tektronix 2235a scope switch replacement

i bought a tektronix scope from ebay "not working use fro parts" I got for $50 dollars. When I got the only work on it was leds and no trace. I download the service manual and followed the flow chart. I started when no trace part. It told to press find the beam button and so I did. What luck it had a trace but when adjusted the position controls and still no no trace. The next step check all the voltages and i found that all voltages was correct and nothing. Finally the last thing a did was adjust crt bias and the trace finally appeared so I calibrated. i start calibrating every thing that needed calibrate. I notice when i used both channels one trigger and the other wont and I went the selector switch form lf/hf rej to normal the switch jammed up and broke. I need a replacement switch is a 4 position level slide switch. on the parts layout the part number is s392 I think .

I need a new switch does any no where I can get one or how fix the switch.

larry