how do I adjust Horizontal Positioning on my scope?

[solder_boy132]

I calibrated the scope with the horizontal time base on my Tektronix 2235 oscilloscope, but when I powered it on again, the trace was shifted ti the left. I used the horizontal positioning knob to try and move it to the center, but the trace was still there. I probably read the service manual wrong and trimmed the wrong pot. I looked in the manual for the pot used to move the trace, but with no luck. So this is why i'm posting this.