Scope not Showing Correct Square Wave

[Samuel Groner]

Also, when it asks for a time marker voltage with a repetition time of 1 us and an amplitude of 80 mV p-p, do I just need to convert the repetition time to a frequency for the oscillator?

Sure.

Samuel

 

[techbiker]

Also, I hate to bother you guys again but my scope's crt light filter has been bleached by the lights at the top of the screen. Is there any inexpensive source of new colored plastic light filters? I guess that I could cut one to fit.

Thanks

 

[bear]

By the way, I have attached a picture of the front knobs with the blue tips removed. Notice the gray plastic pieces on top of the collet nuts. I cannot seem to remove these easily without destroying the knobs themselves. Let me know if you need more pictures.

Odd. Very odd indeed.

How about taking the covers off some of the small knobs and see what is in there?

I don't recognize what looks like some sort of button head nylon thing in the pictures. I have no idea what that is. My Phillips scopes all have brass collet nuts in that spot. Is it nylon, or did someone throw epoxy in??

Oh, afaik that is just thin colored plastic. Usually about 0.68" or less... approximately. Blue green type color.
Polycarbonate would be nice.

 

[techbiker]

Hi again!

Sorry about the slow reply. Those plastic pieces appear to be nylon as they are virtually perfect circles. 🙁 I wonder how they can be removed without destroying the knobs? I ordered a new blue plastic optical filter from edmund optical Anchor Optics - Optical Cast Plastic Color Filters Hopefully this will be a big improvement over the nasty old browned one. I will let you know how it looks!

Elvee, does the 74hc390 itself provide divider networks? Could I use a different IC to pick a different set of networks?

Thanks again

 

[Elvee]

The 74HC390 is a digital divider, not a network (you need both). You could use a 74HC4040 instead, the ouput values would just be less convenient for mental calculations