[RickC]

I am new to Radio restorations, so please excuse me if I make an error.

I am posting the following to help others, and myself, to find the correct bulb replacement for the Philco 15DX.

The Radio Service Data Sheet shows the following:

Pilot Light V12
Pilot Light (Shadow Tuning) V13
Cabinet Light V14

On the bottom right of the Radio Service Data Sheet is the following:

…V12, V13, V14, 6.3 V

The Replacement Parts Model 15 Series shows:

Pilot Light 6008
Pilot Light (Shadow Tuning) 6008
Cabinet Light 6600

The Philco Parts Catalog 1936 shows:

6608 6-8 volts 250 ma Blue bead color Type D (looks like a sewing machine bulb)
6600 Not Listed

The Philco Library shows:

6608 Equivalent No. is 46

Page one of this Thread talks about the Cabinet Light bulb having an E17 base and the bulb is possible shaped like a sewing machine bulb. 
The (replacement) Cabinet Light bulb presently in my radio appears to have an E17 base but is spherical in shape.  It is rated at 120 volts and 40 watts.

The following is a summary of what I have found:

Pilot Light V12 6008 6.3 volts 250 ma blue bead D type #46
Pilot Light (Shadow Tuning) V13 6008 6.3 volts 250 ma blue bead D type #46
Cabinet Light V14 6600 6.3 volts E17 base sewing machine shape?

I am seeking information on the Cabinet Light bulb replacement and hoping my research concerning the Pilot Lights is correct.

[Ron Ramirez]

You're partially correct.

The dial and shadowmeter lamps are indeed type 46, 6.3V @ 250 mA.

The "cabinet lamp" (which illuminates the grille) is an appliance or sewing machine lamp rated at 120 volts. Notice how this lamp, part (65) on the schematic, connects across the primary of the power transformer so it does not illuminate unless the radio's power switch is "on". A 6.3 volt lamp's filament would immediately vaporize at 120 volts.

The original cabinet lamp was tubular and frosted. Replacement lamps are not frosted, but will not normally be seen unless you get down on the floor and look up at the top of the radio's grille.

I do not own a 15X or 15DX, but I did have a 15X once years ago, and remember replacing the bulb as part of the radio's restoration. I remember the bulb was tubular in shape and may have been a sewing machine bulb with a screw base. I do not remember what size the base was - whether it was candelabra, or that odd size in between candelabra and a typical lamp bulb. I still think in terms of "old school" and am not yet up to speed on the various "E" sizes of bulbs.

[RickC]

Thanks Ron

I should have looked at the schematic instead of relying on the written numbers.

Rick

[Brad Winder]

Use a frosted C9 Christmas light bulb, in your choice of colour. It makes the grill light up beautifully for the season.

[Bob Andersen]

Greetings. It's great to hear from another 15DX owner. I found mine in a basement with water damage and have been slowly restoring it for a decade.

They didn't make very many and I've only seen photos of about 5 other examples.

I'm using a 25W clear Westinghouse bulb in mine as shown in the right.
[Image: https://live.staticflickr.com/7235/70039...b5b4_z.jpg]

Here's my restoration thread: https://philcoradio.com/phorum/showthread.php?tid=4706

[Ron Ramirez]

Thanks for that link, Bob - now I know that "intermediate base" is equivalent to the modern terminology "E17 base".

The correct bulb itself is either T7 or T8 size (tubular).

I think if I had a 15X or 15DX now, I would use an LED like this one:
https://www.1000bulbs.com/product/209031...etail-tabs

Advantage: Less energy usage, and you would likely never have to replace it unless you used the radio several hours a day, every day.

[Mondial]

Ron, I am not sure how well a LED bulb would work installed inside a radio cabinet. 120 V LED bulbs typically utilize a switching supply inside to limit the LED current and generate quite a bit of RFI.

With the close proximity to the chassis and antenna wire, along with direct connection to the shared AC power cord, there might be an interference issue.

[Ron Ramirez]

I've been using LEDs for years now, including LED replacements for small dial lamps such as #44 and #46, with no RFI issues.

I've even picked up small radios while they were in operation and placed them close to an LED lamp or fixture - only when the radio was practically against the fixture did the RFI hash come through.

YMMV of course.

I would be willing to take the chance on an LED such as the one I linked to. If it didn't work (RFI), then only about $3 lost. There is a metal shield under the chassis with a hole in it for the lamp, which should help shield the chassis from RFI.

[Mondial]

Yes, that bulb you recommended probably would not be an issue. I took a close look at the photo and the smaller size screw base would have no room for a switching supply. Most likely it just uses a series capacitor for current limiting, generating no RFI.

The miniature #44 and 47 LED replacements are also no problem as they just use series resistors to limit current. I've taken a couple apart and its amazing how much they pack into that tiny base. There is a bridge rectifier, filter capacitor and two dropping resistors on a tiny circuit board just under the actual LED.

Its too bad they don't seem to make the #40 style miniature screw base lamps in LED. I have had to take wedge base LEDs and disassemble to fit them to old screw bases from burned out bulbs.

[Ron Ramirez]

There are LED replacements available for miniature screw base lamps requiring 6.3 volts:

https://cointaker.com/products/1482

I use these in my RCA sets. They work fine.

[Mondial]

Thanks for the link. They look nice and certainly beat rebuilding the old screw base bulbs.

I have been using these for 44/47 replacements and they have been working out very well:

https://www.ebay.com/itm/264471578757?ha...SwW5RdhA05

[Ron Ramirez]

Are those 44/47 replacements bright enough?

Before I discovered Pinball Life and Coin Taker, I tried some frosted 44/47 LED lamps from the auction site (I'm sure it was a different seller). They were very disappointing - not very bright. I use Pinball Life's 44/47 replacements and have always been pleased with them.

https://www.pinballlife.com/ablaze-low-p...-dome.html

These are roughly the same price as the bulbs in your link.

[RickC]

As the replacement bulb in my unit is a 40 watt bulb I intend to replace it with a C8 40 watt or an led with the same lumen.

My radio was a lucky find as it appears to have the original finish and I believe never saw a basement.  I replaced the grill cloth as the one installed was clearly cloth from the seventies.  Unfortunately, I could not find a reproduction which matches the original.

           

[Bob Andersen]

Yowzah! That is in amazing condition! Top of the line from 1932. Thank you for the excellent photos.
I was able to get my replica grille cloth shortly before the supply ran out. New patterns have slowly become available again do there is hope.

[OldRestorer]

What a beautiful radio...