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Old November 1st 07, 03:53 AM posted to rec.radio.amateur.boatanchors
Bryan Bryan is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 199
Default Yaesu FRG-7 main dial lamp?

Bill KC0IZI wrote:

Does anyone know the specs for a replacement of the pilot lamps
behind the main tuning dial?

The original Yaesu part number was: BQ154-33811A.
One source said is was 12V. 100ma. Is this correct?
Both of mine burned out as I flicked the `light' switch
off and on.
The lamps are those `grain of wheat' types . . .
Any help or suggestions on replacement or a source would be
appreciated.

Bill, KC0IZI


Hi Bill,

Hobby shops are good places to shop for grain of wheat lamps (typically
available in 6V and 12V types). Two issues with using 12V lamps:
a) your AC power supply or automotive charging system supplies 13.8V but the
lamp is rated for only 12V... running current will be high (lifetime will be
significantly shortened).
b) the inrush current (often several times the running current) is quite
high, even if you regulate the voltage. The lifetime is again shortened.
You can use a *current* regulator, set to some value less than the lamp's
current at its design voltage. For currents less than 100mA, the LM317L
would be an excellent choice and is super easy to implement.

Colin (K7FM) suggested replacing the incandescent lamps with LEDs but
mentioned the dispersion angle would be very narrow (creating a spot of
light). A friend who runs a service shop for commercial sound gear tipped
me off... grind/file/sand the lens of the LED. The LED will now have a very
wide dispersion angle.

73,
Bryan WA7PRC