LCD monitor cannot turn on, already replaced blown capacitors

[meganco]

First of all, thanks for taking the time to help!

The monitor is an Asus VH238H. I leave the monitor on almost always (which probably is a reason why it died), but it stopped working right after I turned it off for maybe 2-3 minutes, then tried to turn it back on, resulting in just a black screen. Note that it can still turn on and stay on, but nothing appears on the screen. I'm not sure if this is important because this will change later on.

I eventually opened it up and found one blown capacitor, which I replaced. When I tried to power it on again, the monitor now makes a faint, short squeak then powers off and stays off until I try to power it on again.

Did I maybe mess something else up during the process of replacing the single capacitor to cause this change? All of the other capacitors have flat, indented tops, could they still have gone bad? If it's not the capacitors, what should be my next step in trying to fix it?

 

[Harvey]

I'll assume you installed the new cap with polartiy (+/-) oriented the same way as the old part. I'll also guess that your monitor is out of warranty. (They always fail just after the warranty is up.)

Old electrolytic caps (the big cans) can be bad without showing external signs such as swelling at the top or leakage around the bottom. If one is bad, others also may not be working, or at least working to full spec.

These caps are used to filter the power supply to the rest of the circuit, which suggests two other possiblities:

1. A blown cap may cause failure of one or more of the chips in the monitor.

2. It may also indicate that something in the power supply circuitry, itself, has failed. If a regulator circuit failed, it may allow excessively high voltage to reach one of the other components in the system.

If you're a tech, or you have a good friend who is, and you have a service manual, you may be able to determine the problem and fix it. If not, you'll probably need to take it to a good repair tech.

The biggest problem is that, if it's a major problem, the cost of repairing it could be close to the price of replacing it.

Hope that helps. Good luck.

 

[meganco]

You're correct, the warranty expired just shy of 3 months. Bleh!

Unfortunately, I'm only a Googling expert and tried to fix it myself. My only other option would be to take it to a repair shop, but I've been holding off since I might opt for just replacing it entirely.

The capacitor was installed with the correct polarity, but it sounds like my next best move should be trying to replace the rest of the capacitors to see if that will fix the issue. I don't have the tools or experience to test out any of the rest!

Thanks for your time and advice!