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geekhack Marketplace => Great Finds => Topic started by: berserkfan on Sun, 12 January 2014, 02:30:04

Title: Could this be a beam spring? Auction ends in 12 hours!
Post by: berserkfan on Sun, 12 January 2014, 02:30:04
http://www.ebay.com/itm/Vintage-Computer-TRS-80-Model-4-MINT-CONDITION-RARE/171210731109?_trksid=p2045573.m2102&_trkparms=aid%3D555012%26algo%3DPW.MBE%26ao%3D1%26asc%3D298%26meid%3D4060275290665814203%26pid%3D100034%26prg%3D1079%26rk%3D7%26rkt%3D8%26sd%3D151065545447%26

I find this very intriguing. Maybe someone will know something.
Title: Re: Could this be a beam spring? Auction ends in 12 hours!
Post by: Aer Fixus on Sun, 12 January 2014, 02:34:17
http://www.ebay.com/itm/Vintage-Computer-TRS-80-Model-4-MINT-CONDITION-RARE/171210731109?_trksid=p2045573.m2102&_trkparms=aid%3D555012%26algo%3DPW.MBE%26ao%3D1%26asc%3D298%26meid%3D4060275290665814203%26pid%3D100034%26prg%3D1079%26rk%3D7%26rkt%3D8%26sd%3D151065545447%26

I find this very intriguing. Maybe someone will know something.

I thought beam spring was IBM only? Also, I'm pretty sure this is a linear switch. The one I typed on felt like foam and foil, but there were lots of iterations to the TRS-80 that it could be something else.

Edit: The TRS-80 Model 4 is definitely discrete switches, so not beam spring or foam and foil:

(http://farm3.staticflickr.com/2201/2456185118_12e132848c_n.jpg)

Edit2: It appears to use discrete rubber dome switches...
http://www.vintage-computer.com/vcforum/showthread.php?13610-Keyboard-repair&highlight=keyboard+switches (http://www.vintage-computer.com/vcforum/showthread.php?13610-Keyboard-repair&highlight=keyboard+switches)
(http://www.brutman.com/pics/TRS80_Model_4_Keyswitch.jpg)
Title: Re: Could this be a beam spring? Auction ends in 12 hours!
Post by: Findecanor on Sun, 12 January 2014, 02:59:30
Interesting...

The switches of a TRS-80 Model 3 can be seen here: http://geekhack.org/index.php?topic=21206.msg402810#msg402810. They look like Vintage Alps (http://deskthority.net/wiki/Alps_vintage_tee_mount).
I have seen the TRS-80 Model 1 also have this mechanical switch.
So they changed the switch type for the Model 4 ...