Sciencemadness Discussion Board

Mel-Temp Replacement Bulb

VialsOnRye - 14-4-2023 at 12:43

Hi folks! I've recently acquired a nonfunctional Barnstead Mel-Temp melting point apparatus; purportedly the only issue is a burnt out bulb. Having disassembled the unit, the bulb is an unusual one, with a non-threaded base. The unit is discontinued, and the bulbs seem to be as well, although I cannot find much information regarding this unit's maintenance (Model 1101D). If anyone has a corresponding manual, or information about a bulb that would fit this purpose, I would love the help! I'm including photos of the bulb, its housing, and the information placard on the bottom of the unit.

The measured dimensions of the bulb itself are:
Base diameter 1.5cm
Widest glass bulb diameter 1.85cm
Entire height 4.45cm

IMG_4721.jpeg - 794kB IMG_4722.jpeg - 892kB IMG_4723.jpeg - 1.3MB IMG_4724.jpeg - 1.5MB IMG_4725.jpeg - 1.1MB

Rainwater - 14-4-2023 at 13:14

Ok, easy bake oven.... that is a "can dc bar" style socket, originally used back in the eddision vs. tesla patient wars. But does not mean it's a dc bulb. As long as you use rms voltages, doesnt make a difference.

Found a unit on ebay, says it is 200 watts. Thats total for the unit. Not the bulb.
From your picture, i can only make out the last 3 letters printed on the bulb socket

If you very carefully test the live socket, at max power to obtain the voltage and current type, it will be easy to find a bulb to match.
And you can do tye poor mans trick of powering the bulb, then rolling it to the point the filliment makes connection and welds itself back. No greater feeling of pride than when it works

Sulaiman - 14-4-2023 at 14:19

The imprint on the lamp is 250V 6W.

Bayonet connection (BC) type B22 I think.

Edit : 15mm not 22mm...

[Edited on 15-4-2023 by Sulaiman]

Rainwater - 14-4-2023 at 14:35

Maybe this one

Cathoderay - 14-4-2023 at 15:38

It would be vitally important that you read the voltage rating on the bulb base.
It isn't quite clear enough in the photo.
DC in this case means Double Contact (on the bottom).

Are the two projections on the side of the brass base at the same distance from the bottom?
If they are at the same distance then it is a DC Bayonet base, if they are at a different distance then it is a DC Index base.

The bulb is probably a S-8 shape, US automobiles used to use this type for tail lights years ago. But those were rated 6 or 12V.

I have a miniature lamp catalog but none are listed that are rated for voltages over 55V.

[Edited on 4/14/2023 by Cathoderay]