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Hi all. I just wanted to post this repair journey of mine on here in case anyone's interested in learning or providing tips.
B sweep should render on 'alt' and 'b delay' mode always (as long as trigger mode on scope is set to auto). It is not displaying at all. Even with the b sweep intensity adjusted and trace sep altered.
Also, on 'A int B' there should be a bright area on top of a section of the A sweep as you move the delay time multiplier. That bright spot isnt appearing!
What I know so far:
A sweep circuit uses a constant current (using an IC) through a cap to create a sawtooth voltage. This is the exact voltage required for the x axis electromagnet to deflect the electron beam across the screen.
I've read the circuit description below to gain a further idea how the sweep circuit works, but I admit its a bit beyond me. I refered the manual to 'Google Gemini' to see if it could help me with a head start. It suggested the following:
Since I see no bright spot, I queried this a little further
From its output it sounds like the Q24 - Q26 forms a comparator comprised of transistors. The comparator compares the A sweep ramp voltage with the time delay multiplier voltage and when they cross the comparator changes its output state (from high to low or low to high) which is then fed into IC8.
If the comparitar fails, it will never recieve a trigger to let it know the time delay voltage has been reached. But of course, it could also be that the IC8 is faulty and is not outputting the correct result to to internal failure.
I'll have a poke around at this but would be interested to know if anyone had any suggestions. For now I think I'll check if the output of the comparator (input of IC8) is changing as I move the time multiplier to see if it changes.
This was the circuit description from the schematic:
B sweep should render on 'alt' and 'b delay' mode always (as long as trigger mode on scope is set to auto). It is not displaying at all. Even with the b sweep intensity adjusted and trace sep altered.
Also, on 'A int B' there should be a bright area on top of a section of the A sweep as you move the delay time multiplier. That bright spot isnt appearing!
What I know so far:
A sweep circuit uses a constant current (using an IC) through a cap to create a sawtooth voltage. This is the exact voltage required for the x axis electromagnet to deflect the electron beam across the screen.
I've read the circuit description below to gain a further idea how the sweep circuit works, but I admit its a bit beyond me. I refered the manual to 'Google Gemini' to see if it could help me with a head start. It suggested the following:
Since I see no bright spot, I queried this a little further
From its output it sounds like the Q24 - Q26 forms a comparator comprised of transistors. The comparator compares the A sweep ramp voltage with the time delay multiplier voltage and when they cross the comparator changes its output state (from high to low or low to high) which is then fed into IC8.
If the comparitar fails, it will never recieve a trigger to let it know the time delay voltage has been reached. But of course, it could also be that the IC8 is faulty and is not outputting the correct result to to internal failure.
I'll have a poke around at this but would be interested to know if anyone had any suggestions. For now I think I'll check if the output of the comparator (input of IC8) is changing as I move the time multiplier to see if it changes.
This was the circuit description from the schematic:
