Lab-Volt 791 Oscilloscope

[tomloader]

I have an old Lab-Volt 791 Oscilloscope that I purchased several years ago at a garage sale. It worked for a few months, but eventually the trace stopped scrolling horizontally, so I just have a dot. I can change the location of the dot with the horizontal and vertical controls, so assume that the display is working ok. I have had a look inside, and can not see anything suspicious looking, but I am no electronics genius and I wouldn't know where to start looking.

I have access to a nice digital fluke meter, so I could test the Lab-volt, if I knew what to test and what to look for.

If anyone on this forum has any experience with this type of scope I'd really appreciate some suggestions.

Cheers.

 

[kchriste]

Assuming all the controls are set correctly.
If you put in a signal and all you get is a vertical line, then it sounds like the horizontal sweep oscillator/circuit is defective. The sweep trigger circuit could also be defective or set wrong.

 

[bountyhunter]

I can change the location of the dot with the horizontal and vertical controls

That means the horizontal and vertical output drivers are working, but the horizontal sweep is not working.