About graticules on old Tek scopes.
There are 2 different styles:
1.) graticule field includet in the front of the CRT
2.) a plexi glas what have inside the graticules, in front of the CRT screen.
On some pictures here you have seen red colored graticule fields. This are scopes at 2.).
The graticueles glass have holes up an d down, you can`t see them bec. they are covered from the bezel front plate.
In upside are 2 bulbs what do the graticules illumination, the heads of them are exactly placed in this holes of the glas.
The graticules glas have that holes in upside, also in downside. The both holes in downside are inside painted transparent red ! So, when you turn the glas to have that holes upside, the old Tek will display a red graticules field, not turned a white
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
To order spare bulbs to repair a Classic Tek look for bayonette bulbs 6.3V 0,3A GE#47
greetings
Martin