Good Evening I have a tektronix 2225 oscilloscope that I have not used for a number of years. I needed it to measure the output from a 26mhz oscillator but I cannot see a sensible waveform. It just looks like a blurr. The waveform for the 1mhz test point can be held still with a little fine tuning but any higher frequency cannot be displayed properly. The trigger LED only comes on briefly on the 1mhz test point on higher frequency the trigger LED does no come on at all. Does anyone have any ideas on where to look on the pc board for the trigger fault. Kind Regards