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HDMI PORTS KEEP GOING BAD

post #1 of 11
Thread Starter 
Hello,

I am having an issue that might be electrical wire issues but also sounds similar to the forum post: HDMI "OUT" PORTS KEEP GOING BAD. I will try to be concise as possible. I have an Insignia NS-42L260A13 HDTV, a Scientific Atlanta- Explorer 8300HDC cable box, and a Sony BDP-S580 Blu-Ray player. On 4 occasions within a month and a half I have had my HDMI ports go out on my cable box and TV. All the occurrences have been within seconds of major thunderstorms. Normally I would think with lightning that would be the problem. However the frequency tells me there is causality and lightning may only be the trigger.

The first time I stupidly had the equipment plugged only in a power strip. I was watching TV when the power went out really quickly and right back up again. When I turned on my TV and cable box I noticed I was receiving "no signal". I tried rebooting the cable box and still nothing but noticed a strange sound from the hard drive. The Blu-Ray worked fine and used it to test all the ports on the TV, which was fine. I called the cable company and they replaced the box.

The second time again I had all the equipment plugged into a power strip (Still haven’t learned). When I got home after a severe storm I turned on the TV to see the "no signal" again. Testing the above process again, the cable box is working but the HDMI port is out. The Blu-Ray player is working and I use it to test the TV which is also working. Again I called the cable company and they replaced the box but say we really should use a surge suppressor rather than a power strip.

The third time I had all the equipment plugged into a surge suppressor. I wasn't at home at the time but my wife tells me the power flickered a few times. After a while she decides to turn on the TV and sees "no signal". When I get home she lets me knows what happens and I test the above process again. The cable box is working but the HDMI port is out again. Again the Blu-Ray player is working and I use it to test the TV which is also working. Again I called the cable company and they replace the box. This time the cable guy tells me because of the frequency the problem might not be due to the lightning but rather a surge effect. Which makes sense since the power only goes out for a split second. Also the surge protector doesn’t flip off as well.

The kicker is the forth time, only two days after the third, when all the HDMI ports to my TV go bad. I was watching TV when my wife calls me to help her. Meanwhile there are a few lightning strikes and a slight flicker in the light. When I go back to the TV the power is turning on and off. I turn the TV off and then back on resulting in the TV power staying on. I test the cable box and Blu-Ray player. They both turn on but display "no signal". At this point I don’t know if the problem is in both boxes, the TV, or everything. I test the Blu-Ray player at my buddies’ house and discover it is working just fine. I also test the TV with my laptop with a "no signal" displayed. I am able to get picture through the coax. I have not tested the cable box at this point believing the problem to lie with the TV’s HDMI ports.

Currently I am awaiting the repair guy to come over this Saturday. I have called my insurance agent to start a claim. And I have placed a report with my apartment complex about the possibility of faulty wiring or grounding. My complex however refuses to believe it is an electrical issue and claims that the HDMI cables are creating a surge when the power drops. Initially I believed them to be a bunch of quacks but after reading the above referenced forum post I am starting to wonder.

Currently I do NOT have the Coax going thru a surge suppressor. However that doesn’t make complete sense because the cable line is split, one side going to the cable box and the other going to a high speed internet router. If the power spikes are occurring through the cable line then the router would certainly have blown. Then again if we are talking about grounding to the shortest path, I potentially could see the surge occurring through the power lines and grounding at the coax. Bypassing the router completely.

At this point the TV will get fixed but I don’t want the problem to keep occurring. Does anyone have a clue what might be the real issue?
post #2 of 11
If you have a Digital Multi-Meter, measure for any voltage at any of the cable lines in the house. Do not do it at the Static block on the side of the house, until you go to each line in the house to check for any voltage on the coax lines. Once you find if there is any voltage, then go to the line that is at the static block outside, that goes to the first splitter, and check at that line between the splitter and static block for the CATV company. If you measure voltage, contact the CATV company and an electrician both.

Usually if there is a sign of voltage on the coax, that means you have either grounding issues inside the house, or a loose Neutral. If everything checks out and the CATV states it is not on their end, but the electrician states it is on the Power Company side, then contact the Power Company and request a line check from your residence to their transformer.

If the CATV company unhooks the coax from the static block, and there is voltage on the line, you have a loose Neutral, you will have more than blown HDMI ports, it can cause a large electrical surge through the house, that can knock out anything connected to outlets. What happens, is that your coax now becomes the return path to ground, because there is no Neutral, or a corroded Neutral connection.
post #3 of 11
Quote:
If the CATV company unhooks the coax from the static block, and there is voltage on the line, you have a loose Neutral,

No not necessarily. It could be due to a malfunctioning CATV distribution amp, most of which are supplied power by the coax trunk feeding them.

Take gregs advice with a very large grain of salt.
post #4 of 11
I have seen several instances in the past, where equipment subject to surges from storms or power problems, had audio circuits that failed afterwards. The equipment power supplies and tuners directly in line with incoming surges were ok. But the audio circuits seemed to be the weak link that failed afterwards.
I am beginning to think that maybe HDMI circuits are the weak link for current equipment. Everything else is surviving the surge except HDMI.
If this is the case, hopefully manufacturers will make the needed changes so they can better survive these problems.
THe only foolproof way for equipment to survive these is to be disconnected from power and coax, or anything else coming from outside, during storms. Of course this is only true if the lightning bolt doesn't physically slice thru the equipment.
post #5 of 11
Quote:
Originally Posted by dbdoc View Post

I have seen several instances in the past, where equipment subject to surges from storms or power problems, had audio circuits that failed afterwards. The equipment power supplies and tuners directly in line with incoming surges were ok. But the audio circuits seemed to be the weak link that failed afterwards.
I am beginning to think that maybe HDMI circuits are the weak link for current equipment. Everything else is surviving the surge except HDMI.
If this is the case, hopefully manufacturers will make the needed changes so they can better survive these problems.
THe only foolproof way for equipment to survive these is to be disconnected from power and coax, or anything else coming from outside, during storms. Of course this is only true if the lightning bolt doesn't physically slice thru the equipment.
They could do the double layer protection. Replace the outlet that they are using for the equipment, with a Surge protection outlet like this http://www.legrand.us/categories/surgeprotectorspowerstrips/surge-protective-outlets.aspx then plug in the surge strip or UPS. Going into the panel and adding a Surge protection breaker, they would have to know the make of the panel, to find the right breaker, but some landlords may get skittish if a renter did that. If the person owns the apartment or condo, I see no problem going in and adding the in panel protection, or having an electrician install a out of the panel style surge protection.
post #6 of 11
I was looking at some of the other threads on HDMI failure. I have seen a couple of posts by 'service techs' using buzz words like 'fryed board' and 'blown HDMI ports'. I haven't seen any posts by an electronic tech who troubleshoots to component level saying what is failing in units with HDMI problems. I haven't seen any of these units myself. My best guess would be that any circuit failure outside of a unit's power supply or tuner, which are directly in line with incoming surges/instability on power lines or coax lines, would be coming from power surges coming into the unit's power supply. The unit's power supply is the common link to all the other circuitry. The power supply supplies the proper voltages to various circuits and keeps these voltages constant when voltage sources fluctuate. There is a limit to how much regulation these power supplies can provide. So any circuit component that is originally defective, but operating under normal conditions, or a poorly designed circuit or choice of components can cause a failure if there is a power problem. Equipment that runs 24/7 can be on the edge of failure and not fail until power is interupted.
I am skeptical about a cable box, for instance, that has a failed HDMI port, causing a surge thru the HDMI cable and taking out a tv's HDMI port. But stranger things have happened. That is what makes electronics so fun.
post #7 of 11
Quote:
Originally Posted by dbdoc View Post

I am beginning to think that maybe HDMI circuits are the weak link for current equipment.
They are. It is no secret, although not advertised.
Quote:
If this is the case, hopefully manufacturers will make the needed changes so they can better survive these problems
If they could have, they would have. Unfortunately effective, affordable surge protection for high speed devices is problematic. The answer is to keep the surges out of the connected equipment in the first place.
post #8 of 11
Quote:
Originally Posted by dbdoc View Post

I was looking at some of the other threads on HDMI failure. I have seen a couple of posts by 'service techs' using buzz words like 'fryed board' and 'blown HDMI ports'. I haven't seen any posts by an electronic tech who troubleshoots to component level saying what is failing in units with HDMI problems.
The reason you don't hear much about component level service is because the boards cannot generally be serviced at the component level. part spacing density is too tight to access the parts for replacement or often even measuring signals. Schematics are usually poor or non-existent, sometimes only a block diagram or less. Many individual parts have not been imported to the USA at all. Manufacturers make running changes in design as they switch vendors for components and assembly, so often they don't even bother to publish schematics for their own service centers.

I have seen the HDMI interface chips with their tops literally blown off and high current devices that drive things like Plasma panels have been known to catch fire.
Quote:
I haven't seen any of these units myself. My best guess would be that any circuit failure outside of a unit's power supply or tuner, which are directly in line with incoming surges/instability on power lines or coax lines, would be coming from power surges coming into the unit's power supply. The unit's power supply is the common link to all the other circuitry. The power supply supplies the proper voltages to various circuits and keeps these voltages constant when voltage sources fluctuate. There is a limit to how much regulation these power supplies can provide. So any circuit component that is originally defective, but operating under normal conditions, or a poorly designed circuit or choice of components can cause a failure if there is a power problem. Equipment that runs 24/7 can be on the edge of failure and not fail until power is interupted. I am skeptical about a cable box, for instance, that has a failed HDMI port, causing a surge thru the HDMI cable and taking out a tv's HDMI port. But stranger things have happened. That is what makes electronics so fun.
From schematics that I have seen that are somewhat complete the HDMI pins are directly connected to a processing chip with no buffer circuitry. (in the "old days" real world connections like buttons and jacks were isolated from delicate processors with some sort of buffer) The chips are very sensitive to static discharge. Some Owner's Manuals actually specify that both devices should be unplugged before connecting or disconnecting an HDMI cable despite the format being "hot swappable". If a chip shorts out it can feed it's power supply voltages onto the HDMI pins, damaging the other connected device, killing it. Also since the interface chip shares the Data Buss with all of the other processors in the TV, an HDMI failure can kill the entire set.

You could kill a TV that is actually unplugged from AC power if a static discharge passed from another device through the HDMI interface, shorting out the interface chip and locking up the Data lines so the TV could never turn on.
post #9 of 11
Good info, thanks. I am still able to repair some of the current pro AV stuff to component level. We are just beginning to use HDMI for video distribution where I work, so I imagine I will be getting a little more hands on for this stuff soon.
HDMI is relatively new. Manufacturers can and will make changes as they see fit. They have to balance cost and size versus reliability.
post #10 of 11
They need to start using HD-SDI and go back to using a single coax cable.
HDMI is ridiculous.
post #11 of 11
Quote:
Originally Posted by dbdoc View Post

Good info, thanks. I am still able to repair some of the current pro AV stuff to component level. We are just beginning to use HDMI for video distribution where I work, so I imagine I will be getting a little more hands on for this stuff soon.
HDMI is relatively new. Manufacturers can and will make changes as they see fit. They have to balance cost and size versus reliability.
A/V equipment still has multiple circuit boards inside, so even a major HDMI failure might require a single (simple) board replacement. Modern TVs often have only one circuit board. Sometimes even the power supply is part of the main board on smaller sets. And a main board replacement can cost as much as the TV cost new in extreme cases.

HDMI was not well though out. Hot swapping static sensitive devices and no cable retention on a multi pin connectors?? Born to fail.
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