Designing Custom Analog Meter Scales

Below, we show the steps required to design custom scales, and install them in an existing meter.

The meters below were obtained on eBay for $7.50 each. The seller also included some extra scale faces.

As discussed elsewhere, MB-1 can drive any analog meter with a full scale current rating of 1 milliamp or less. The meters faces on these meters showed a full scale value of 500 microamps. We verified that with the procedure described here.

The custom scales used below were designed with Tonne Software's Meter Program. The Tonne website provides a detailed manual for installing custom meter faces. An abbreviated description is given below.  MeterBuilder has no business affiliation with Tonne Software.
 

Steps:

1. The meter cover is removed from the meter by prying from the top. This meter uses a snap-on fit. No glue or tape is used.
    
2. To remove the existing meter face, pop it up on the side away from the needle, and rotate CCW until the plate clears the needle.
    
3. We made a separate meter face for each of the three meters: one for power and SWR, one for RF current, and one to monitor the amplifier exhaust temperature.
    
4. Line up the removed meter face with the new face. The two mounting holes on the bottom serve as convenient reference points. Cut the new face using the metal meter face as a template.
    
5. Double sided tape was used to affix the new meter face. Glue can also be used. Mount the face on the unfinished side of the metal meter face to prevent a shadow from the original scale.
    
6. Replace the new meter face on the meter using the same precautions as when removing it. Replace the meter cover making sure to line up the zeroing screw on the meter cover with the zeroing tab on the meter movement.
    
7. The meters are now ready to be calibrated with the MB-1 Panel Meter calibration feature.

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