Packard Bell Maestro 221W

[jm20101]

Hello Members of Badcaps,

Recently, I have bought this screen as defective. It is working for about 3 seconds and then it shut off (light keeps burning).
And if I turn the brightness at low, the screen keeps working. I have attached a picture of the two boards.
Any capacitors recommend to replace? There is also a high pitched noise from the power board.

Thanks for the help,
Joris

[budm]

Re: Packard Bell Maestro 221W

I would recommending replacing all 9 lytics caps (the big one is probably OK) on the power supply board.

[lexwalker]

Re: Packard Bell Maestro 221W

Hello Members of Badcaps,

Recently, I have bought this screen as defective. It is working for about 3 seconds and then it shut off (light keeps burning).
And if I turn the brightness at low, the screen keeps working. I have attached a picture of the two boards.
Any capacitors recommend to replace? There is also a high pitched noise from the power board.

Thanks for the help,Joris

That high pitch noise can be caused by badcaps. As earlier mentioned, just replace all the electrolytic capacitors on that board. Also look around the board for dry/cold solder joints especially the inverter section (such as the power transistors, transformer and lamp connectors)...

[jm20101]

Re: Packard Bell Maestro 221W

Thanks for the help but after replacing all the electrolytic capacitors (include the big 100uF) the problem still occurs. The high pitched noise is still there but only in standby mode.

[selldoor]

Re: Packard Bell Maestro 221W

You will have to pinpoint where the noise is from - make a listening tube from a rolled up
cereal packet or similar.

Do the lamps stay lit now?

Can you swap over the lamp leads and see if the noise moves.
Have you a spare tube or can you make up a bulb as per budm
https://www.badcaps.net/forum/showth...er+testing+cfl

[jm20101]

Re: Packard Bell Maestro 221W

If I switch the lamp lit connections, the problem still occurs.
The noise is coming from a small capacitor left under to the yellow transformer (222K 1KV).
Can this capacitor be the problem? And the value is 2200pF?

[selldoor]

Re: Packard Bell Maestro 221W

May be a symptom rather than cause - yes it is 2200pF 1KV

Can you post a picture of the bottom of the board. It needs to be really clear so
do it it in halves or quarters if it helps to get it clearer.

I think it may still be a problem with the bulbs - another test is try one bulb at a time
and see if it flashes ( this is only a test for totally broken bulb which will not flash at all
they will not stay lit but will jsut flash if not totally broken )

When the bulbs are not taking any power that can cause the squeal.

[lexwalker]

Re: Packard Bell Maestro 221W

Thanks for the help but after replacing all the electrolytic capacitors (include the big 100uF) the problem still occurs.

What were the brand and series of capacitors used? Have you checked for dry/cracked solder joints?

The high pitched noise is still there but only in standby mode.

If I switch the lamp lit connections, the problem still occurs.
The noise is coming from a small capacitor left under to the yellow transformer (222K 1KV).
Can this capacitor be the problem? And the value is 2200pF?

That's 2200pF or 2.2nF, with 1kV voltage rating. The symptom sounds familiar, reminds me of those HP w2228h (can google for this monitor's buzzing/hissing issues, plenty of them). A "singing" capacitor at the snubber section. Usually a lone standing ceramic disc type. Its called microphonics, and usually occurs with Class 2 ceramics (especially those cheap and poorly contructed ones). You can replace this with a better ceramic capacitor (such as those Murata safety high voltage ones), or with a metallised film capacitor with the same ratings (higher voltage rating recommended). As for the lamp going off, check the MOSFETs or transistors driving the inverter transformers. Also check the resistance of the inverter transformer secondary windings. A bad inverter tranformer and/or a failing MOSFET can cause lamp shutdowns...