HW100 nightmare

[David Goncalves]

If one uses the same equipment and procedure used in the generation of the
resistance table and pictograph in the manual (a simple VTVM was used), it
is not important that the resistor is still in circuit - since nearly all of
those manual resistance measurements are made at tube pins and connecting
points, where many circuits converge, and you are measuring the entire
resistance of that subsection of components. If you follow the resistance
measurement scheme in the manual, you should be able to isolate issues down
to a handful of components, which you can then measure independantly.

However, if you use a DMM to make the measurements as set in the manual, you
are going to find them to be significantly off from what you expect. While
the DMM has a high input resistance, the circuit is different enough to
cause that error; I'd have to think it is due to the different currents and
voltages the ohmmeter circuit provides to the capacitors and diodes you
inevitably end up measuring across. I started work on my HW-101 with a good
Fluke DMM, but soon had to buy a VTVM because it was getting to be too much
work to interpret the results. Things went easier after that.

However, in the end, I just went ahead and replaced every single resistor
and doide in the rig.
Works great now! :-)

David Goncalves
W1EUJ

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