help with LG-1 (IG-42)

[Ron]

Richard Keller wrote:
> In my attempts to align and calibrate the signal generator, I discovered
> that Heath did not provide much help in these old manuals.
>
> It says to adjust the FINE ATTEN for 2VAC and then set the CXR CAL to full
> scale. No presets are mentioned whatsoever. Is the CXR CAL supposed to be
> set to minimum before this adjustment?

Makes no difference. This calibration simply insures that the meter
reads full scale when the output is 2VAC.

> Also, I cannot figure out a way to test the STEP ATTEN as my unit shows no
> linearity between steps (I.E. X10 should be the same as X1 with the decimal
> point moved over 1 position). So what I did was test the steps with an
> ohmmeter, expecting to see graduated changes while going through the steps.
> Not so. Is the STEP ATTEN supposed to have max output at X1 or X10K?

This type of attenuator cannot be tested by simply measuring
resistor values. To measure, first disconnect all 62 ohm
resistors from ground and disconnect the shielded cable. Then
measure across each resistor and replace those that are off
nominal value by more than 5%.

Note that the meter reads the voltage before the attenuator,
so is not affected by the attenuator.

The output signal will be highest when the attenuator is at
its right most position.

-- Ron

>
> Confusing, huh? What say you?
> 73, Dick KF4NS
> St. Petersburg, FL 33714 USA
> Keep the glow!

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