[Ron Ramirez]

You may have read my posting in the 42-761EZ Chassis Restoration thread about how I tried a 120 volt LED as a dial lamp, with less than stellar results.

I not only bought a couple 120 volt LEDs from superbrightleds.com , I also bought two 6 volt, 4 LED miniature bayonet lamps to test in a couple Philco sets of mine.

The results with these were much better.

First, let's look at a 650 chassis with a conventional incandescent 55 lamp behind the dial:

[Image: http://www.philcoradio.com/images/phorum...fe856c.jpg]

Looks fine, like a 650 dial should look, right?

Now, look at it with a 4-LED lamp replacement:

[Image: http://www.philcoradio.com/images/phorum...49a92e.jpg]

Much brighter. With the LED lamp, you can tell this dial scale is a reproduction (made by me).

I had wondered aloud if an LED lamp would cause any noticeable RF interference. So, my next test was to put one of the LED lamps in my 610T that has a restored and working 630 chassis inside.

[Image: http://www.philcoradio.com/images/phorum...b4e499.jpg]

Nice and bright. Since this set has its original dial scale, you really can't tell that the lamp is an LED - you don't see the very bright, cool white light, just a brighter dial.

I connected antenna and ground, and tuned it around on all three bands. It was no noisier than usual - the LED did not add any RF interference to the 630's reception.

So I can give the 4-LED replacement for the 55 lamp two thumbs up!

[BrendaAnnD]

They also have amber lamps (single LED, frosted) that give a nice yellow light, with similar coloration to incandescent in many circumstances. Good coverage (light dispersion), too.

[kporter]

Cool! Ron, is that the 32 or 90 degree beam angle?

[Ron Ramirez]

32 degree on these; superbrightleds.com does not offer the 6V 4-LED lamps in 90 degree.

They are available for much less $ here:
http://www.pinballlife.com/index.php?p=product&id=2561
Plus, Pinball Life offers them in "warm white" as well as "cool white."

The beam angle is not specified for these, however.

32 degree is fine if the lamp is facing the dial. For Philco sets with the lamp at right angles to the dial, you would want a 180 degree LED lamp - and hope that it's bright enough. The 120 volt lamp I used in my 42-761 is a single LED 180 degree bulb, and it isn't bright enough.

[kporter]

Great, thanks!

Kent

[Arran]

I was thinking of trying these in sets with back lit plastic dials that are notorious for the dials developing burn marks. This can happen with some Rogers dials when someone uses a replacement pilot bulb with the wrong length of envelope, the bulbs fit through large grommets trhough the back at an angle. Another set notorious for pilot lamp problems are the Philco 46-1201s, it's very easy to situate the pilot lamp so it touches the back of the plastic screen, but now you can get a C7 LED replacement in Walmart so that isn't a problem.
Regards
Arran

[codefox1]

Would a little NE2 in a dab of whatever do?

[morzh]

Where did that idea that LEDs create radio interference at broadcast frequencies come from?

If you use an LED AND a converter, yes, a switcher is always noisy to a degree, but just an LED by itself.....

[Arran]

I've picked up some interference from the LED counter top puck lights in the kitchen, no so much on the AM broadcast band but on shortwave, but it's not the LEDs causing it so much as the switch mode supplies up in the attic radiating through the wiring. The way that I have them connected is so the switch mode supplies are plugged into an outlet up in the attic that I can switch off from the kitchen, should the need arise to replace the switchers with proper linear supplies, with a mains transformer, it's easy to do. I also had LED Christmas lights going 24 hours a day 7 days a week for about a month and they don't interfere with anything, those are connected a series-parallel arrangement I think.
Regards
Arran

[Eliot Ness]

Interesting findings. The two benefits I hope to see with the 44/47 replacements are greater dial illumination and eliminating burns on those large dials that Arran mentioned earlier.

One possible issue I see is the angle of the bulbs I bought. I'll have to experiment but I suspect they will work best for sets where the bulb is facing the dial, but the lens they use at Pinball Life offers between 170 and 120 degrees of diffusion (concave and flat top).

http://www.pinballlife.com/index.php?p=product&id=1881

I also have some retro's, super brights, and ultra brights in both cool and warm white to experiment with from Coin Taker:

http://shop.cointaker.com/category.sc?categoryId=150

A side benefit mentioned in earlier threads is the smaller current draw of the LED's being a little kinder to our 80 year old transformer windings.

[PhilcoMike]

Ron,

Great info, thanks.

You may want to check your thread link in your first post, different radio.

Mike

[AI2V]

As for LED's causing interference, you are generally safe. It's only when you use the auto-blinking and auto-color changing LED's that you will get considerable RF noise across the full broadcast band; you can detect the noise from several feet away.

The shape of the beam of an LED can be altered by sanding down the rounded point; leaving it course from sanding often works nicely for backlighting a dial.

[Ron Ramirez]

You may want to check your thread link in your first post, different radio.

Acked, and corrected.

[Marsupial]

When I read "fun with LDE lamps" I tough you were playing with red or blue leds... !

I actually gave that a try on my 47-1230, one different color on each side. Makes a cool effect in that the pointer (a bar, really) separate the 2 colors.
However, I really like the natural look of warm incandescent... but on some of those repaint I see every now and then, colored LEDs might be interesting.

The biggest gain I see about using LEDs is longer material life near the lamps. Dials or other tends to age faster when heated.

[awc71]

Great job!

I was lucky in that my 46-1201 uses a C7 which I could easily find an LED bulb for. I got mine on Amazon - it's called the G7. (It's the only C7 LED with 4.5 stars.) While not as warm as an incandescent, it's not as cold as some LED's. It may have been designed to burn at a warmer hue as it is sometimes used in night lights.

My diffuser panel was burned in, so even though the LED is cool, I cut out a piece of a heat resistent diffuser film and swapped it out (I used the sheets used to filter the high powered and HOT lamps used in photo and motion picture lighting).

The diffuser film sheet comes in different shades and textures for different lighting effects so if need be, I was also ready to swap in a more yellow-ish sheet. These are found on http://www.bhphotovideo.com/ in case anyone is interested.