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[dellmodelm]

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[emmafrost1]

I have three 1986-'87 1390120s. One weighs 5.5 lbs (2495g), one weighs 5 lbs (2268g) and the 3rd one is 4.95 lbs (2245g). All have matte "rainbow" steel backplates. Question, what could account for the weight differences between the 3? The 5.5 and 5 lbs were made only one day apart (May 12 and 13, 1986). The 4.95 lbs was made in January 1987, but it also has a matte rainbow plate. I'm completely baffled!

There are a few possible explanations for the weight discrepancy between your three IBM Model M 1390120 keyboards.

Different materials: The keyboards may have been made with different materials, such as different types of plastic or metal. This could account for a small difference in weight.
Different manufacturing processes: The keyboards may have been made using different manufacturing processes. This could also account for a small difference in weight.
Different components: The keyboards may have different components, such as different types of switches or keycaps. This could account for a larger difference in weight.
Manufacturing tolerances: There are always manufacturing tolerances, which means that even keyboards made on the same day with the same materials and processes may not weigh exactly the same.
It is also possible that the weight difference is simply due to random variation.

If you are concerned about the weight difference, you can weigh the keyboards yourself to get an accurate measurement. You can then compare the weights to see if there is a pattern. If there is a pattern, you can try to determine the cause of the weight difference.

If you are not concerned about the weight difference, you can simply enjoy your keyboards. They are all still IBM Model M 1390120 keyboards, and they are all still great keyboards.

[fohat]

There are a few possible explanations for the weight discrepancy

The factors you listed are real but would seem to be almost trivial.

A discrepency of 250 g, over half a pound - that is huge.

[Muirium]

Moderator's note:

Someone (whose first album went platinum, a first for a female country artist, I gather…) reported said post for being 'obviously AI generated'. I quite agree. Even the username fits our resident spammer's house style. No hidden SEO links in there, however. Yet.

[kbdfr]

[…] Question, what could account for the weight differences between the 3? […]

[…] If you are concerned about the weight difference, you can weigh the keyboards yourself to get an accurate measurement. You can then compare the weights to see if there is a pattern. If there is a pattern, you can try to determine the cause of the weight difference. […]

Already did all that? Well, then ask your question on DT.
Oh, already did? emmafrost1 seems not to have noticed

[Muirium]

There are many helpful AI comments available in generally available sources of availability, many of which feature artifice if not intelligence. Examples include Kyrgyzstan and Aston Villa…

[JP!]

If you are not concerned about the weight difference, you can simply enjoy your keyboards. They are all still IBM Model M 1390120 keyboards, and they are all still great keyboards.

"Beauty is truth, truth beauty,—that is all
Ye know on earth, and all ye need to know."

-Ode on a IBM Model M 1390120

[Muirium]

Thou still fair ravished bride of disquietness,
Thou foster-child of loudnesss and fast-finger’d time,
Sharktastic historian, who canst thus express
A thund’rously clicky tale more sweetly than our rhyme?

—Keyts

[paperWasp]

dtai.png (24.97 KiB) Viewed 2272 times

[Muirium]

Fair’s fair. We already have a Spammer’s Lounge after all.