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Sony 19" CPD-420GS Focus changes at random

H

Homer Simpson

Jan 1, 1970
0
I have a Sony 19" Trinitron Monitor, CPD-420GS.

Here recently, the focus will change on it's own. Usually, it starts
with a "click" from the flyback side of the monitor, and then the
focus will change from mild to wild.

Had the monitor open, and checked for cold solder joints. Found none,
but resoldered some previous repairs (Q901 and Q902). Didn't find any
obvious leaking caps.

Any help appreicated.....
 
J

Jamie

Jan 1, 1970
0
Homer said:
I have a Sony 19" Trinitron Monitor, CPD-420GS.

Here recently, the focus will change on it's own. Usually, it starts
with a "click" from the flyback side of the monitor, and then the
focus will change from mild to wild.

Had the monitor open, and checked for cold solder joints. Found none,
but resoldered some previous repairs (Q901 and Q902). Didn't find any
obvious leaking caps.

Any help appreicated.....
Bad flyback ?
 
M

Meat Plow

Jan 1, 1970
0
I have a Sony 19" Trinitron Monitor, CPD-420GS.

Here recently, the focus will change on it's own. Usually, it starts
with a "click" from the flyback side of the monitor, and then the
focus will change from mild to wild.

Had the monitor open, and checked for cold solder joints. Found none,
but resoldered some previous repairs (Q901 and Q902). Didn't find any
obvious leaking caps.

Any help appreicated.....

Focus block and flyback integrated? If so, change it.
 
F

Franc Zabkar

Jan 1, 1970
0
I have a Sony 19" Trinitron Monitor, CPD-420GS.

Here recently, the focus will change on it's own. Usually, it starts
with a "click" from the flyback side of the monitor, and then the
focus will change from mild to wild.

Had the monitor open, and checked for cold solder joints. Found none,
but resoldered some previous repairs (Q901 and Q902). Didn't find any
obvious leaking caps.

Any help appreicated.....

There is a service manual at http://www.eserviceinfo.com

- Franc Zabkar
 
H

Homer Simpson

Jan 1, 1970
0
Figures... now that I dont need the manual, it's everywhere on the
net! I had to actually order the manual from Sony about 5 years
ago....

I am thinking a new FBT. The monitor sometimes will emit an audible
CLICK! and the picture will go blank for a second, then come back on.
Usually only does this once.... FBT and HOT are the original parts.
Q901 and Q902 were replaced about 5 years ago.

Every once in a while, the picture will flicker to dim, and then back.
Resoldering a few spots that looked bad and reseating the neckboard
seemed to fix this, for now.

I wonder if it is worth putting a new FBT in this thing. It's working
on 8 yrs old... that and I dont have the equipment to retune the board
for a new FBT (IIRC, the manual says you have to adjust some pot on
the board for the FBT when changed.)
 
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