Lines and clicking sound at low brightness -- Nanao MS8-29FA
Posted: October 3rd, 2020, 3:26 pm
Hi,
I had an issue with horizontal hold on my astro city.
I took it apart and figured out cap C911 of the MS8-29 chassis was dead. So i bought a set of replacement caps and recapped everything [besides C560, C561, C521 (330uF 16V instead of the referenced 33uF 16V), C446 (33uF 16V non polarized) and the huge 1000uF 180V cap]
I also resoldered some cold joints here and there.
I was rather surprised when recapping because all new caps (rubycon -55°C +105°C) showed a smaller capacitance (within tolerance) than the nominal value. On the other hand, except for C911 which was dead, each cap I took off my chassis was overshooting the nominal value (within tolerance). I took care to measure the value of every cap I soldered and i double-checked their polarity.
Even though the connexions were all sound and solid, it took several shots for the screen to turn on.
But then when it did... To my great deception, here are the results:
So i get Horizontal or Vertical white lines on top of my image;
The image is unstable and a there is a loud repeated clicking sound if the brightness of the image is too low.
I tried different pcbs and they all undergo the same problem.
To conclude on a positive note: replacing C911 solved the H-Hold issue
Do you guys have any idea what could be responsible? Thanks for the help
EDIT: Changing caps messes up with the screen and focus adjustments on the flyback. IT WORKS NOW! Thank y'all!
I had an issue with horizontal hold on my astro city.
I took it apart and figured out cap C911 of the MS8-29 chassis was dead. So i bought a set of replacement caps and recapped everything [besides C560, C561, C521 (330uF 16V instead of the referenced 33uF 16V), C446 (33uF 16V non polarized) and the huge 1000uF 180V cap]
I also resoldered some cold joints here and there.
I was rather surprised when recapping because all new caps (rubycon -55°C +105°C) showed a smaller capacitance (within tolerance) than the nominal value. On the other hand, except for C911 which was dead, each cap I took off my chassis was overshooting the nominal value (within tolerance). I took care to measure the value of every cap I soldered and i double-checked their polarity.
Even though the connexions were all sound and solid, it took several shots for the screen to turn on.
But then when it did... To my great deception, here are the results:
So i get Horizontal or Vertical white lines on top of my image;
The image is unstable and a there is a loud repeated clicking sound if the brightness of the image is too low.
I tried different pcbs and they all undergo the same problem.
To conclude on a positive note: replacing C911 solved the H-Hold issue
Do you guys have any idea what could be responsible? Thanks for the help
EDIT: Changing caps messes up with the screen and focus adjustments on the flyback. IT WORKS NOW! Thank y'all!