Oscilloscope troubleshoooting

[111]

My CRO have following problems. Can you help me?

Instead of a single straight line ( eg if it is put in GND or in any other modes ) there are 6 straight lines (even in horizontal, vertical or slope signals.) No problem with the probe.

No focusing.

How will I correct this problem?

 

[Russlk]

Are there 6 horizontal lines all the way across the face of the CRT? How far apart are they? Do you mean the focusing does not work? Does the brightness control work? What happens when you change the horizontal frequency?

 

[111]

Six parallel straight lines are only in the signal path and are placed very close to each other
When the frequency is varied it is as usual
If it is put in the transfer mode instead of focusing in a point the beam spreads out
But by adjusting ASTIG the no. of lines can be reduced to four and it cannt be reduced further
Intensity works

 

[EdwardM]

Hi

a couple of things...

can you post a picture of the screen?

what's the make and model number of the oscilloscope?

Ed

 

[Russlk]

It could be that the beam is being intensity modulated. There may be a connection on the back of the scope for intensity modulation, if there is, connect a jumper to case and see if that helps. Otherwise, you will have to open it up and trouble-shoot.