I just bought a GW Instek GOS-6112 at a reduced price on the basis that it had only been tested by powering on, which showed a flat trace.
Unfortunately it only shows a flat trace on both channels when the probes are connected to the test signal, using the recommended settings from the user manual (which I downloaded). I have tried adjusting all settings through all ranges (although almost certainly not all combinations!).
I thought it might be that the test signal was not working, but my digital scope can see the wave form from the 6112 test connection.
The BNC socket for channel 1 seemed loose, so I took it apart and found the internal connection to channel 1 had broken, probably due to the movement. I tightened it up, resoldered the connection and checked the resistance between the BNC and the board, which now matches channel two (approx 10 ohms).
However the test signal still just shows a flat line. I feel like I'm either missing something obvious or perhaps there is some particular area I should look in when the controls all work but the line is always flat on both channels? Since my minor repair I have not reassembled the scope and am testing it with the input board resting on the upside down scope.
I am a newbie in electronic repair, though I hope to learn. I have previously used a scope to check for interference on comms lines, as I am a software developer "by trade". I liked the look of a simple analogue scope for learning more about repair work - though I wasn't planning to start with the scope itself!
The scope seems in great condition inside and fair condition outside ... apart from the minor issue of not working!
Any suggestions of where I might start or if I may have missed something simple would be appreciated - thanks!