Meaning of red border/markings on old Tektronix analog scopes (images included)?

[SharpEars]

What does it mean if the 246* (e.g., 2465/2467) oscilloscope screen has a red border around it and red grid markings (silkscreen)? Is it a different (better?) type of screen than the normal black border/markings oscilloscope screen? Or is this just a cosmetic thing?

I am talking about a screen like this:



Notice the red border and grid around/over the screen. It is found on some models but not on others. What does it mean?

[Andy Watson]

It means that the graticule illumination has been turned up - such that the graticule appears when you use your oscilloscope camera.

[Electro Fan]

It means that the graticule illumination has been turned up - such that the graticule appears when you use your oscilloscope camera.

Yep, if you turn down/off the SCALE ILLUM knob (to the left of the power button), the display will very likely turn to the standard blue color you generally see on Tektronix analog scopes.  Almost any Tektronix analog scope you see that has the SCALE ILLUM knob (if it is working, which it generally will be) can be made to look like the display shown in the photo posted at the top of this thread if you turn the SCALE ILLUM knob fully up/on; by turning the knob down/off it can be made to look like the more often seen blue display.  It's a standard feature - you can make most any analog Tek scope (if it has the SCALE ILLUM knob) have either appearance, and you can have a middle ground with the red graticule lines and the red border overlay plus the blue background showing at the same time.  It's just a function of how far you turn the SCALE ILLUM knob.  You will find the SCALE ILLUM knob on various Tektronix 22XX and 24XX models.  On 7XXX models it is called the GRAT ILLUM knob.

[Gyro]

Yep, if you turn down/off the SCALE ILLUM knob (to the left of the power button), the display will very likely turn to the standard blue color you generally see on Tektronix analog scopes.

The scope can be fitted with a clear screen filter rather than the more common blue contrast one. - many Tek scopes were originally supplied with both. Yes, turning down the graticule illumination will get rid of the red color with these, but it will still be a green trace on a light background, not blue.All filters have a black boarder that hides some of the outside visible border.

I can't see a black border in the photo so it looks as if no filter is fitted. Check whether the scope does actually have a clear plastic filter fitted in front of the CRT glass, it needs to be there for implosion protection. If you prefer the traditional blue, then blue filters can be picked up on ebay or other surplus outlets (particularly in the US).

P.S. Make sure you get one for the correct model (or series) as their shapes vary.