Tekronix 2235 Oscilliscope - No Horizontal Sweep - only vertical signal.

Thread Starter


Joined Nov 17, 2008

I am trying to troubleshoot this oscilloscope as a fun project and I was hoping that you can join me on my adventure! I am so excited to delve into this. So much fun!


Tested at warehouse and got a 1khz signal on both channels.
Took home from a smooth ride in my jeep and set it on bench. Next day fired up and it was not working.


I have the Operators Manual / Service Manual / Tektronix repair your oscilloscope guide.

What is it doing? I uploaded a vid to Youtube ->> http://youtu.be/tof9Hp0yYAo

-No traces without using beam find. AT ALL. NONE.
-No horizontal time reading.
-The video shows me doing many tests with the buttons while holding beam find.

I as well as others seem to think this is in the horizontal circuit somewhere. Also there is a chance that one of the buttons is sticking and needs replaced. Either way I was hoping that you all can check out the video so you can see EXACTLY what my scope is doing and maybe you can help guide me for a less frustrating experience.

I am reading the manuals and there is a lot I do not understand with troubleshooting. I do know about all the high voltage and understand how to be safe.

What do you all think? Thank you so much!


Joined Nov 20, 2008
Hi Bruce,

Beam find reduces the x and y deflection down toward the centre of the screen where it can be seen. You then adjust positioning to bring it to the exact centre and release the beam find button. This seems to work so horizontal circuits are mostly working.

Beam find also forces beam intensity to max in case it has been set too low. It looks like beam intensity knob is turned right down. Try turning it up.

If that doesn't work, focus your investigation on the intensity circuit area. You already know pots can fail, and how to fix them.

Good Luck,