Element ELEFW40C won't turn on.

[Spork Schivago]

Hi. I have an Element ELEFW40C that won't turn on. There's a solid red power light and if I hit the on button on the side of the television or use the remote control, it doesn't turn on.

I pulled the cover off and the logic board and power board are all one. I've uploaded some pictures, if you need clearer pictures of a certain part, please let me know.

I was going to try and jump start the TV but there's no PS_ON pin. Does anyone know how I can try and force this television on or does anyone have any suggestions on what might be wrong?

I'd like to add that the board bit me when I had the TV unplugged. I removed the case and was trying to remove a connector when I rested my hand on something that had juice. Not really sure what it was though. I'd have thought the 400V capacitor wouldn't hurt because TVs have bleeder resistors and everything. But it felt like a high voltage. It made me swear a little bit. I don't know if that's important or not to mention, but I felt I should say something in case it was.

Thanks!

[dskall]

Re: Element ELEFW40C won't turn on.

Ya power boards are like unloaded guns. Many unloaded guns have killed people. Never assume a gun or power board is harmless tell you check it. In this case you want to check your voltage across the big capacitor and discharge it. It can kill you. 3,000 posts and your still around though?

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

Ya power boards are like unloaded guns. Many unloaded guns have killed people. Never assume a gun or power board is harmless tell you check it. In this case you want to check your voltage across the big capacitor and discharge it. It can kill you. 3,000 posts and your still around though?

Slow learner I guess! I thought those bleeder resistors were supposed to prevent people from getting zapped by these things. Can a 400V capacitor really kill a person though? That sounds a bit hard to believe! This capacitor is a 400V 120uF cap. We can figure out how much energy, in joules, that capacitor has, using the following formula: 1/2 CV^2 where is the capacitance, in Farads, and V is the voltage. So, if we input our numbers we get:
1/2 * 0.00012 * 400^2
1/2 * 0.00012 * 160000
0.00006 * 160000
9.6 joules.

I believe a defibrillator will zap you with around 100 to 400 joules of electricity. So, I'm going to (and possibly falsely) assume that 9.6 joules just isn't nearly enough to kill me.

It's not the cap that I touched. It's one of those diodes next to the caps, one of the big ones. I just touched it again on accident, but this time it wasn't so bad! I really must be a slow learner!!!!!

147VDC on that cap!!!!! Each of those diodes have less. For example, the first one is around 87V, then the second might be half that, then the third might be half that, then the fourth (and last one) is around something low, like 2VDC if I remember.

[dskall]

Re: Element ELEFW40C won't turn on.

Yes If you read safety precautions in the manual they suggest having someone there while working on one to give you cpr incase you screw up. Also it is suggested you work with one hand in your pocket so if you contact high voltage it won't go through your heart and stop it.

[dskall]

Re: Element ELEFW40C won't turn on.

I am just learning this stuff and am not familiar yet with how to troubleshoot an integrated board and I found no service manual for it so short of trying to keep you alive someone else will have to jump in and help troubleshoot.

[budm]

Re: Element ELEFW40C won't turn on.

Its the current that kill you, at least plug what you are working on into GFCI outlet.
https://www.physics.ohio-state.edu/~...l_current.html
You are working in the primary side of the circuit so any thing you touch will have current flowing through your body to GND.

[martino]

Re: Element ELEFW40C won't turn on.

following,I got several of these kicking around doing the same thing.I'm suspecting brain dead (eeprom kaput) but never bothered yet to dive into them.

[Agent24]

Re: Element ELEFW40C won't turn on.

Slow learner I guess! I thought those bleeder resistors were supposed to prevent people from getting zapped by these things.

Yes, but they don't discharge it instantly. It could take up to 30 seconds, maybe more, for it to discharge to a low voltage (under, say 12v)

I believe a defibrillator will zap you with around 100 to 400 joules of electricity. So, I'm going to (and possibly falsely) assume that 9.6 joules just isn't nearly enough to kill me.

The problem is not that the small shock will stop your heart, but that it may make it start beating improperly, and enter a state in which it is actually unable to pump blood around your body. This "ventricular fibrillation" cannot really be dealt with by the body itself, and so the defibrillator is used to 'reset' the heart.

[waqqas.qayyum1]

Re: Element ELEFW40C won't turn on.

I want to make one master and three slaves. How can I set dip switch setting so that one can work as master and control the remaining three as slaves. Kindly please send me the instruction manual for dip switch settings for 1 master and 3 salves first. Also guide me what is the functionality of the dip switch. Is it something related to time or setting for master and slave. Please guide me as soon as possible so that I can place an order for my project.

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

Its the current that kill you, at least plug what you are working on into GFCI outlet.
https://www.physics.ohio-state.edu/~...l_current.html
You are working in the primary side of the circuit so any thing you touch will have current flowing through your body to GND.

This was totally unplugged. I thought all modern day TVs had resistors that would discharge a television shortly after unplugging it. I know the last CRT I worked on did. Is this not the case? The reason I ask is because if this cap should have been discharged, perhaps that'll give me a starting point.

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

Yes, but they don't discharge it instantly. It could take up to 30 seconds, maybe more, for it to discharge to a low voltage (under, say 12v)



The problem is not that the small shock will stop your heart, but that it may make it start beating improperly, and enter a state in which it is actually unable to pump blood around your body. This "ventricular fibrillation" cannot really be dealt with by the body itself, and so the defibrillator is used to 'reset' the heart.

So are you saying a 400V 120uF capacitor is enough to kill a person? I just find that very hard to believe!

This thing was unplugged for about 2 hours or so. I figure that should have been more than enough time. The jolt I got was around what'd you'd expect if you touched 120VAC.

Later today, I'm going to start by pulling some of those diodes on the PSU and making sure they're good. I'll go from there I guess.

[dick_barton]

Re: Element ELEFW40C won't turn on.

So are you saying a 400V 120uF capacitor is enough to kill a person? I just find that very hard to believe!

Some info on the web:-
The rule of thumb is 50 VAC or 120 VDC is considered the danger limit, take these as guidelines as the limits will change with humidity and other environmental factors. Whether or not these voltages are lethal really depends on the situation.

[CapLeaker]

Re: Element ELEFW40C won't turn on.

So are you saying a 400V 120uF capacitor is enough to kill a person? I just find that very hard to believe!

I don't want to flame someone or flaming myself, but reading this get's my neck hair straight up. One should always respect power. True, that some are more 'tolerant' to electric shock, but that has serious dependencies. For the general public just don't do it, specifically anyone new in the game / learners. Comments like that above don't help at all...

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

I don't want to flame someone or flaming myself, but reading this get's my neck hair straight up. One should always respect power. True, that some are more 'tolerant' to electric shock, but that has serious dependencies. For the general public just don't do it, specifically anyone new in the game / learners. Comments like that above don't help at all...

My post about how I thought this capacitor couldn't kill someone didn't mean to imply that I shouldn't have discharged it first. Safety first, right? From what I've read though, a 120uF 400V cap just isn't capable of killing anyone. One of us is wrong. Either me or him, either way, I feel someone should correct the wrong person. That's how we learn, you know what I'm saying? No sense in believing something that simply isn't true.

Budm was correct in stating it's not the voltage, but it's the current that kills you. I just don't think a 120uF 400V cap has enough current to kill a person. The device was completely turned off. If I'm really wrong on this, I'd love to know.

There's stun guns that have a lot more voltage and don't kill. I've been shocked by a spark plug more than a few times and they won't kill, they just lack the current. That's not to say a large enough capacitor couldn't kill a person, but I think minus a bit of a shock, this was (albeit a bit stupid), not really a life or death situation.

The reason I posted about the cap shocking me was because I honestly thought this shouldn't happen. The television was off for at least 2 hours before I ripped it apart. I feel like maybe this gives me an idea of what might be wrong with it, unless of course, not all modern day TVs discharge larger capacitors fairly quick like.

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

Some info on the web:-
The rule of thumb is 50 VAC or 120 VDC is considered the danger limit, take these as guidelines as the limits will change with humidity and other environmental factors. Whether or not these voltages are lethal really depends on the situation.

Getting a bit off topic here, but I don't think the voltages mean much. For example, my friend has a stun gun that's around 50,000V and we used to stun each other with it for fun. The voltage isn't what really matters, it's the current (measured in amperages), as Budm said. So, I think 10VAC or 10VDC _could_ be lethal, 50,000VAC or 50,000VDC _could_ be safe. It all depends on how much current is going through. This is why I posted that I found it very unlikely that this cap could kill me. There is a lot of misinformation out there and if he's learning, I felt we should maybe dig a little deeper into this topic. I know I couldn't tell you what size cap can kill me, so I still need to learn more. I believe a higher farad capacitor with a lower voltage is more dangerous than a lower farad capacitor with a higher voltage...

[dskall]

Re: Element ELEFW40C won't turn on.

Yes I am just learning. I haven't tested what will kill me voltage/current wise. I always check voltage. I have had several smps with 125v on them several hours after they had been unplugged. I am learning and was surprised there was such high voltage. Maybe because I am new I am just overly cautious.
Because I am just learning I would also like to know how to test pson on an integrated power/main board.

[Spork Schivago]

Re: Element ELEFW40C won't turn on.

It's always best to be overly cautious. You can never play it too safe, and from my experience, even when you are safe, sooner or later, you'll make a mistake. For example, I do discharge capacitors, but I always discharge the power supply caps after unhooking the connectors and removing the board. If I had discharged the cap before removing the board, I wouldn't have gotten shocked. So it's a lesson well learned. Current is what kills. It doesn't take much, but your body has resistance and can affect the current.

I think with capacitors, you should be a little more careful, especially when you're first learning about electronics. Electrolytics can explode if they're not handled properly. I think there's a greater chance of bodily harm from a cap exploding then there is from dying from it's charge. If the board is still powered, I guess that's a different situation all together.

The people on this forum are really nice and there's some extremely knowledgable members. There's an Electronic Theory and Troubleshooting section (right before this sub-forum I do believe) where you can ask questions and get wonderful help. I'm still learning. Personally, I don't think we should ever stop learning.

One think I'd like to add, even some of the smaller sized caps should be discharged I feel. If you get an ESR meter, a fully charged cap can sometimes damage them. If you're working with a soldering iron, a fully charged cap can damage that.

[budm]

Re: Element ELEFW40C won't turn on.

If the cap has charge Voltage of 400V and your body resistance of 40,000 Ohms (80,000 Ohms), you will then have 10mA (5mA) of current flowing through your body (you will feel that!), and after 1 time-constant, the Voltage on the cap will drop down to 63% of 400V.
If you touch the stun gun using EACH hand at each probe, then you have current flowing between two hands and your heart will be in the path of that current flow, the stun gun has probes close together to reduce that chance.
BTW, the CRT power supply may discharge, but the CRT itself can hold up charge for weeks.
Capacitor also has internal leakage resistance (very high vlaue) that cause the cap to self discharge.
I always measure the Voltage on the cap after the power cord is removed, just to be safe, if it needs to be discharged then I use resistor to do that.

[Agent24]

Re: Element ELEFW40C won't turn on.

With regards to a 120uF capacitor charged at 400v, I'm not actually sure. But I'm not going to grab one with one lead in each hand and see if it messes with my heart. Everyone is different though. It might not kill some people but it might kill others. Best practice is to check first before touching.

If you touch both leads with the same finger it will hurt but is unlikely to kill you as it's only going through your finger.

If the thing didn't discharge after 2 hours I am surprised, though, but indeed, it may be indicative of the fault, or just bad(?) design.

[budm]

Re: Element ELEFW40C won't turn on.

https://www.badcaps.net/forum/attach...1&d=1486337777
Picture is not clear enough to read those prints on the bottom side of the board, you also need to remove that black insulator sheet in the primary side so we see the prints under that too.