Neon Lamps In Vintage Radio

  • Thread starter the1930s@googlemail.com
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the1930s@googlemail.com

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Hi, not sure if this is the right place to ask, but here goes.. I have
an old 1960's radio that uses two 6 volt incandescent lamps for the
dial. Would it be possible to substitute these for NE-2 neon bulbs?
The side contact on the bulbs connect to the chassis of the radio
which acts as earth.
 
the1930s@googlemail.com wrote:

Hi, not sure if this is the right place to ask, but here goes.. I have
an old 1960's radio that uses two 6 volt incandescent lamps for the
dial. Would it be possible to substitute these for NE-2 neon bulbs?
Click to expand...
Yes! However you would need to disconnect the 6 volt supply and then
provide suitable dropper resistors from the HT for the neons.

The side contact on the bulbs connect to the chassis of the radio
which acts as earth.
Click to expand...
I can't for the life of me understand why you should want to do this.
The 6v bulbs are available and cheap enough.

--
Best Regards:
Baron.
 
I want long life bulbs in the radio as it's hard opening the radio to
replace the bulbs. I could go with LED's if that's easier.
 
I forgot to mention that this is a transistor radio, the only high
voltage is at the transformer. Perhaps LED's are the easy way. Some
bright orange ones would do. What resistors would I need for them?
 
<the1930s@googlemail.com>

I want long life bulbs in the radio as it's hard opening the radio to
replace the bulbs.
Click to expand...

** Use 9 or 12 volt bulbs - you goose.

Last for a decade, or more.

NE-2s will never produce enough light.




....... Phil
 
** Use 9 or 12 volt bulbs - you goose.
Click to expand...
I thought of that, however as the existing pilot lamps are hidden
behind the dial and reflect off the clear faceplate, they aren't
bright enough now, so 12 volt bulbs would be ineffective. I'm
thinking of going with bright LED's and bringing them around the front
of the dial for more light.
 
<the1930s@googlemail.com>

I forgot to mention that this is a transistor radio,
Click to expand...

** LOL - wot a wacker.


the only high
voltage is at the transformer. Perhaps LED's are the easy way. Some
bright orange ones would do. What resistors would I need for them?
Click to expand...

** Vintage ones.




....... Phil
 
the1930s@googlemail.com wrote:

I forgot to mention that this is a transistor radio, the only high
voltage is at the transformer. Perhaps LED's are the easy way. Some
bright orange ones would do. What resistors would I need for them?
Click to expand...
In which case I would definitely stay with the incandescent bulbs!

--
Best Regards:
Baron.
 
On Nov 3, 8:58 am, "the19...@googlemail.com" <the19...@googlemail.com>
wrote:
I forgot to mention that this is a transistor radio, the only high
voltage is at the transformer. Perhaps LED's are the easy way. Some
bright orange ones would do. What resistors would I need for them?
Click to expand...
Hi, The1930s. A bit of a problem here -- older transistor radios used
the low voltage AC secondary for the lamps, not DC. That means you'll
have to drive your LEDs with a series diode, too.

I'm assuming you've got a 6.3VAC secondary which is driving the
lamps. Orange LEDs require around 2V forward voltage drop when on.
If you add a 1N4001 diode in series, you might want to start with a
220 ohm, 1/4 watt resistor. The end product will be the resistor and
the diode in series with the LED.

Good luck
Chris
 
The radio does work without the lamps. I think I will go with LED's.
I've found a "sunset red" red LED at the Dick Smith Electronics web
site, but I can't check the voltage because the site keeps crashing.
 
Baron (baron.nospam@linuxmainiac.nospam.net) writes:

I can't for the life of me understand why you should want to do this.
The 6v bulbs are available and cheap enough.

Especially since the bulbs are there to luminate the dial, and neon bulbs
Click to expand...
aren't likely to supply the same amount of light. Their place in things
is usually indicators of voltage rather than to supply light.

Michael
 
On Sat, 03 Nov 2007 06:15:36 -0700, "the1930s@googlemail.com"
<the1930s@googlemail.com> wrote:

Hi, not sure if this is the right place to ask, but here goes.. I have
an old 1960's radio that uses two 6 volt incandescent lamps for the
dial. Would it be possible to substitute these for NE-2 neon bulbs?
The side contact on the bulbs connect to the chassis of the radio
which acts as earth.
Click to expand...
Not without some tinkering with circuitry. A 6 volt incandescent
requires 6.3 volts nominal at something like 100-200 milliamps to
light.

A NE2 or similar small neon requires about 60-80 volts or so to ionize
the gas and then the current has to be limited to a few milliamps with
a resistor.

You might substitute an LED with suitable dropping resistor and a
rectifier since most OLD toob type radios used AC for the pilot lamps
- they even make replacement LED lamps with bayonet and screw bases
with built in resistors - for DC.

If you are dead set on neon for esthetic reasons it can be done, but
requires more arm waving and head scratching.

One thing - does the radio work without the lamp bulbs in place? Some
of the old AC/DC radios put the lamps in series with the filament
string of the tubes the lamps would initially come on very bright then
quickly dim to normal as the tubes heated - without the lamps the
radio wouldn't play at all or be very distorted and weak sounding.
--

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On Sat, 03 Nov 2007 07:22:54 -0700, "the1930s@googlemail.com"
<the1930s@googlemail.com> wrote:

The radio does work without the lamps. I think I will go with LED's.
I've found a "sunset red" red LED at the Dick Smith Electronics web
site, but I can't check the voltage because the site keeps crashing.
Click to expand...
Red LEDs require about 1.8 - 2.3 volts to light and most standard
size - 20 milliamps so would require a dropping resistor to limit
current, as well as rectifier - many leds only withstand a 5 volt
reverse voltage before they self destruct.

But check the specs.

When they specify light intensity in millicandellas or mcd that is the
light output in a specific area of the target - the beam width and
intensity have to be considered. The light of an LED is directional -
something to consider when replacing incandescent's with leds.


--

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When they specify light intensity in millicandellas or mcd that is the
light output in a specific area of the target - the beam width and
intensity have to be considered. The light of an LED is directional -
something to consider when replacing incandescent's with leds.
I've been thinking about that, I will check the specs when the
Click to expand...
stupid site lets me. The LED is advertised as super bright, I don't
won't a dim one, there's no point in that.
 
I have some 1N4002 and 1N4007 diodes. Would they work?
 
On Nov 3, 9:49 am, "the19...@googlemail.com" <the19...@googlemail.com>
wrote:
I have some 1N4002 and 1N4007 diodes. Would they work?
Click to expand...
Yes. These diodes will all work for the low voltage of the 6V lamp
socket. A 1N4002 blocks to 100V, a 1N4007 to 1000V. Save the 1N4007s
for higher voltage if you've got both.

I should mention that some radios have the incandescent bulbs in
series, which would mean a 12V secondary. Try pulling one bulb, and
seeing if the other goes out. If so, you may have a 12VAC secondary.

As above, a 220 ohm, 1/4W resistor in series with the LED and the
1N400X diode should work fine if there's a 6VAC secondary. If it's a
12VAC secondary with the bulbs in series, then make sure to replace
both incandescents with LEDs, or it won't work. Also be sure all the
LEDs and diodes are lined up so the anodes are toward the more
positive side, or it'll be a frustrating experience.

When you're at the website, look for the "viewing angle" to see if the
LED light is tightly focused. You probably want a wide angle LED
here.

Good luck
Chris
 
I' going to have to stay with the existing lamps. I inspecting the
radio and there's no way the LED's will fit between the faceplate and
the dial, without filing a hole in the faceplate, and I don't want to
do that. Thanks for all your help.
 
In article <1194099292.550986.43460@y42g2000hsy.googlegroups.com>,
Chris <cfoley1064@yahoo.com> wrote:

On Nov 3, 8:58 am, "the19...@googlemail.com" <the19...@googlemail.com
wrote:
I forgot to mention that this is a transistor radio, the only high
voltage is at the transformer. Perhaps LED's are the easy way. Some
bright orange ones would do. What resistors would I need for them?

Hi, The1930s. A bit of a problem here -- older transistor radios used
the low voltage AC secondary for the lamps, not DC. That means you'll
have to drive your LEDs with a series diode, too.
Click to expand...
You can simply run two LEDs back-to back. If you have enough voltage,
you can run two strings of two diodes (4 total) back to back with a
smaller resistor, and get more light for the same power. LEDs are
current-sensitive devices - the resistor is there to limit the current,
but the voltage dropped by the LED may vary a bit - ideally, you might
want to measure the actual voltage dropped by the specific part in hand
when adjusted to the correct specified current - use a potentiometer and
a milliammeter, and start with a high resistance on the pot (too little
current is fine, too much current is a one-time magic-smoke-releasing
event. Then stuff in a resistor just a bit larger (for a safety factor)
than the reading on the pot when you have the pot adjusted for the rated
current. If you have 6 volts, you should certainly be able to run 2 red
or yellow LEDs in series.

You might get a better color using a red and a yellow or green. Depends
what color you want...

The ones I presently have in stock list a typical forward voltage at
20mA of 2V and 2.2V, with maximums of 2.5V and 2.6 V - so if you have
6.3V available, pick a resistor to drop ~2V at 20 mA and it should work
to drive 2 in series. ie, 100 ohms, for that example. Your parts may
vary - typical circuits are designed to underdrive the LEDs to keep them
safe with part variations (ie, 270 ohms from 5 volts in series with a
single LED.)

6.3VAC~--------
|
\
/
\ 100, 110, 120 Ohms (progressively dimmer and safer)
/
|
-------
| |
\/ -- Back-to-back LEDs
-- /\
| |
|------| (connection here keeps reverse voltage low)
| |
\/ --
-- /\ Back-to-back LEDs
| |
-------
|
---
-

--
Cats, coffee, chocolate...vices to live by
 
On Sat, 03 Nov 2007 07:41:32 -0700, "the1930s@googlemail.com"
<the1930s@googlemail.com> wrote:

When they specify light intensity in millicandellas or mcd that is the
light output in a specific area of the target - the beam width and
intensity have to be considered. The light of an LED is directional -
something to consider when replacing incandescent's with leds.
I've been thinking about that, I will check the specs when the
stupid site lets me. The LED is advertised as super bright, I don't
won't a dim one, there's no point in that.

Well - there's all kinds of leds today. I have a few in my MC tail
Click to expand...
lamp that are rated in lumens, dissipate a watt each, and have a 120
degree beam spread.

Overkill for a pilot lamp.
--

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On Sat, 03 Nov 2007 07:49:12 -0700, "the1930s@googlemail.com"
<the1930s@googlemail.com> wrote:

I have some 1N4002 and 1N4007 diodes. Would they work?
Sure, with a simple 20 milliamp red led almost anything will work.
Click to expand...

I think the 4002 is a 100 volt part and the 4007 a 600V part and one
amp/1,000 ma.

With only 20 ma, a small signal diode like the 1N914 or 1N4148 will
work. (depending on manufacturer they go from 50-100V and 50-100
milliamps)

You can put two leds back to back so each lights on each half cycle of
the sine wave. Since the duty cycle is only 50% - the current would
be double for the same intensity of light from each - when you
calculate the dropping resistor.

When one led is forward conducting it limits the reverse voltage to
the other - and more light out with two - or you were talking about
replacing two leds in the first place.
--

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