Indicator lights on 1390120?

[y11971alex]

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.



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.

 

[chyros]

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.

[y11971alex]

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?

[0100010]

Just an older component that one particular user in the past liked to hype up and talk about a lot.