Oscilloscope - Tektronix 2336 YA - Strange ringing (between 100-200 MHz) problem

• Oscilloscope - Tektronix 2336 YA - Strange ringing (between 100-200 MHz) problem
  Posted by felixd on 07 Oct, 2012 20:50
• Hello.
  
  I'm seeing strange thing on my Tektronix 2336 YA. Since I've bought it oscilloscope is triggered by a pulse that is coming from "nowhere". It appears randomly in every 30s - 2 minutes.
  
  This pulse is seen on each channel (on AC/DC/GND mode), probes connected/disconnected. This pulse is also seen on probe compensation signal. This is how I've managed to record it using 2nd oscilloscope. Pulse/ ringing  frequency is between 100-200 MHz.
  
  This pulse runs trigger.
  
  I've also accidentally recorder it on below video (0:36 second)
  
  Wiertolot - Silnik EMAX GT2215
  
  I've recorder this pulse also on probe compensation signal:
  
  
  
  
  
  
  Any ideas why this pulse appears? How can it be fixed? What to check ? ;]
  
  Thanks for replaying
• #1 Reply
  Posted by Niklas on 08 Oct, 2012 00:02
• Perhaps it is not related to the oscilloscope at all. It might be something in the same building that draws a lot of power and is switched on or off periodically. Perhaps try another power outlet and see if the problem disappears?
• #2 Reply
  Posted by felixd on 08 Oct, 2012 14:18
• I've connected it to UPS.
  Same thing.
  
  My digital scope is not affected.
  Can it be dirt inside old scope + very high voltage? Maybe that's a problem.
  
• #3 Reply
  Posted by PA0PBZ on 08 Oct, 2012 18:10
• It almost looks like a burst of RF, but it seems a bit short to be useful. Any RF transmitters near that could do this?
• #4 Reply
  Posted by xygor on 08 Oct, 2012 21:35
• It looks like there might be an intermittent arc inside the scope.  Open the case, turn off the lights, look, listen.
• #5 Reply
  Posted by felixd on 08 Oct, 2012 22:19
• Quote from: xygor on 08 Oct, 2012 21:35

  It looks like there might be an intermittent arc inside the scope.  Open the case, turn off the lights, look, listen.
  

  
  I was talking yesterday with people from Poland. They told me that this might be the problem.
  I'll check that tomorrow.
• #6 Reply
  Posted by felixd on 01 Dec, 2012 16:20
• Lot of time since my last post. The problem is with arc's. I can hear them, but I'm not able to see them
  
  Today I have some time to dig inside my oscilloscope.