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chameleon789 • Jul 23, 2008

Need some advice on power adapter, and quickly!

I'm not an electrical engineer, but I could really use the opinion of someone who knows what they're talking about - sorry for asking here, but this is the only place I could find and I feel I can trust you guys judgement. If you could help I'd really appreciate it.

I recently bought a new monitor for my server from ebay - the only thing it didn't come with was the original power adapter, but I had a universal ac/dc adapter lying around which I assumed would work. Of course, the monitor arrived, and the adapter didn't work. FAIL. Well, it kind of did - the monitor would cycle power, turning on for a split second before turning off for 3-4, and then repeating the cycle indefinately.

Now, I know for certain that the output of my universal adapter matches that of the official one - 12V DC, 3A. The universal supply is unregulated, although I'm not sure if that makes a huge difference - I'm assuming it doesn't.

I don't know much about this area of electronics - but maybe you guys have some idea of what the power cycling problem could be indicative of (be it the adapter or a component of the monitor)? I'm trying to assertain whether it'd be worth forking out for the proper adapter or just admitting defeat and returning it - the thing only has a 7 day warranty, but I'd rather keep it as it was a bargain... would there be any other difference between my universal adapter and the official one that could make the difference between a working monitor and a serious problem like this?
hey fisrt of all make sure your monitor is fine,why dont ya try a sabilzer as its source,connect the adapter therr,then check,as for online purchase its always risky!!!
just2rock • Jul 24, 2008
you can get assure of your stabilized monitor only when you see absolutely no Vibration on the screen ,due to frequency alterations.If you see the same problem persists even after you attach the Adapter module ,just check that the module has the marked safety standard on it along with the corresponding voltage regulation knob having the superscribed Range written on it.
chameleon789 • Jul 25, 2008
I don't have a stabilizer at hand, unfortunately - I don't know anything about this apart from what I've learned from google, but you're saying that a stabilizer would make up for the fact the power adapter I'm using is unregulated?

So, having an unregulated adapter as opposed to an adapter with a voltage regulator could cause a problem like this..? If so, could buying a regulated adapter @ 12VDC 3A solve the problem? *Also (this question proves how little I know), would it be ok/wise/safe to use an adapter with a slightly higher amperage than 3A, say, 4.8A?
you can try it buddy, but still i wont suggest you for long time ur monitor ok!!!
1. Original OEM adapters are ,matched for Voltage and Current ratings of the equipment manufacturer. it may not be correct to use anything other than the OEM adapter.
2. Other adapters available off the shelf only carry ratings on the panel!!!!! They may not supply the required power. ie., the printed ratings may be far from the required thing.
3. Some Monitors reset if there is serious ripple on the DC line. This could happen due to poor regulation, underrated Transformer/switching devices, sub-standard components etc.,
4. The Monitor seems like it is resetting itself due to insufficient Current on load and the resultant voltage drop.

This may prove to be disastrous to the monitor.

5. The power rating of the adapter/Power supply doesnt matter if it is greater then the needed value. Infact , it is desirable that it is over-rated.

Meaning: you can use even a 100A adapter provided the Voltage is 12v and does NOT vary greater than +/- 5%.
The load decides the current at the specified Voltage and will draw just that much. The maximum current rating does not matter here; only the minimum does !!

Let me know the Monitor specs - model no. manuf. etc.,........

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