Hi!
I just bought an old TEK 422 (1965 - 1975) from a 82 year old retired engineer that used to work at "Elektrisk Bureau".
http://en.wikipedia.org/wiki/Elektrisk_BureauChannel 2 is not working. I can only see a faint lit-up ghost passing the screen when I turn the INTENSITY knob all the way right. This ghost looks just like channel 1 when I purposely turn CH1 vertical POSITION knob all the way, either far left or far right (off screen). Because the similar looks between CH1 when deflected off-screen and CH-2, I believe that channel 2 is deflected off-screen as well. (the scope has no beam finder)
This situation is well described in the Tektronix publication: "Troubleshooting Your Oscilloscope" (Getting down to basics) on page 47. The publication can be found here:
http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf . My problem is that I just can't recognise which section of the scope, the low-res image is regarding.
I want to "common mode" "the stages", but I dont know which section of the scope circuit the illustration "FIGURE 1" on page 47 or "FIGURE 2" on page 48 is taken from. I would be very happy if someone could please tell me which circuit this figure 1 or 2 is taken from. I need to figure out where to apply a "clip lead to short the signal input pins of the amplifier stage" (quote from troubleshooting manual page 48 regarding "IC amplifiers" and not specifically "Push-Pull" amplifiers).
Again: which "stages" in what section of the scope are to be "common moded"? What points in the circuit and on which board do I connect to see if the beam is pulled onto the screen again?
Maybe this block diagram is the one: Instruction Manual for the 422 (
http://w140.com/tek_422.pdf ): Block diagram page 169/170 "<4> VERTICAL SWITCHING AND OUTPUT AMPLIFIER" with symmetric looking transistor pair Q224 and Q234? Maybe I should common mode the Bases of these transistors?
nixxon