Power Inlet problem - help me i'm melting!

[grippie]

So i've had my sega genesis bartop for awhile and put plenty of hours on it. I went out to the garage to try and beat ghost's n goblin's last night, and after about 20 minutes I smelled something burning. I checked the PC and power supply to make sure I wasn't nuking the system but didn't see anything wrong. I shut down and did a closer look and saw that the power inlet had melted the black patch cable in the middle. see pic 1. After unplugging everything and taking the piece out, It actually melted the plastic around the male prong and it came loose!!!. see pic 2 I'm assuming this thing is toast now and i'll have to replace it, but my question is why did this happen? I'm pretty sure I used heavy enough wire. It may have been from the excess power supply wire that I cut off, so why did it get so hot and melt???
 

[vwalbridge]

Did the fuse inside blow?

I'm willing to bet it was the gauge of the jumper wire you used. I always use the wire from a computer power cord, extension cord or solid copper 12 or 14 AWG.

Also, I prefer insulated spade terminals vs soldering for this application. You shouldn't have those kinds of terminals exposed.  Here is a picture of the one I just did. (I wired mine differently than yours. I wanted to turn on my marquee light separate from my arcade.)

[BadMouth]

There had to be some type of resistance generating heat.
Wire too small, corroded, poor connection, pinched, etc.
What size wire is that and what size fuse was in it?
EDIT: Could have also been the switch since you say it melted around the terminal.  Is the switch melted?

I had a similar thing happen on the end of the cable where it connects.
I'd used a random old PC cable that was laying around.  Either the contacts were corroded or had loosened up so there wasn't a solid connection.
I switched to a brand new 14 gauge cable and haven't had any issues since.  (of course replaced the inlet also)

[grippie]

Yea i'm unsure as to what gage the wire is. I am pretty sure it's the same wire from the power supply which i would assume is thick enough. I'll probably have to buy a new inlet and make sure that I get better wire. I'll try some 14ga to make sure it's enough. I don't think the fuse blew as the power was still connected until i shut down. I will take it out and look at it tonight.


I originally had quick connects on there, but because of space constraints, I had to solder them directly. They would slam into the subwoofer...

[PL1]

Make sure you have a good mechanical as well as a good electrical connection when you solder in the replacement inlet and wires.

If only a few strands of the power cable are making contact with the terminal, the connection will still ohm out OK, but those strands will have to carry the entire electrical load over that narrow connection.

This can lead to a vicious cycle where the current flowing through that narrow connection generates heat which causes the wire to corrode which increases the connection resistance which generates more heat . . .   


Scott

[DaOld Man]

This type problem is usually caused by a loose connection.
If you use too much heat when soldering, the pin may twist or get out of alignment, then the plastic hardens and you never know.
Until the plug with the cord doesnt fit the misaligned pin as designed, and after a while heat is generated, which misaligns the pin even more, then before you know it you have a melt down.
Bad solder joints, too much heat, and even factory defective or damaged plugs can do this.
Whenever this happens, you need to replace both the plug on your box and the cord or at least the plug on the cord.
This can be very dangerous, as it can cause fires if there is anything flammable close to it. Dust, lint, most cloths, and flammable liquids can ignite from the heat generated by the loose connection.

[lilshawn]

your problem is likely 2 fold...

the wire, if cut from a power supply cable, could still be undersized for the load it's carrying. lots of those cables are "rated" for 10 or 12 amps, but the wire it contains is probably only rated for 5 at most. i've stripped back many a computer cable and even though they are stamped 18ga the wires it contains have been more like 24ga which can only handle about 2 or 3 amps.

secondly, I see you've soldered the wires. these copper wires don't take too kindly to being heated to high temperatures and will oxidise quickly when heated. the short length you have there exasperates this condition by having 2 points of entry for oxygen to get in after it's been soldered and put into service. the oxygen gets in there and eats at the copper...eventually the copper oxides through and the increased resistance caused by it causes the conductor to heat up, make the problem even worse.

you can reduce this issue by using a larger gauge loop of wire or even a piece of solid conductor like romex or best of all, using a IEC block that has the switch already hardwired to the power like so...

http://www.cpaltd.net/rip.php

basically has the IEC input and a tabbed output for a faston style push on connector. no farting around with the switch wiring or anything. it's all internally connected with bus bars.

i think you just have an unfortunate series of events occur that snowballed into your problem. no biggie. best you caught it now than leaving the machine on and going for lunch.

[grippie]

i think you just have an unfortunate series of events occur that snowballed into your problem. no biggie. best you caught it now than leaving the machine on and going for lunch.

Thanks for all of the advice guys. i think this sums it all up pretty nicely. I'll look into some more robust options for the connection. Just ordered an other power inlet that will be here Wednesday.


Is it safe to hotglue this area to seal it from the elements? Usually hot glue is great for internal components that need to be sealed and stay in place but they usually don't carry this much juice. Or is the hot glue just another flammable substance in this instance and a resin would be more suitable? I have been keeping this in the garage so i'm sure the elements are a little more rough than the living room and it would be helpful to protect this connection.

[RandyT]

To my eyes, this is definitely a case of a poorly fitting AC female socket.  If you have a poor connection, coupled with a sizable amount of current, you get arcing.  If the amount of current consumed by the arcing isn't higher than what the fuse/breaker is rated for, they don't pop.  This is a particularly dangerous scenario, as there is little one can do in the way of protecting against it, other than ensuring good connections between the parts.  The same thing happened when they used solid aluminum wiring in early model mobile homes.  The constant heating and cooling of the wires (through use and from external temperature changes through the thin, poorly insulated walls) caused the wiring to crack.  The result was arcing and many fires.

This can also happen with old, worn out household AC receptacles.  About 25 years ago, I watched in horror as the receptacle my commercial BUNN coffee maker was plugged into, started spewing smoke like a jet engine. 

Same issue.

[grippie]

Thanks Randy,


Looking at the reviews on amazon, it looks like others have had melting problems. I'm hoping that better installation will help, but that worries me. I don't leave my machine on unattended, but dang...


http://www.amazon.com/URBEST%C2%AEInlet-Module-Switch-Socket-IEC320/dp/B00ME5YAPK/ref=cm_cr_pr_product_top?ie=UTF8

[BadMouth]

I keep mine unplugged when not in use.  More out of concern for lightning or power surges than anything else.

[pbj]

Those things have always looked like complete junk to me, so my Turtles cabinet uses an intake like off a PC power supply coupled with a DPST heavy duty toggle switch.  I figure that's about as safe as you're going to get given that it's also behind a power strip I keep flipped off when not in use. 

The idea that soldered copper wires are at fault is a new one to me and sounds ridiculous.

[2600]

Thanks Randy,


Looking at the reviews on amazon, it looks like others have had melting problems. I'm hoping that better installation will help, but that worries me. I don't leave my machine on unattended, but dang...


http://www.amazon.com/URBEST%C2%AEInlet-Module-Switch-Socket-IEC320/dp/B00ME5YAPK/ref=cm_cr_pr_product_top?ie=UTF8

If multiple people are reporting issues, then a better installation isn't going to solve your problem.  The part is crap.  I get people like to save a few bucks, but is this where you want to save it.  I wouldn't be surprised if the CE and other stampings are false.

[grippie]

I think the build quality of this unit is pretty solid and a lot of people on here have used this exact one. I just realized something and I think it's all my fault. I remembered that when I turned on my machine last time that I just pushed the on button. Last time I shut down I must have forgotten to flip the kill switch in the back meaning that power was flowing through the inlet to the power supply for at least a month. It probably had melted long before I turned it on and when I starting pulling more juice with the monitor and computer running, it just finished the job...


My new one will be here today. I bought some 12 GA wire made for power and will make sure I flip off the switch from now on. (And maybe even just unplug it completely to be sure)

[BadMouth]

Eh, power is only flowing if something is drawing it. 
Sitting there with the pc turned off shouldn't affect it and even if everything was left running for a month....the switch should be able to handle it. 
My bet is that this company is using cheap switches that are rated for less current than the fuse.

I'm pretty sure we have the same exact inlet and I'm glad I keep mine unplugged.   
On the next one, I'll forego the switch.

[pbj]

Do you guys really not keep your games plugged into power strips?  Kill them at the strip and forget about it.

[yotsuya]

Do you guys really not keep your games plugged into power strips?  Kill them at the strip and forget about it.

Amen. Mine go through two of these...

[grippie]

I said power supply but meant power strip.  Power flows until it hits a break so yes power is still flowing through the cable to the power strip.  My monitor and amp were still drawing power but the pc was off. 

[grippie]

Wired up the new one with my fancy new thick wire and I have no power. the light doesn't come on in the switch or anything. I double checked and nothing is touching or crossed and the wires are installed exactly like the old one. Not sure what to do but desolder and try different wires.

[yotsuya]

Wired up the new one with my fancy new thick wire and I have no power. the light doesn't come on in the switch or anything. I double checked and nothing is touching or crossed and the wires are installed exactly like the old one. Not sure what to do but desolder and try different wires.

Fuse?

[vwalbridge]

Wired up the new one with my fancy new thick wire and I have no power. the light doesn't come on in the switch or anything. I double checked and nothing is touching or crossed and the wires are installed exactly like the old one. Not sure what to do but desolder and try different wires.

Fuse?

Yep, check the fuse. And check to see if the inlet even HAS a fuse. Often these inlets come with out one. I know, that would be stupid but all the inlets I've purchased from Amazon don't come with fuses.

[yotsuya]

Wired up the new one with my fancy new thick wire and I have no power. the light doesn't come on in the switch or anything. I double checked and nothing is touching or crossed and the wires are installed exactly like the old one. Not sure what to do but desolder and try different wires.

Fuse?

Yep, check the fuse. And check to see if the inlet even HAS a fuse. Often these inlets come with out one. I know, that would be stupid but all the inlets I've purchased from Amazon don't come with fuses.

Exactly. Same here.

[grippie]

Yea it came with a fuse and I even tried my old fuse from the last one which worked....

[vwalbridge]

Yea it came with a fuse and I even tried my old fuse from the last one which worked....

Post some pics and let's have a look at it.

[grippie]

Don't judge in not an electrician lol. The sold cable was hard to work with but its connected pretty well. 


Sent from my iPhone using Tapatalk

[yotsuya]

That does not look right at all.

[grippie]

That does not look right at all.

care to elaborate a bit there yots? It's the same diagram as before.

[BadMouth]

Skip the switch.  The hell with it.
Pop it out and replace it with an Ethernet port.

[yotsuya]

That does not look right at all.

care to elaborate a bit there yots? It's the same diagram as before.

Ok, I zoomed in on you photo. I see the solid wires are very tight connections. Can you use a multimeter to make sure there is continuity between the entry pins and what is coming out?

[PL1]

Have you checked for continuity with your multimeter? (with it not plugged into wall socket so you don't fry your meter)

How many ohms are you reading from the wall plug to the power strip sockets?


Scott

[harveybirdman]

check the wiki, I thought those jumpers go on the other side of the switch.

[grippie]

I did pull out the multimeter and checked between each set of pins to make sure that there was a clean connection. I pulled out the fuse and tried pushing it in without the little plastic fuse holder and was able to get the switch to light up intermittently. I still didn't get power to the power strip, but it's closer.


The wires i used to extend the power supply are not good enough. I'm going to wire that up again with some better wire and check the connections with the multimeter then. I stopped at home during lunch to get the picture so i'll try this tonight and see what happens...

[grippie]

check the wiki, I thought those jumpers go on the other side of the switch.

I think you can do it either way. It just depends on if you want the light inside of the switch to illuminate all the time, or only when the circuit is broken (which mine is)

[PL1]

check the wiki, I thought those jumpers go on the other side of the switch.

The switch can be turned 180 degrees when installed.

The wider contacts usually have the lamp between them.

The diagram is right for the light being on only when power switch is closed.

I did pull out the multimeter and checked between each set of pins to make sure that there was a clean connection. I pulled out the fuse and tried pushing it in without the little plastic fuse holder and was able to get the switch to light up intermittently. I still didn't get power to the power strip, but it's closer.


The wires i used to extend the power supply are not good enough. I'm going to wire that up again with some better wire and check the connections with the multimeter then. I stopped at home during lunch to get the picture so i'll try this tonight and see what happens...

Sounds like crappy connections.   

Until you have CLEAN, SOLID connections that are two ohms or less from wall-plug to power strip, that is a possible fire risk.

DO NOT PLUG IT IN AGAIN UNTIL THOSE CONNECTIONS ARE FIXED.


Scott

[RandyT]

Something else to keep in mind when wiring these things is that really heavy gauge wire isn't going to necessarily make these better.  Likely, just harder to wire.  The assembly is limited by the terminals, and perhaps more importantly, the switch contact current rating.  Big wire in and big wire out won't change what the switch assembly can handle.  Given that these seem to be low-cost, Chinese items, the stated ratings might be optimistic, so I wouldn't push them too hard.

As a rule, the wiring of the switch assembly need only maintain the same wire gauge as the wires going in and out.  Jacketed, stranded wire is what I would stick with.  Covering the exposed connections would be a good idea as well, to prevent mishaps.

[grippie]

Thanks for the info PL1 and Randy. Yea I didn't realize how big the 12ga wire was until i tried to wire it up. and the coating kept getting ripped when trying to bend it. I will de-solder and clean it and make sure that i'm getting solid connections. I think i'll just sacrifice and old power plug and use those wires to complete the connections. Those large wires are a bit over kill!!!

[yotsuya]

Thanks for the info PL1 and Randy. Yea I didn't realize how big the 12ga wire was until i tried to wire it up. and the coating kept getting ripped when trying to bend it. I will de-solder and clean it and make sure that i'm getting solid connections. I think i'll just sacrifice and old power plug and use those wires to complete the connections. Those large wires are a bit over kill!!!

Are you able to use Quick Disconnects instead of soldering?

[PL1]

Are you able to use Quick Disconnects instead of soldering?

I originally had quick connects on there, but because of space constraints, I had to solder them directly. They would slam into the subwoofer...

Maybe if he used flag-style QDs.

   


Scott

[grippie]

Good news gents, it's alive


I desoldered all of the wires and cleaned up the connectors. I switched to using 16ga stranded wire so that it would be easier to work with. I also replaced the wires that were extended from the power supply as they were too small as well. Now i have a solid and clean connection that should be safe. I unplugged it after verifying that it works just in case. I'll wait till I get a few hours on it to make sure i'ts holding up.

Are you able to use Quick Disconnects instead of soldering?

There is only about a mm of space between the back of this inlet and the subwoofer.

Maybe if he used flag-style QDs.

Yes. Yes indeed. If only i'd known about those when I was fixing this up. I probably should have went to a true hardware or electronics store instead of just home depot to find my components.