Basically a DVD player has three main units which work
together in harmony as shown in the figure below.
We have the power board which is usually S.M.P.S but in the
older ones they used to have special types of transformers with many output to
supply to the other circuits.
Next to the power board we have the Loader which houses the
pickup and then the Decoder (electronics board) all interconnected by use of
wires (conductors) and ribbon connectors.
You can relate the actual units in the picture below, please
note that the placement of these units varies with different models.
Power supply
Currently most of the DVD players in the market are using
switch mode power supply (S.M.P.S)
One common thing with all the switch mode power supply is
that they have the primary side (HOT) and the secondary side (COLD)
The primary side includes all components from the power
supply input to the input of chopper transformer down through the middle of the
Opto-isolator.
The secondary side includes the output of the chopper
transformer, secondary rectifier diodes, and the secondary filter capacitors
for each line.
When doing voltage testing on DVD power supply, be sure to
use the main capacitor negative pin as your ground when testing the primary
side and on the secondary side use one of the Ground pin on the connector
output or negative pin of any filter capacitor on the secondary side.
Also note that the opto-isolator has two legs on the primary
side of the supply and two legs on the secondary side.
To test for voltage on this I.C be sure to use the correct
ground.
see you in the next class
Thank you so much Mr Mndaka Humphrey.
ReplyDeleteThanks and welcome Sir Joseph,
DeleteRegards Humphrey