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geekhack Community => Keyboards => Topic started by: y11971alex on Sat, 23 April 2016, 12:24:40

Title: Indicator lights on 1390120?
Post by: y11971alex on Sat, 23 April 2016, 12:24:40
Hello GH!

I received my 1390120 after a week of anxious waiting, along with two 1391472s, one with a completely disintegrated barrel plate due to DHL's gentle handling.

(http://i156.photobucket.com/albums/t2/themiclesia/5A34C58D-F662-4FA3-8755-5B01DE058243_zpstmtr6wop.jpg)

There are two mystery components on the PCB: a set of pins for what I thought was for indicator lights, and a partly transparent component on the board with 4.00 mHz p/n 1351544 and TEW5 29B.

 :D
Title: Re: Indicator lights on 1390120?
Post by: chyros on Sat, 23 April 2016, 12:31:01
MANDOLIN CRYSTAL IDENTIFIED

The 1390120 is a Model M that was made to be compatible with the XT (even though it also speaks AT), so it has no lock lights.

The transparent thing is a crystal oscillator that's only present on very early Model Ms.
Title: Re: Indicator lights on 1390120?
Post by: y11971alex on Sat, 23 April 2016, 12:34:17
MANDOLIN CRYSTAL IDENTIFIED

The 1390120 is a Model M that was made to be compatible with the XT (even though it also speaks AT), so it has no lock lights.

The transparent thing is a crystal oscillator that's only present on very early Model Ms.
What's a Mandolin Crystal?  Is that something like a quartz oscillator in a watch?
Title: Re: Indicator lights on 1390120?
Post by: 0100010 on Sat, 23 April 2016, 12:41:00
Just an older component that one particular user in the past liked to hype up and talk about a lot.