Fooling an LCD Monitor

Nov 12, 2004 7 Replies
Z

Hello, to do testing on a monitor involving its adjustments, I need to "fool" it into thinking there is a signal when there is none. It refuses to start up without a signal, and immediately goes into suspend when the power button is pressed. Is there a pin I could apply power to or something that would give it a "signal". I don't care for test patterns, etc.



I have seen some VGA "test" schematics using PICs, etc. But I'm sure there could be a way into just "fool" it so it would at least stay on.


-Zach


Vote
Twitter Facebook LinkedIn
C

to

power

Why not just connect it to a PC?

Vote
Twitter Facebook LinkedIn
A

Most that I have seen require an active signal source to switch on, other than having it connected to an operational pc or laptop, the other suggestion would be commercial testing equipment such as produced by Sencor Corp. <

Vote
Twitter Facebook LinkedIn
B

to

power

It would depend on just what the monitor considers an "active signal" from the standpoint of its power-savings features. Most out there in the field right now will still be relying on the old VESA "DPMS" system, which simply requires that you have sync signals applied to the sync inputs that are within the recognized frequency range. A roughly 10% duty cycle (10% high) TTL-level signal of over

10 kHz applied to the horizontal sync input, plus something similar in the low 10's of Hz applied to the vertical, will generally suffice. But it very likely IS going to be easier just to find a PC somewhere and use that.

Bob M.

Vote
Twitter Facebook LinkedIn
Z

Yes, it would be easier by connecting it to a PC, but am not willing to do that in this situation (testing for project). I do see the fault in my thinking that every monitor is different and will turn on in different circumstances. I have seen schematics for simple VGA test-bar generators that use the PIC microcontroller and I will probably end up using that. Thanks for the input.

-Zach

that

there

Vote
Twitter Facebook LinkedIn
J

The monitor will require the proper sync pulses to be active. At must have a scan reference, or there will be no full start-up. This is the way that they are designed.

Invest in a small monitor test generator, or use a PC to run it.

--

Jerry G. ======

Vote
Twitter Facebook LinkedIn
A

Better idea:- program a PIC 12C508 or similar to generate the two waveforms.

This has the advantage that its relatively cheap (47p) and you can use this for a number of other purposes such as testing VCR's.

-A

Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required