Pro-43 / Old RS Scanner Backlight Replacement

[PHOENIX_SCANNER]

Has anyone had the backlight go out on one of these old RS scanners, and has anyone been successful in replacing one. If so, please explain.

Thanks.

 

[rooivalk]

What's the voltage to the bulb? I bet an LED could replace it, though I've never tried, nor do I know if it's easily accessible.

 

[PHOENIX_SCANNER]

That's an interesting thought? I'm gonna have to find out now.

 

[ka2wey]

Pro-43 backlight problem

The LCD backlight lamp is a 6 volt 35ma microsize lamp. However don't assume that lamp is bad, the
circuitry that supplies the voltage to light the lamp may be defective. Check for lamp voltage and and do a
lamp continuity check first.

 

[MarkWestin]

I did put a white LED in my PRO-43 about 10 years ago. I can't really remember but I probably used a 270 ohm resistor, since I was using the same combination on my model trains at the time. If the LED was too bright for your taste, you could experiment with resistor values up to about 500 ohms. If your backlight is currently working I don't recommend replacing it with a LED. The light bulb is mounted above the LCD and just shines down on the front of it. My LED shines down on the LCD in a relatively narrow pattern and only lights up about the center third of the display. I can't see any way to light the display from the back without major modifications.

Mark

 

[PHOENIX_SCANNER]

The LCD backlight lamp is a 6 volt 35ma microsize lamp. However don't assume that lamp is bad, the
circuitry that supplies the voltage to light the lamp may be defective. Check for lamp voltage and and do a
lamp continuity check first.

Good points. I had even considered that my (dying) keypad might be the issue (trying to find a replacement).

I will be sure to check. Should be interesting trying to find that bulb lol.

Mark, sounds like I might want to stick with the bulb if it just catches part of the display. Those bulbs never were the best lighting anyway.... My Pro-39 light was always weak, especially with nicad batteries (lower voltage).

I'm going to do the keypad as soon as I can find one, and once I have it apart we shall see what comes next. It's such a fine little radio I don't mind working on it.

 

[slicerwizard]

It's fairly easy to replace the existing bulb with three green or orange LEDs wired in series (plus a current limiting resistor of course). If spaced appropriately, they illuminate the entire display.