Power Surge Causes HDMI failure?

shooter mcgavin

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Hi guys, I had what I believe to be a power surge and the HDMI output on my Denon AVR-E300 and the HDMI input on my LG LCD TV no longer work. I tested it with other inputs on the TV with various cables and also tried on a monitor to no avail. So here's what happened:

I was playing a game on my HTPC when the display started to cut out. I ignored it the first time or two but then it became very frequent and then cut out completely. I opened the PC and heard a buzzing noise. I first thought it was the graphics card but then realized that the power supply was the culprit. So I powered down the computer and it continued to buzz. I unplugged it but I still heard more buzzing. That's when I discovered that the TV mounted on the wall was also buzzing. I unplugged the surge protector that all of this was plugged into and went to investigate. Then I heard more buzzing in the kitchen and heard the microwave buzzing and the fluorescent lights in the garage were pulsing.

I got my multimeter and measured the voltage at the wall. It looked a little above normal (~124 V). A while later I measured the incoming voltage to my house and saw that it was about 126 V on one of the leads. 126 V is the level of concern for them, ±5% of 120 V. So I called the power company out but by the time they arrived it was lower. They said it was potentially a problem on their end but would not admit fault in their report. Something about possible ground amps. They told me to call back again if it happened later. That was Sunday and it hasn't happened again.

I am planning on taking the receiver in tomorrow for warranty service. The TV is out of warranty but functions fine, minus one HDMI port. I only use one input because I use the receiver for switching video sources. I believe everything else is fine.

So my questions are:
1. Does this seem like a surge from the power company? Or an electrical problem from within my house?
2. Is the failure of the HDMI ports caused by one the devices malfunctioning and then passing a high voltage to the other connected one? e.g. The TV producing a high voltage via HDMI and blowing the HDMI board in the receiver.
3. What do I do to prevent this in the future? UPS? The surge protector I had installed (Belkin) did not stop this from happening.
4. How likely is it to make a successful claim on a surge protector guarantee?
5. Should I do anything with the computer to make sure all is functioning properly? It seems fine but I don't use every feature of the motherboard.

I appreciate any responses and for taking the time to read my post. Thanks!
 

westom

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Ideal voltage for all electronics is even above 126 VAC. Marginal for an AC utility. But well within ideal numbers for any electronics.

However, other anomalies could exist that might also explain buzzing. Did you physically inspect all safety grounds to confirma direct connection to a bus bar inside the main breaker box?

Read spec numbers printed on each surge protector box. Its let-through voltage is 330 volts. That means it does absolutely nothing until 120 volt mains exceed 330 volts. A Belkin also does not claim to protect from other and destructive surges. Also read fine print exemptions in its warranty.

Excessive voltage variations are easily identified using an incandescent bulb. Simply connect to same power provided to TV and interconnected appliances. That bulb should not change intensity. Normal voltage for any electronics is even when that bulb brightens by 30%. An incandescent bulb is an easiest and fastest way to monitor for abnormal voltages.

Meanwhile, is a computer OK? It may boot and execute just fine even though its power system is defective. Identify its power system as good or compromised by requesting instructiions for using the meter and one full minute of labor. Resulting numbers from six wires mean others who better know this stuff can report something useful.
 

shooter mcgavin

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Thanks for the reply. I know that 126 V isn't ridiculously high, but this was measured a couple of hours after the buzzing had stopped. I'm not sure if it would have been much higher if I had measured at that moment.

I have not inspected the ground connections in the breaker box. Are you just saying to make sure that each breaker has an attached earth ground? I can do this tomorrow during the daylight hours (panel is outside). I have tested each outlet with an outlet tester and no errors come up. I will also do what you say with an incandescent bulb, especially if the problem reappears.

The belkin surge protector I have is this one:
http://www.belkin.com/us/p/P-BE112230-08/
Not sure if what you are saying applies to this one.

And out of nowhere last night the second HDMI input on my TV went out, this time there was no buzzing or anything. I only have 3 inputs and when I switched to the third, the TV rebooted several times before finally working. I am worried that it will also break and then I will have no way to input via HDMI. Does this sound like the TV is failing?

Thanks again for your help.
 

westom

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High voltage and a surge are two completely different anomalies. As defined by numbers. An excessively high voltage might be 180 volts on 120 volt wires. A Belkin will completely ignore that or just slowly degrade to uselessness.

Another anomaly is about earthing a surge. Not earthing a circuit breaker or appliance. A Belkin has no earth ground. It only has something completely different - safety ground.

Surge protection is about hundreds of thousands of joules dissipating harmlessly outside - in earth. That means no surge current is anywhere inside a building. That may have created the original problem. But that is not blowing out HDMI ports.

So, stick to one problem. HDMI ports are not as robust as other connections. Apparently you have a harmful voltage difference between that TV and its connected appliance. A voltage that can be explained by numerous other defects. For example, is an HDMI connection between two devices that do not share a common power receptacle? That should not cause damage if some other defect did not also exist. But we know this much. Some excessive current is passing though HDMI cables. Why does a voltage difference exist between that TV and attached appliance? Long before considering a solution, first that problem must be defined.

Even a defective safety ground (not earth ground) might explain it. A list of possible reasons why are quite long; too many to list here. But most likely suspects include household wiring defect, a defect inside the TV or HDMI attached appliance, or some third device that is electrically defective. All we know is an excessive current through that HDMI connection is creating a high and destructive voltage on your HDMI ports. We do not even know which wire in the HDMI cable. Magic plug-in devices can only (and sometimes not) cure symptoms. First find a defect. Fixing it comes later.

Another possible useful fact. Your meter should not measure any AC voltages between each contact inside the HDMI ports (TV or attached appliance) and safety ground, chassis ground, or any electrically conductive parts of all other nearby appliances. A detected AC voltage is an example of finding the problem. Fixing it comes later.

Obviously you also want surge protection that actually does protection. But that is another topic unrelated to what what is now blowing out multiple HDMI ports. Lack of surge protection might explain why a defect was originally created. But for now, find a defect that is blowing out HDMI ports. Much later, move on to another and different problem: apparently non-existent surge protection especially if you thought a Belkin actually did that.
 

shooter mcgavin

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Thanks for the input westom. Sorry I have been out of town for awhile and I haven't been able to look at these issues. My receiver is still being worked on under warranty. My TV eventually quit on me and I figured out that I had to replace the main board. I was able to do this for fairly cheap thankfully.

From what I have read it seems that electronics will do pretty funny stuff when they receive a high overvoltage, like damage boards. The surge protectors do not protect from this as the clamping voltage is 330 V. I haven't had a repeat event like this since then and because it was a whole house occurrence (everything was buzzing and light bulbs were pulsing), it seems likely that I was getting excessive voltage from the utility. So line interactive UPS would be able to protect me from this in the future from what I understand.

If I am totally off base or if anyone thinks that it would be a really good idea that I get an electrician out to look at my household wiring, please let me know. Otherwise, I'm going to wait for UPS to go on sale an get a couple for my home theater setup and my gaming rig.
 

westom

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Assume the destructive surge current creates a 5000 volt spike on a hot (black) wire. A 330 volt protector means a 4670 volt spike is now connected to electronics neutral (white) and safety ground (green) wires. So a surge now has more wires to hunt for earth destructively via electronics. Where is this protection?

Same applies to an interactive UPS. Similar or better protection already exists inside electronic power supplies. If a surge can overwhelm protection in electronics, then it also overwhelms protection inside any interactive UPS. Again, if a surge current is incoming to that UPS, then same current is also outgoing into and through attached electronics - at the same time. Where is this protection?

Read interactive UPS specification numbers. Where is one that actually claims to protect from the above destructive surge? Does not exist.. It claims protection for surges that typically do not damage electronics.

Destructive surges can be hundreds of thousands of joules. How many joules did that adjacent protector claim to absorb? Hundreds? A thousand? IOW it only claims to protect from near zero surges. View manufacturer specificatons for an interactive UPS. Joules numbers are typically less - meaning even less protection. Per spec numbers, an adjacent protector or UPS provide similar and near zero protection.

Protection is always about where hundreds of thousands of joules harmlessly dissipate. Facilities that cannot have damage spend tens of times less money on a solution that makes even direct lightning strikes irrelevant. This 'whole house' solution means a current that might otherwise create 5000 volts does not even enter a building. Effective because it uses the same earth ground solution described earlier. And costs about $1 per protected appliance. An earthing connection that does not exist with adjacent protectors or interactive UPS.

Voltage variations made irrelevant by an interactive UPS are also made irrelevant by what already exists inside all electronics. Protection that must be so robust as to make irrelevant 'dirty' power from a UPS in battery backup mode.

How 'dirty'? This 120 volt UPS in battery backup mode outputs 200 volt square waves with a spike of up to 270 volts. Since all electronics are required to be robust, then this typically 'dirty' UPS power is not harmful to electronics.

 

shooter mcgavin

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Ok...then what should I do in the future? Should I take any action? Is whole home protection what you use? Do you use anything on top of that?
 

rgarteteach

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good, That means it does absolutely nothing until 120 volt mains exceed 330 volts. A Belkin also does not claim to protect from other and destructive surges. Also read fine print exemptions in its warranty.

 

shooter mcgavin

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I'm still not clear on what I am supposed to do in the future. Just deal with all of my electronics getting damaged? Are there any solutions to my problem?
 
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