I have some used Metcal gear including the Net Power Meter (NPM-50) and
the MX-500P. When I connect the NPM in line with either of two
handpieces, it shows power levels between 5 and 7 watts. I have not
seen it go higher or lower.

Question: is the power supply output low or is the meter faulty ?

While it is possible to solder with a handpiece, I am not overwhelmed
with the ability to deliver soldering heat. I would guess it higher
than 10W but not 40W. This suggests that the NPM-50 is in error.

The MX-500 power supply draws 40-50 watts from the AC line (using an AC
wattmeter between the power suply and the wall socket). The power
consumption does not seem to be related to what the tip is doing. I.e.
AC input power does not obviously go down when the iron is idling and
up when it is heating the work. This suggests that the MX-500 is not up
to snuff.

If the MX-500 could only put out, say 7W, then the iron would be
getting some power but it would fit with most all the symptoms. What
can I measure to know what's up ? Are there some common points of
failure on either the MX-500 or the NPM-50 that I should look at ?

George

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