LCD Monitor: Viewsonic VA520 on the Bench

[[email protected]]

Hi.

I'm now the proud owner of an unused LCD monitor that won't power up.
After doing some research, one finds that -- in the case of Viewsonics
-- the problem often gets traced to a faulty power supply.

After prying open the 12v, 3.8amp box, it appeared that the three-
prong plug socket seemed not to be entirely connected. If this
breakage didn't occur during my dissassembly of the unit, then it was
probably the reason why my new LCD monitor wasn't working.

So anyway, to cut-to-the-chase, my question is:

Will a replacement 12v power supply with more than 3.8 amps (with +
center pole +) have any notieable effect on the monitor? Most of the
used 12v adapters I've found tend to be in the range of 750mA, or as
low as 1amp, but nothing with the exact original amperage.

 

[Jerry G.]

You will need at least a 4 amp rated regulated 12 Volt power supply.
These are commercialy available from most electronics parts suppliers.
They come on a circuit board. You can mount it in your own case and
use the original Viewsonic wire end. If you do a google search for 12
volt reglated power supplies you should find many of these.

Just a suggestion, is that most of the failures in these supplies are
the electrolytic caps. Sometimes the power devices such as the output
IC and or some support components can fail, but this is not often.


Jerry G.

 

[[email protected]]

Thanks for the pointer.

Just as an update, I found a second-hand Sprint AC adapter with 3A,
12v, and swapped in the original 5.5mm plug for a test. And yes, the
monitor does now power up and show input.

However, with this adapter, the screen blinks on and off
intermittently. Obviously there is some difference here beteen a class
2 adapter and a power supply box.