Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

More up-date for this monitor:

1) the front push button is completely out of services now, the blue LED lite up as soon as the power is supplied to the monitor; if PC signal connected to the interface board, the monitor works like normal, if no PC signal, the blue LED turns into yellow. In either way, pushing the PW button does absolutely nothing.

2) hooking up a multimeter to these connector pins between the power board and the interface board shows that the bus voltage +5 and +3.3V...

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

After overnight cooling, the monitor start to response to the front power push button again, this indicates that the melfunctioning is reversible event(s)?

U5 has 3.3 V and 2.51V and is reasonably stable.

The replacements are Rubycon SL360.

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

Here is the update, after working for about 2 hours, the monitor can not be turned off by the front push button again.

It seems that there are some components that is fine when everything is not hot, but start melfunctionion after warmed up. All the button on the front panel is not functioning.

Will try again after everything cooled down to test the above hypothesis.

Any ideas and suggestions are highly appreciated.

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

Thanks everyone for the helpful suggestions and insightfulness.

All the Elite and Lelons' capacitors have been replaced ( total 39) on both the power board and the logic board. The monitor is working again and , hopefully, it will keep working for a long time.

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

Yes, there are tow capacitors on the board with all the push button switches.

I will replace all the Elite and Lelon capacitors.

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

Here is the other two boards, they look OK.

Just checked the power push button sw306 and it functions normal.

All bus voltage are there, +5, +3.5, +/-5, +/-16 V....

Re: BenQ Q7C3 (FP767Ver2) can not be turned off by the front push button

Here is goes, let me know if it would be helpful to focus on any particular part on the board.

Thanks....

BenQ 17" LCD, Model: Q7C3, made on October 2004 Rev:BBD, Part #FP767 Ver2

This monitor started to develop problem with the front push button power switch about a month ago. Initially, it can not be turned on by pushing the power switch on the front panel, however, after swapping the power cord and other stuff, it can be turned on by the front power switch and worked for about a week.

After it refuse to turn itself on again, it was taken apart, all the components, both on the power supply board and the signal board, looks OK. There are no any burned parts or bulged...