[solved] Problem With horizontal positioning on Tektronix 2235 Oscilloscope

[solder_boy132]

I have a Tektronix 2235 oscilloscope. I replaced a broken BNC connecter on the scope, and then when i power it on, the trace is move to the left. I use the horizontal positioning knob to move it to the right, but it doesn't go all the way. Here is the link of the video where i show what is wrong: https://youtu.be/vFokxxRSsS4 Read description for more details.

[bob91343]

You need to measure some voltages in the horizontal circuit.

[KevinA]

Step 1, turn down the brightness; you will burn the screen.


Measure the voltage on P9788 and P9778, and follow it back to the horizontal section to find the wrong voltage(s)

[solder_boy132]

ok, and also, its the camera, its actually dim.

[David Hess]

Is the sweep shortened to about 1/2 or is the horizontal calibration off by a factor of 2?  If so, then you may have knocked one of the leads off which go to the CRT horizontal pins.

[solder_boy132]

Having a bit of trouble removing the volts/div board. The problem also may be that its just old. It hasn't been repaired or serviced since 1989.

[bob91343]

1989 is old?  Not for most of us.  I think my granddaughter was born around then.  Most of my equipment is older than that.

[tomthepom]

I've received one of these scopes for Christmas but just got around to testing it today. Unfortunately, it has exactly the same issue yours has.

Could this be some sort of issue with the calibration of the horizontal gain etc. (section 5-14 onwards in the service manual)? Sorry if this sounds stupid, I'm a complete noob when it comes to scopes and electronics in general really.

Here's the link to the service manual I found as well in case its needed: https://www.palomararc.org/Manuals/Tektronix_2235_service_manual.pdf

[solder_boy132]

Did you get it on ebay?

[solder_boy132]

Well  fixed my scope. Turns out all i had to do was lend it to my brother, have him drop it while carrying it, and immediately giving it back to me! The horizontal works just fine now. I do not know why, but I'm guessing loose connections.

[bob91343]

I am embarrassed to admit how many times I have repaired units that way.  The hammer can be your best friend.