Tektronix 2336 Scope Sec/Div Switch Issue

[TimeBandit]

My 2336 started acting up today while I was using it to monitor a 1kHz sine wave. I've attached a link to a short video showing what I'm seeing. As I decrease the sweep speed, the sine wave starts acting wonky (technical term). I've never had to do any work on this scope, but I'm ready to dive in with some direction.

https://youtu.be/1P13kJ4kDmU

[bdunham7]

Looks like you aren't triggering properly.  Can you show the whole front of the scope?

[TimeBandit]

Sure. Let me know if this isn't clear enough.

[bdunham7]

 

I meant with everything connected, turned on and set so that the problem is happening.

What I suspect I'll see is that you have it in AUTO trigger mode but the trigger indicator light is not on.  You likely need to adjust the trigger level until the light is on, which should be somewhere in the middle of the adjustment if the scope is working properly.  Unlike many other Tek scopes, this model does not have the AUTO P-P feature which sets the trigger level automatically, so the AUTO trigger mode is 'dumb' and just triggers so you have something to see.  You will almost always want to use this scope in the NORMAL trigger mode.

[TimeBandit]

Sure enough that was it. Thanks for saving me from myself.