The OEM incandescent lamp in a Daiwa SWR & Power meter which failed is being replaced with modern LEDs.
Five Philips heads screws, 2 on each side and one at the top are removed, and the meter’s top cover is removed.
The meter is held in place with two tabs on the left side, and a single screw & large washer on the right hand side.
Remove the screw & washer, and the meter is easily removed.
Temporarily unplugging the two connectors will make this easier.
The blue glow was obtained by a thin blue plastic cover over the OEM axial lamp.
This lamp is de-soldered and removed.
LEDs chosen were 3mm Ultra Bright with a useful 45° illumination angle from Element 14.
Ten of these were AUD$7 inc GST.
Only four LEDs are being fitted – four is plenty bright enough!
These are wired in series.
Note that the two outer LEDs are angled to help spread the light across the meter face.
Only a 100R resistor was wired in series for 25mA of current initially, but the LEDs were too bright, so a 500R trimpot was added to tweak the brightness down.
Small 3mm LEDs will ensure the LEDs do not protrude beyond the solder tags, and therefore fit once the meter cover is refitted.
The wiper of the trimpot is soldered directly to the center pin (+13.8V) of the DC coaxial connector.
One side of the trimpot is soldered to the red wire, which goes to the 100R resistor soldered to the solder lugs at the bottom of the meter.
This provides a nice crisp and modern look.
I’ve never liked the hard plastic feet, which can scratch the top of your transceiver, so rubber feet were fitted.
See the modification in this video.
