Remarkably, there are now about 60 photographs on LG and elsewhere of ancient Mazda fluorescent lamps, in both GE and Westinghouse brands.  It seems that many owners are unsure of their production dates, and the suggestions are sometimes inconsistent with other lamps having the same code.

I have therefore compiled photos of all etches and end caps into a single document and tried to arrange them in sequential order according to their actual production date - see linked file.  My apologies in advance to anyone who may object to the use of their images - wherever possible I have cited the owner and provided a link to the relevant file.  I can remove any images if their is a real objection, but hopefully this file will prove helpful to all.

The result is an introductory page to each section for GE-Mazda, Westinghouse-Mazda and early GE lamps, which attempts to decipher and clarify the codes which I believe are more complex than originally suspected, and may also indicate the place of manufacture.  Also included are some observations on the dates at which the lamp and cap design/construction was modified.

I would be very grateful to receive the feedback of any members who may know more, either to confirm this proposal or suggest possible improvements.  I can share the file in MS Word format if that would be helpful to make adjustments.

Oh thats a very Awesome writeup/research paper you have put together James! its been most interesting to read through it, I for example had noticed that sometimes some lamps would use dots instead of dashes, or others would not quite have the dashes aligned with the letters, so its very interesting to find out about the details of that


for the sake of completeness if it helps with the research at all, my Mazda F15T8/B did incredibly come with its sleeve, or whats left of it after almost 85 years! perhaps the patent list might help narrow the date down a bit?


also there is 1 Mazda T17 tube LG

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-101596

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-46244


as well as a slightly later General@Electric 100W T17 tube

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-78002

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-78003

Thanks for those extra links, I will have to add them to the list!

And incredible that your blue sleeve lists individual patents per colour, I will have a look at those next week.

I hope with some more input we shall be able to finally crack this code and publish a sheet that everyone can agree with.  Then the same for the later GE’s where there are even more conflicting interpretations.

I saw you were asking about Sylvania codes for your new F4T5BLB.  It looks to me as though there is space for 6 dots on the upper row, so maybe that is the month and the year is below?

Best rgds,

James.

No problems! I also find if you search the gallery for "brass ender" or some variation of brass and and some other search term, you can turn up a few extra ones especially the ones that are not Mazda branded (as an aside its very interesting to read that Mazda was banned as a brand/name? I never knew it was banned, do you know why that was? I always thought they just decided to stop using it!)

for example here are a couple I see that are not on the list so to speak

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-231387

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-86505

(BTW I would recommend using the direct link URL when linking to the gallery rather then the "https://www.lighting-gallery.net/gallery/displayimage.php?album=" type of link you get if you copy from the URL bar when browsing, sometimes those links can fall out of position and end up linking to different picture in the same gallery and also the direct URL links are a bit shorter/neater )


I look forward to hearing what you dig up on the patents front, I did think I should post it since I have been wondering if it is quite early relatively speaking since some of the colours just say Patent pending without any patent numbers even, so I do wonder if this dates it to 1939 rather then 1940? and perhaps could help us narrow down when the etch styles changed maybe? but thats just idle thoughts, hopefully the actual patents will give us a more concise data and also provide you with more juicy technical details for your own research

@ James,

I have few interesting GE Mazda lamps.

In picture there one nickel cap, two brass cap, and others are fake brass (Steel) caps. 

Excellent job James on the write up, all info looks to be accurate and spot on. I have the 1942 Mazda daylight lamp. I’m definitely looking forward to the GE date code write up you mentioned or making up. I have GE’s date code system memorized pretty well if you would need any assistance. Not sure if you’d be interested or not, but it would be really great to have a date code sheet made up for early Westinghouse lamps and early Duro-test lamps, as there’s very limited info on either.