19-07-2023, 01:05 AM
(This post was last modified: 19-07-2023, 01:08 AM by LENINGRAD T2.)
I connected the oscilloscope to the anode 20P1. I got a waveform with a peak and a short glitch. I assumed it corresponded to the vertical bar on the screen on the left. The next tests were to check what influences this nightmare image from the oscilloscope.
- once again I replaced all R/C elements with nominal and slightly different values - zero effect
- I replaced the 20P1 lamp - zero effect
- I heated the core of the line transformer - zero effect
- I checked the voltages supplying the deflection system - the values were correct
- I installed a damping system with different R/C values in parallel to the scanning coils - zero effect
- I tested the R/C elements in selected points of the circuit - zero effect
- I disconnected the EY51 - zero effect - disconnected the scanning coils - zero effect
At this point, only the components connected to the G2 remained for testing. I have already found that changing the capacitance of C2 affects the width of the noise on the screen. Let me just remind you that the elements C2, P1, C1, R1 were factory-fitted to my TV, but they are not present in the original diagram.
I decided to restore the circuit to the original version. I removed C2 and P1. I adjusted the value to R66 and the nightmare bar on the screen disappeared. The picture is still not perfect. There is a slight linearity problem. The oscilloscope image from the V15 anode is now correct.
- once again I replaced all R/C elements with nominal and slightly different values - zero effect
- I replaced the 20P1 lamp - zero effect
- I heated the core of the line transformer - zero effect
- I checked the voltages supplying the deflection system - the values were correct
- I installed a damping system with different R/C values in parallel to the scanning coils - zero effect
- I tested the R/C elements in selected points of the circuit - zero effect
- I disconnected the EY51 - zero effect - disconnected the scanning coils - zero effect
At this point, only the components connected to the G2 remained for testing. I have already found that changing the capacitance of C2 affects the width of the noise on the screen. Let me just remind you that the elements C2, P1, C1, R1 were factory-fitted to my TV, but they are not present in the original diagram.
I decided to restore the circuit to the original version. I removed C2 and P1. I adjusted the value to R66 and the nightmare bar on the screen disappeared. The picture is still not perfect. There is a slight linearity problem. The oscilloscope image from the V15 anode is now correct.
