Guide to replacing Signal meter bulbs with LED's

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Admiral
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Admiral »

PLL02A wrote:
Admiral wrote:The only issue I've found is that with older HF kit, whilst the dimmer made a big difference on the old lamp installation, with replacement LEDs the dimmer button is virtually useless as there is no noticeable change in brightness.
Well you could muck about and switch in different values of resistors, But far as i'm concerned a dimmer function on a radio is pretty useless anyhow.
Absolutely agreed, just saying as this is a sticky and could be here for the next 300 years. If you have an older set next to your bed, the old fashioned dimmer that drops from 12v to 8v will work a treat with the old rice grain lamps, but an LED will pump out virtually as much light with the same +vcc drop.
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Buick Mackane
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Buick Mackane »

Mudslinger wrote:You don't have to diffuse them, I have found it makes very little difference.

Iv'e never used an undiffused LED, So i cant make any comparisons, Only going by what iv'e read online, I just fitted one in my tiger that i diffused with sandpaper, And although one side is slightly brighter than the other its a vast improvement over the old filament bulb, It was that dim it almost went out when i keyed up.

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Re: Guide to replacing Signal meter bulbs with LED's

Post by 26CT1862 »

Mudslinger wrote:You don't have to diffuse them, I have found it makes very little difference.

It's positioning that matters more. Don't point the LED at the front of the meter... point it up, and let the reflected light diffuse around the meter housing. It's also not as stupidly bright if you do this.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by k40 »

PLL02A wrote:
Mudslinger wrote:You don't have to diffuse them, I have found it makes very little difference.

Iv'e never used an undiffused LED, So i cant make any comparisons, Only going by what iv'e read online, I just fitted one in my tiger that i diffused with sandpaper, And although one side is slightly brighter than the other its a vast improvement over the old filament bulb, It was that dim it almost went out when i keyed up.

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Re: Guide to replacing Signal meter bulbs with LED's

Post by Tim »

You'll soon get sick of it and put in a proper bulb, you'll then see what the meter is doing once again.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by theEarwigger »

A last thought from me -
As most radios have 12v supply it's better to put 3 LEDs in series to help efficiency. 3 of them also helps diffuse bright spots.
The 5mm LED format has been left far behind now in efficiency terms.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Tim »

Don't like these LED's in a signal meter, almost like looking directly at the sun.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Mudslinger »

Tim wrote:Don't like these LED's in a signal meter, almost like looking directly at the sun.

I bet you couldn't tell the difference if its done correctly with a warm white LED.

The one above only looks bright because the radio was in a relatively dark setting when the picture was taken and the flash wasn't being used.

It is a trick of the camera.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Tim »

Sorry but still don't like them. :thumbdown:
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Re: Guide to replacing Signal meter bulbs with LED's

Post by johnkyrle »

For posterity and for the benefit of our future users of Legacy radio's,go easy with the L.E.D's.Save money in the house on electricity but on a classic rig?NOOOOOOOOO!!!!!!!!!
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Irishman1127 »

Leds forever. Especially blue ones
BLUE LED'S ARE BEST!!!!
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Re: Guide to replacing Signal meter bulbs with LED's

Post by 26mb04 »

Well this is a controversial issue! I like the warm effect of traditional bulbs lamps in older rigs, but they will need replacing continually. This doesn't bode well for the plastic meter housing, which will eventually break after a few replacement operations. I'm not a fan of overly bright LEDs, but if an LED solution will mean I don't have to risk destroying the meter case again in 10 years I'll probably risk an LED. They also have the advantage of keeping most of the heat outside the meter, which might reduce the rate at which the plastic degrades.
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Re: Guide to replacing Signal meter bulbs with LED's

Post by cb4ever104 »

26mb04 wrote: 07 Apr 2021, 23:47 but they will need replacing continually
I disagree . I have radios that are 40 years old that still have the original bulb . I don't like the looks of leds in "my" radios . But hey . Everyone to their own .

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Re: Guide to replacing Signal meter bulbs with LED's

Post by lbcomms »

It depends on the environment the radio is used it to an extent, we always replace with LED in a radio used in a truck or off road / 4WD / diesel camper type vehicles. For base station usage where vibration is minimal I ask the owners what they prefer - a 6V bulb with a dropping resistor (this limits the cold inrush current compared to a 12V bulb wired directly) can last for decades.

We use "0603" wide angle SMT LEDs (designed for LCD backlighting applications) - these give a nice even light.

Installation in a Uniden / Cobra mobile type meter:


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Old bulb and rubber holder removed


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Perfboard cut to fit into the back of the meter housing


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7 x LEDs (0603 SMT, white, 140 degree angle) placed onto board


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Soldered in place with 4 x 2K2 1206 resistors in parallel.
Wires added, + to resistors, - to LED cathodes.


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OPI matte white nail polish is used to cover the board completely except for the LED faces


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Board tested and polish dried before fitting to the meter


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Board in place, secured with some epoxy resin at each end


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Final result - completely uniform brightness left to right
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Re: Guide to replacing Signal meter bulbs with LED's

Post by Stronty »

That is a thing of beauty, thanks for sharing @lbcomms
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