How do I date Philips, Sylvania, GE and other brand's fluorescent tube? I specifically want to know the date of my Canadian Sylvania F25T12 tubes, I have a photo of one of them.

How do I date Philips, Sylvania, GE and other brand's fluorescent tube? I specifically want to know the date of my Canadian Sylvania F25T12 tubes, I have a photo of one of them.

Usually date codes are a closely guarded secret and aren't meant to be discussed openly.
The Philips date codes, not sure if I can release how to decipher them or not.

Quote from: wattMaster on June 30, 2016, 06:13:44 PM

How do I date Philips, Sylvania, GE and other brand's fluorescent tube? I specifically want to know the date of my Canadian Sylvania F25T12 tubes, I have a photo of one of them.

Usually date codes are a closely guarded secret and aren't meant to be discussed openly.
The Philips date codes, not sure if I can release how to decipher them or not.

Is that a joke? If not, what about PM?
I know that Philips codes go like this:
Position of letter in alphabet = Month
Number = Last number of manufacturing year.

Quote from: RCM442 on June 30, 2016, 07:53:47 PM

Quote from: wattMaster on June 30, 2016, 06:13:44 PM

How do I date Philips, Sylvania, GE and other brand's fluorescent tube? I specifically want to know the date of my Canadian Sylvania F25T12 tubes, I have a photo of one of them.

Usually date codes are a closely guarded secret and aren't meant to be discussed openly.
The Philips date codes, not sure if I can release how to decipher them or not.

Is that a joke? If not, what about PM?
I know that Philips codes go like this:
Position of letter in alphabet = Month
Number = Last number of manufacturing year.

No, it's not a joke, and with the Philips date codes, you skip the I

Quote from: wattMaster on June 30, 2016, 08:08:47 PM

Quote from: RCM442 on June 30, 2016, 07:53:47 PM

Quote from: wattMaster on June 30, 2016, 06:13:44 PM

How do I date Philips, Sylvania, GE and other brand's fluorescent tube? I specifically want to know the date of my Canadian Sylvania F25T12 tubes, I have a photo of one of them.

Usually date codes are a closely guarded secret and aren't meant to be discussed openly.
The Philips date codes, not sure if I can release how to decipher them or not.

Is that a joke? If not, what about PM?
I know that Philips codes go like this:
Position of letter in alphabet = Month
Number = Last number of manufacturing year.

No, it's not a joke, and with the Philips date codes, you skip the I

I would have said that, but I did not know due to the font if it was a I or an L.
Wow, it's crazy that date codes are near trade secrets! PM communication is starting to sound like a good idea.
What actions would the companies take to make sure that date codes are not talked about?

Some Chinese Philips lamps use the I in the date code rotation.  I have at least 2 examples of this.  Just a warning for new players.

Some Chinese Philips lamps use the I in the date code rotation.  I have at least 2 examples of this.  Just a warning for new players.

Do 1 and I look the same?
For now I just need to be able to decode Sylvania and GE lamps.

Quote from: randacnam7321 on July 25, 2016, 04:49:43 AM

Some Chinese Philips lamps use the I in the date code rotation.  I have at least 2 examples of this.  Just a warning for new players.

Do 1 and I looks the same?
For now I just need to be able to decode Sylvania and GE lamps.

PMd you.

Does anybody here know how to decode the date codes?

Does anybody here know how to decode the date codes?

GE date codes are a trade secret, so not good to talk about decoding them here.
Sylvania date codes I'm still working on and not sure if they are as guarded. 

My understanding is, as long as you/we reverse enginner them by your/our own thinking from the lamps on hand only, dont use GE's inside information, and haven't signed NDA for GE, we have no obligation to keep their secrets

My understanding is, as long as you/we reverse enginner them by your/our own thinking from the lamps on hand only, dont use GE's inside information, and haven't signed NDA for GE, we have no obligation to keep their secrets

.           And of course fine if you follow no them on a website elsewhere , where they have become public domain. The majority of the dates that interest collectors are 'legacy historic' , thus harmless discussion topics between those of us inventorising our collections and  identifying them by date. For GE, I worked them out by going through pics of dated lamps, and comparing positions of the markers, to work out how to read them. With Sylvania,  the now closed factory at Shipley in England dated a dozen or so of my tubes over the telephone during the 80s, putting lamps next to each other, I drew up a table, and filled gaps where I found new lamps. Was still unsure, tho until I found a lamp for the current year at the time. It had the expected number of dots in the 'right place' so hey bingo. Currently osram and Philips make no secret of the dates on their European T5 lamps, printing an actual month and year on the cap.. Osram include their weekly alpha next to it, thus their code is spelled out !

Maximum they can do when you reverse engineer and publish their coding system is to change the system they are using, so the already published table won't work anymore...

If you reverse engineer it yourself from a publicly available material (an item offered for sale is legal wise already "publicly available"), that is your art and it is solely up to you, if you share it or not and how. Those companies have no say about that at all, it is you and not they, who own the all the rights to the reverse engineering work you did.

If the reverse engineering was based on an item, which was brought public illegally, it depends on if you knew about it or no.
Of course, the only thing you can not do is, when you have signed an NDA (or similar) with a company for certain topic because you have worked for/with them (so you needed access to that information for your work), you can not disclose anything regarding that topic.

Why are date codes trade secrets?

Why are date codes trade secrets?

Generally everything that the user does not really need to know about the product is assumed as a trade secret by some companies. And the date code belong to this type of information.
 The date codes may reveal, how the manufacturing is progressing (large batches made in a short time and then sold out for long time, or steady production), that may suggest the overall volume that is manufactured and so on. Plus it helps them conceal which lamp belong to which batch, so hiding batch problems from customers.

On the other hand many companies, mainly the quality minded, made intentionally the batch identification open and straight forward. With that they send a clear message: If there would be any problem with a batch that pops up only later in use, this identification will make sure such problem get recognized way sooner, all possibly affected pieces may be identified way sooner too, so the consequences of that problems could be greatly minimized.