View Single Post
  #2   Report Post  
Posted to sci.electronics.repair
Sebastian Voitzsch
 
Posts: n/a
Default Whining 100 Hz PHILIPS TV w vertical bars

Matti Kaki wrote:

Hello from Finland.

I have Philips TV 29PT8702 chassis: MD2.12E which whines a lot.
It has also odd phenomenon which looks like ringing or ghost.
Few vertical bars on the left and the right part of picture.

I have varnished the L.O.T. and linearity coiletc. but no help
at all. The whining comes (I'm quite sure) from L.O.T. I took
few pictures if you like to take a look of the phenomenon.

http://www.sci.fi/~oh2bio/hilipsi.jpg

I remember that I have seen this phenomenon in Barco monitor
and it was caused by bad voltage. I checked the voltages from
PWR but they were quite OK (if I haven't missed one or two).


Did you also measure the ripple on these voltages? I had a similiar error
with an older ITT tv set caused by a bad cap in the 12V-branch.

Whining on another set was caused by bad B+-cap.

I?d simply test the caps for high ESR.

HTH,
Sebastian