I was working on 2230 which has power supply failure.
Changing the main bridge rectifiers CR901... CR904, Q9070 and Cr907 restored the power supply. The scope power ons with an issue CDT issue CDT value changes from 73 to 77 during different sessions of power on.
After pushing the one of the menu scrolling key CDT goes off.
I have following display issue:
1. No trace
2. Readout tex for volt/div and sec/div display.
3. Intensity and focus works
4. Sec/div switch in A mod doesn't work.
I can see only 50m 5ns and. 2s changing the position of switch.
5. Horizontal position switch works but only for half portion of the screen.
What I did so far.
1 since there is no trace just a dot I started to
Look for horizontal section.
2 looked for ramp signal at waveform 24 and 29 but I could not see any just a dc offset.
3 decided to clean the sec/div switch so according to the instruction I pulled out A4 board which contains sec/div switch. In the A4 boaed I found strange connection. Collectors of q742 and q732 are tied together and connected to A sweep input of U760 while B sweep input is left floating.
I will be thankful if some one in this forum suggest on this issue and guide me to resolve the issue of my scope.
Thanks
Saroj
