So could there also be something wrong with the dial itself?
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i also am curious. anyone?
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So I just obtained a free Triplett 630A multimeter from a guy, and after testing and measuring it it works quite well, especially on the 1.2 mA DC range, it's spot on. However, it tends to be a little off, usually by 3-4%, on the voltage and any currents above 12mA Dc range.
Also, what read 120V AC on two flukes read 100V on the triplett, so I doubt it'll work accurately on high voltages ( which I frequently work with playing with vacuum tubes). The original manual says that it can be precise as 1.5% on all ranges (is this true, or just 'hype'?)
EDIT:
Measuring the internal resistors, many of them have fallen out of spec, they are .5% resistors. I'm supposing this is what's leading to inaccuracies, however all the resistors for the mA range have fallen out of spec, yet they are accurate for the most part (as stated the 1.2 mA range is spot on).
So could there also be something wrong with the dial itself?
I would swap out the resistors first, and then try again. Also might try some Deoxit on the switches.
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Here is the manual
http://www.triplett.com/wp-content/uploads/2012/11/84-668.pdfWhat (http://www.triplett.com/wp-content/uploads/2012/11/84-668.pdfWhat) ranges is it ogg on, and
What ranges is it off on, and how well is it on resistances?