What type of bulb is this?

JimBanville

Active Member

• Aug 13, 2013

• #1

Strobe or LED or incandescent? It's blown. It's on my SL-B2. What should I do to replace it? Thanks!!!!

http://www.audiokarma.org/forums/album.php?albumid=3108&pictureid=20716

 

illini

The Past is Alive

• Aug 13, 2013

• #2

It's a neon lamp. That's probably a current limiting resistor next to it, connected in series....

 

gadget73

junk junkie

Subscriber

• Aug 13, 2013

• #3

yessir, standard neon lamp. They seldom go bad, but if yours does not work, check the resistor to see if it has failed or drifted out of spec before replacing the bulb.

 

JimBanville

Active Member

• Aug 13, 2013

• #4

Thanks! Do I just measure the resistance of the resistor while mounted on the board? Can you read what value it is? Do those often fail? If I wanted a cheap and easy and quick fix, could I just slap an LED and matching resistor on there from RadioShack after I measure the voltage feeding it? Thanks again

 

Pio1980

AK Member

• Aug 13, 2013

• #5

Yep, glow lamp. There is often an oily paper capacitor ca 2.2uF/250V associated with this circuit, particularly in Sony TTs that goes bad. Look for a capacitor with a voltage rating much higher than the others in the bulb's power circuit, these capacitors are inexpensive.

 

illini

The Past is Alive

• Aug 13, 2013

• #6

It's rare that they fail. I'm looking at the schematic for the sl-b100 - probably the same neon lamp schematic as your table - and you should measure about 10k in-circuit resistance. The b100 uses a 10k 1Watt resistor in series with the lamp. The lamp/resistor are in parallel with the primary side (120VAC) of the transformer. The resistor may also have temperature resistant properties (green body) so be aware of that. I would procure the sl-b2 service manual to be sure.

 

petehall347

the brandy coffee man

• Aug 13, 2013

• #7

resistor is 10k ohms it can be measured in circuit . as said it runs off the mains voltage .
check the soldered connections .
if you want to find a new lamp in a hurry crack open an old extension lead that is fitted with a neon lamp and use that . that's if you have an old one of course

 

gridleakrick

Well-Known Member

• Aug 13, 2013

• #8

That is a special high current, high brightness version of the classic NE2 neon bulb and has been totally unavailable for years. The giveaway is the 10K current limiting resistor in series with it. For 110VAC, a standard ne2 uses a 100K resistor and the NE2H (regular high brightness version) uses a 33K resistor.
The Technics part number is SFDNE2HU. A quick google search shows several companies out of stock but claiming they can get it at about $7 each. I don't believe them but it is worth a try.
Your best bet would be to change the resistor to 33K, 1 watt and use a NE2H neon bulb. They are available on ebay, and other places, for less than $1 each. If you do not change the resistor, the new bulb will not last long.
Many Japanese turntables from the 1970s-1980s used this special bulb and it is a shame it is no longer available. I'm currently working on a Sony PS-X5 which uses it.
Rick

 

illini

The Past is Alive

• Aug 13, 2013

• #9

gridleakrick said:

The Technics part number is SFDNE2HU.

Click to expand...

Same neon lamp is used on the SL-B100.