Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: rafe on April 09, 2022, 05:53:35 pm
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Anyone know where to get a replacement neon bulb for a SICO tw11 tube tester? It is listed on the schematic as NE-2....I have no idea other than here as to where to start looking, Thanks and regards, Rafe
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I jumped the gun . The night is fallin and the music's callin and I got to get down to "BULB TOWN"
Thank
https://www.bulbtown.com
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NE-2s have got hard to find. I guess LEDs stole their market. Yes, BulbTown is a good bet.
https://www.bulbtown.com/neon_lamps_and_light_bulbs_s/909.htm
Going forward does not look better. Aside from reduced demand discouraging production, they don't start well without a pinch of radioactivity to goose the ions, and it turns out that much of the world's Neon was produced in Ukraine. (Mostly for semiconductor fabrication, not little lights, but it's in short supply.)
Shipping a NE-2 is much more than the bulb. While you are there, look at 200W Incandescent for $3. Good for lamp-limiters to start-up any new or sick amp, even to play smaller amps at 80%. Get a few, they probably are not coming back.
https://www.bulbtown.com/200PS25_IF_130V_5M_200_Watt_PS25_IF_E26_Base_p/60154.htm
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https://www.amazon.com/A1A-NE-2-Hours-Standard-Brightness/dp/B007XKW0MQ/ref=sr_1_4?keywords=ne-2+neon+bulb&qid=1649600857&sr=8-4
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https://www.amazon.com/A1A-NE-2-Hours-Standard-Brightness/dp/B007XKW0MQ/ref=sr_1_4?keywords=ne-2+neon+bulb&qid=1649600857&sr=8-4
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I jumped the gun . The night is fallin and the music's callin and I got to get down to "BULB TOWN"
Thank
https://www.bulbtown.com
+1
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https://www.amazon.com/A1A-NE-2-Hours-Standard-Brightness/dp/B007XKW0MQ/ref=sr_1_4?keywords=ne-2+neon+bulb&qid=1649600857&sr=8-4 (https://www.amazon.com/A1A-NE-2-Hours-Standard-Brightness/dp/B007XKW0MQ/ref=sr_1_4?keywords=ne-2+neon+bulb&qid=1649600857&sr=8-4)
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At Amazon, the same product can be in or out of stock depending where you are. Not just country but where you are in their distribution warehouse system (to control shipping costs).
I know a book author who got hung-up until Amazon got a copy into every warehouse.
You never really know until it is in your hand.
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It appears that the bulb was not the issue. It calls for an.01 capacitor but doesn't tell me a voltage for it There is a domino looking cap in there that is 10000 i pulled it as I believe that is the .01 any idea of voltage?? I am replacing caps in a small VTVM also and there is an electolytic .01 1000v so that makes me go hmmmmmmmm on the tw-11 tube tester cap voltage. Thanks PS the highest voltage shown is 250v coming out of the transformer it then goes through a 5k resistor
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typical NON Ecap is 600vdc, they usually go up from there, 1kv was pretty common in the way-back-days
other than audio couplers, they are used to suppress transient spikes. those spikes can get real big over a real short time, but long enough to blow a hole through the cap.
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I ordered one .01 600 v for the tube tester and 2 .022 @1000v that should get me .01 @2000 volts for the VTVM, It was 2000 v in the VTVM not 1000v..... :think1:
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I put in the .01 still no neon light ....but testing still works ....somehow I misplaced the other 2 caps that I was going to use ...Vanished between my car and the house ...although I think they made it to the house .... I am going to check the 2meg resistor ....It might be out of tolerance enough to affect the bulb?
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Is this neon the leak tester? It may not glow without a leaky tube?
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There is a domino looking cap in there that is 10000 i pulled it as I believe that is the .01 any idea of voltage??
Domino caps use color coded dots to tell you the value and voltage. Post a hi-rez pic of the cap and we may be able to decipher it. Or follow this link if you want to decipher for yourself...
http://www.tpub.com/neets/book2/3g.htm
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Is this neon the leak tester? It may not glow without a leaky tube?
It tests for shorts but also for filament. It was working fine then quit. I replaced the bulb, the .01 cap and the resistor 2meg (today) .....I will follow up on next post
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Domino caps use color coded dots to tell you the value and voltage. Post a hi-rez pic of the cap and we may be able to decipher it. Or follow this link if you want to decipher for yourself...
http://www.tpub.com/neets/book2/3g.htm (http://www.tpub.com/neets/book2/3g.htm)
I am going off the schematic it calls for a .01 but doesn't give voltage I put in a 450v .....The resistor that goes across the bulb calls for a 2meg(on schematic) it had a 2.2meg in there but tested closer to 3meg. I am thinking(guessing) that by replacing the bulb and trying it before replacing those components i caused a re-enactment of the first bulb failing?? the cap had 1000000mmn....I'm not 100% on the mmn but it was something close there were no other caps in that area on the schematic ...no dots just the shape of a domino and black not quite square but not as long as a domino
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Solved ! It was the 100k resistor, The only one I had was 1/4 watt but that did the trick should be good to go for a while. The 2 .022 1000 volt caps i lost were actually for a VTVM I am working on it called for a .01 2000v cap .....found them and got them in ....looks like one of the tubes is not lighting up ...I'll see what I haveas far as that tube goes
. That cap was mmf somehow it translates to .01 ?? I could not find much info on it
Thanks
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I believe I learn't mmf as milli-microfarad
look for a sketchy filament connection for your un-lit tube
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Thanks shooter will do . I can actually take it out and test it for filament shorts and condition. it's a heath v-7 so I'm sure I can find a schematic . The caps I replaced were definitely bad ....need to make a DC lead too 1/4" phono.
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I believe I learn't mmf as milli-microfarad
mmf is micro-micro-farad. I learned to call it mickey mike. Same as picofarad.