That's weird.


I was not able to download 2001 version of ANSI C78.81, but all later versions list *only one* 60 inch instant-start T12 tube which is 40(42)W version @425mA 107V

No 50W T12 slimline at all in ANSI standard. Already got obsolete and was removed?

your unlikely to find many of the more 'odd ball' Slimline and HO tubes in the ANSI standards, so I would not fret about it


there are a whole bunch that are meant for sign usage or fitting within a certain space etc, the Americans really went to town with the whole "fixed current and a whole bunch of tubes of various sizes" since if you say have a ballast that can run 2ft 4ft 6ft & 8ft 425mA single pin tubes theres no reason it cant run a 5ft tube or a 7ft one etc



its not hard to guesstimate that the arc voltage of a F60T12 425mA slimline tube (all single pin slimline T12 tubes are the same 425mA) will probably be about the 130V mark


@tigerelectronics, if they will reliably strike up on 400V between phases mains, and you have ready access to that, then thats what I would go with for simplicity sake, with that you can just use a couple 220V-240V chokes in series to get the right ballast impedance, I would start with 2 regular 36W chokes weird in series, measure the current and take it from there

Yeah the oddball HO and SL lamp lengths were mostly intended for things like signs, the SL for indoor signs or outdoor signs in warmer climates and the HO for outdoor signs in colder climates. The odd length slimline lamps have also seen some use in mass transit, particularly buses, streetcars, and trains along with general and accent lighting for midway games and carnival concession stands.

The 2ft HO lamps were also used for general lighting in cramped spaces. I think some ships used them in compact fixtures.

IIRC there was even a specialized reflector 18" and 24" VHO lamp from Sylvania which was intended for use in mining equipment.

Unfortunately, the tubes never made it here so I’ve put this project on the back burner for a while. I’ll try to find some other cool vintage tubes to use for the DIY light fixture, but right now I sort of lost motivation when the tubes didn’t make it. The postal service managed to screw up really bad and somehow they got stopped at one of their terminals and sent to a wrong address and it just became a huge mess. I don’t even know if the seller got them returned, I doubt it because I haven’t got a refund I’m very much at a loss and I don’t know what to do to correct this, the postal service is not being helpful whatsoever in resolving the lost package.

I'm sorry to hear that, that sounds like classic postal services, breaking/loosing stuff and not taking responsibility.

@LightBulbFun did you ever happen to compile a list of these oddball tubes?

Indeed, I’m just an insignificant little private customer for the postal service and if they don’t see any profit, they are not interested in helping me whatsoever, I hate how everything has become about money these days, nobody does anything to be nice anymore (((((((


Oh yes! I’m also curious about the list that’s something I look forward to regardless if I have the tubes or not