Maker Pro
Maker Pro

Tektronix 2235 issue

Stevierayrob82

Jan 14, 2024
2
Joined
Jan 14, 2024
Messages
2
Hi everyone! I'm new here and a beginner of sorts. I bought a Tek 2235 scope on ebay and it worked great upon receipt. I was able to get a nice square wave with the "Amp Cal" (not sire why they call it that. I've seen the port in different places on this scope in videos. I guess the 2335 came in different configurations. Anyhow, when I put my lab together and plugged it in downstairs, I tried the "Amp Cal" again, but I couldn't get a horizontal trace, only a single vertical line that can be made longer, or as short as a dot, using the volts/div knob, and this happens on both channels. it's like the waveform has collapsed into a line. I do get a lit trig'd light, but no action of the horizontal kind. Someone in a group I'm in on FB said he had the same problem, and the culprit was a resistor in the sweep circuit, but then he was booted from the chat for whatever reason. Before I ask for help, I just want to say that, after reading a lot of the pages here, I already love this site, and I'm fortunate to have found you guys! Without further ado, does anyone here have any experience with this type of issue? THANK YOU ALL!
 
Last edited:

Stevierayrob82

Jan 14, 2024
2
Joined
Jan 14, 2024
Messages
2
Additionally, i found that the next morning, the copper "Amp Cal" terminal in the port hole just disappeared after the frustrating night I spent, trying to get a trace on the screen. No idea if it's down in the hole (feelin' so small) or if it was pulled out by the probe and lost. It was hard to keep the probe from falling out. I had to push the probe tip into it kinda hard.
 

Delta Prime

Jul 29, 2020
1,965
Joined
Jul 29, 2020
Messages
1,965
. I was able to get a nice square wave with the "Amp Cal" (not sire why they call it that.
The "Amp Cal" is typically a square wave so you can tweak the capacitance trimmer on your probes to make the square waves trailing edge as straight up and down vertically as possible.
Then your scope and probes are calibrated properly.
If you can't get the probe to display that square wave on the screen attached to the CAL post then you probably have other problems.
Some scopes even have a GND zero display trace button so that you can find the trace if it's been moved off display which lets you set the proper V/H position of each channel as well.
Of course this all depends if you understand how to even use a scope?
Then the manual is your friend...
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,719
Joined
Nov 17, 2011
Messages
13,719
The "Amp Cal" is typically a square wave
That would be Probe Adjust:
1705301350243.png
From the manual:
1705301402700.png
It was hard to keep the probe from falling out. I had to push the probe tip into it kinda hard.
This port is not meant as a receptacle to plug the probe in. It is usually used by lightly pushing the probe tip against the port only as long as required to adjust the probe for a clean square wave display.
I couldn't get a horizontal trace, only a single vertical line
Obviously there is no x-deflection. Check the horizontal settings and the trigger settings. Unless the horizontal deflection section of the scope is defect, a typical user error is a wrong setting.
Do you have a manual? If not, download it from the tektronix website and get acquainted with all the controls and settings options of the scope.
 

Delta Prime

Jul 29, 2020
1,965
Joined
Jul 29, 2020
Messages
1,965
That would be Probe Adjust:
I know exactly what that is.
An honest mistake on your part.
The "Amp Cal" is typically a square wave so you can tweak the capacitance trimmer on your probes to make the square waves trailing edge as straight up and down vertically as possible.
Then your scope and probes are calibrated properly
All my mistakes are dishonest.
:)
 

bertus

Moderator
Nov 8, 2019
3,321
Joined
Nov 8, 2019
Messages
3,321
Hello,

Perhaps the attached PDF will tell you more about the use of an oscilloscope.
Pages 44 and 45 tell you about the probe compensation.

Bertus
 

Attachments

  • XYZ_of_oscilloscopes.pdf
    2.6 MB · Views: 0
Top