This started out as a mechanical solder joint failure due to a large heavy inductor that is not well mounted. Cracked solder joint then heated and burned. See it a lot on heavy components.
That is (was) very common type of failure in for example washingmachine programconroller boards.That happens because 1. Those components do heat a bit and that causes heat expansion and some stress to solderjoints2. Those componens (coils with ferrite inside) are "heavy", so any drops, kicks, hits and so on will cause stress to solderjointsOf course fuses wont blow, because there is (was) only poor connection, not a short circuit.That metal component near damage area looks like "microtemp" type heat fuse. Those are usually not automatically restoring type fuses that will cut off at marked Tf temperature (there should be temp markings in it, example Tf 240C). It could stop current before fire.Biggest danger there is that arcing happens first between coil leg and board trace, but board heats, burns and burnt hot board leaks current (seen that). If there is something near it can leak to, that can cause very hot secondary arcing (mean between "hot live" wire and ground wire) (that can cause fuse to blow eventually, but it may first cause heat energy enough for plastic to lit.That kind of component legs should be bent to the circuitboard atleast 3-10 mm and then be soldered. That´s only good fix for thatkind of problem. Soldering coming bad is so common failuremode..Happens because of poor manufacturing. Good manufacturing costs, so they wont do it if they just can get away with it..
Good video Kerry! I would be interested to see a follow-up to this video with the newer(post recalled) version of this product made after 2003 when, presumably, corrections were made to prevent the potential fire and smoke danger of the recalled units. I still have 3 of these in my home that were manufactured after the recall. I did have one of the recalled year units and APC replaced it for me at no charge. I would really like to know what improvements APC made to the circuit and if those changes were adequate. Thanks!
The silver/darkened fuse near the MOVs looks to be a thermal fuse, which is only one time use. It can pass 15A but I'm not actually sure what happens if its much higher. Then of course the resettable breaker that you've shown, attached to the wire, is likely setup for 15A.
perhaps it was a poor solder joint? that would explain why the fuse didn't blow. those heavy coils don't appear to be bonded to the board and they look like heavy gauge wire. looks like a perfect scenario for a solder joint failure. if the solder joint starts increasing in resistance then it wouldn't take very long for a lot of heat to build up there and of course, that area is not designed to dissipate much heat at all. thats my 2 cents.
Vibration could have contributed to the increased resistance at that joint. Those inductors are arranged such that, during normal operation, they will pull toward each other at the current crests and relax at the zero-crossings. So whatever holds those inductors in place, apparently just their lead wires, will see a little ping of force 120 times a second. It's a small force, not enough to hear or even really measure in this particular equipment, but all metals have a fatigue limit (measured in force times cycles) beyond which they will start to crack apart. A heavy load for years on end, combined with a few hard jolts, could eventually turn that inductor lead into a pretty good heater (which eventually destroyed the things around it).
Old video, but anyone know what that black-on-silver barrel part labelled F4 is on the board? I assume it's some sort of fuse, but i'm at a loss to figure out what the part number is.
The main fuse did blow. Suppose to be able to see thru the glass tube. Very high voltage! Surge vaporized the metal inside the fuse to the glass creating a pathway for electrons to keep flowing thru.
New home / office APC stuff is just cheap garbage, took a APC UPS apart and the protection diodes / movs fro the telco and newtwork protection are not installed, just the empty places in the cheap circuit board.
The ones I've looked at had a daughterboard with proper movs installed, but the grounding point was not connected! Not to mention the transformer is always powered and probably cooks the battery in no time. Also the one in this video looks like it has a proper switch, I have another APC surge protection strip where the crappy round rocker switch failed in less than a year.
Strange circuit design. An electronic circuit just for controlling the leds, irrelevant to any protection purpose. And for the energy needed to light up these leds, the fuse, instead of being located right after the line input coil, before the MOV in order to play its protective role by being melted after a surge, is located after the MOV, where it serves no purpose at all as regards overvoltage protection. It simply protects the load in case of short circuit. As for the leds' circuit itself, I wonder who could see the instantaneous led light changeover as there is not any "memory" circuit there and finally what would be the benefit of seeing it, if it were noticed. As regards the input coils, given that their wire diameter is big, their terminals should be left longer and bent in a rectangular anle touching the pcb at the solder side of it, offering them a much higher immunity against any vibration problems and better solder joints with much less resistance at these points. Another question is if their wire is copper or aluminum...
This started out as a mechanical solder joint failure due to a large heavy inductor that is not well mounted. Cracked solder joint then heated and burned. See it a lot on heavy components.
Several models of APC surge protectors were recalled, so it's good to check the list online. I received free replacements for all of mine.
Alright, The surge suppressor protected the fuse. It worked.
That is (was) very common type of failure in for example washingmachine programconroller boards.That happens because 1. Those components do heat a bit and that causes heat expansion and some stress to solderjoints2. Those componens (coils with ferrite inside) are "heavy", so any drops, kicks, hits and so on will cause stress to solderjointsOf course fuses wont blow, because there is (was) only poor connection, not a short circuit.That metal component near damage area looks like "microtemp" type heat fuse. Those are usually not automatically restoring type fuses that will cut off at marked Tf temperature (there should be temp markings in it, example Tf 240C). It could stop current before fire.Biggest danger there is that arcing happens first between coil leg and board trace, but board heats, burns and burnt hot board leaks current (seen that). If there is something near it can leak to, that can cause very hot secondary arcing (mean between "hot live" wire and ground wire) (that can cause fuse to blow eventually, but it may first cause heat energy enough for plastic to lit.That kind of component legs should be bent to the circuitboard atleast 3-10 mm and then be soldered. That´s only good fix for thatkind of problem. Soldering coming bad is so common failuremode..Happens because of poor manufacturing. Good manufacturing costs, so they wont do it if they just can get away with it..
Good video Kerry! I would be interested to see a follow-up to this video with the newer(post recalled) version of this product made after 2003 when, presumably, corrections were made to prevent the potential fire and smoke danger of the recalled units. I still have 3 of these in my home that were manufactured after the recall. I did have one of the recalled year units and APC replaced it for me at no charge. I would really like to know what improvements APC made to the circuit and if those changes were adequate. Thanks!
The silver/darkened fuse near the MOVs looks to be a thermal fuse, which is only one time use. It can pass 15A but I'm not actually sure what happens if its much higher. Then of course the resettable breaker that you've shown, attached to the wire, is likely setup for 15A.
The darkened fuse is still intact. The main fuse is rated for 25A.
perhaps it was a poor solder joint? that would explain why the fuse didn't blow. those heavy coils don't appear to be bonded to the board and they look like heavy gauge wire. looks like a perfect scenario for a solder joint failure. if the solder joint starts increasing in resistance then it wouldn't take very long for a lot of heat to build up there and of course, that area is not designed to dissipate much heat at all. thats my 2 cents.
Vibration could have contributed to the increased resistance at that joint. Those inductors are arranged such that, during normal operation, they will pull toward each other at the current crests and relax at the zero-crossings. So whatever holds those inductors in place, apparently just their lead wires, will see a little ping of force 120 times a second. It's a small force, not enough to hear or even really measure in this particular equipment, but all metals have a fatigue limit (measured in force times cycles) beyond which they will start to crack apart. A heavy load for years on end, combined with a few hard jolts, could eventually turn that inductor lead into a pretty good heater (which eventually destroyed the things around it).
I fully agree. This seems to be the most likely failure scenario. Poor solder joint in combination with heavy load for long time...
Old video, but anyone know what that black-on-silver barrel part labelled F4 is on the board? I assume it's some sort of fuse, but i'm at a loss to figure out what the part number is.
I just had one of these recalled surge protectors fail (PRF8TT). Interestingly, the power switch is what failed.
The fuse protection for slow over current but not TVS
Good job.
Excellent, thanks!
Maybe you could test the fuse to see what it takes to blow it?
The fuse is rated for 25A.
The main fuse did blow. Suppose to be able to see thru the glass tube. Very high voltage! Surge vaporized the metal inside the fuse to the glass creating a pathway for electrons to keep flowing thru.
Or... it's a ceramic HRC fuse.
@@ickipoo eat a fish catch a voter! Then throw it back and catch a voter! With debt!
@@brianwaiting7899 It's a ceramic HRC fuse.
Those Movs should have thermal fuses strapped to them...
I had a fire in my apartment from one of these should have sued the company it happened back in 2015.
As you can see as my hand is in the way.....
Bcz Now APC not made in EU or USA. Just in China or Philippines or Bangalore ..
Where cheap labor and more profit ..
hey Big help 2021
You forgot the X2 capacitor in the circuit.
Oops, yeah it goes right before the chokes :)
New home / office APC stuff is just cheap garbage, took a APC UPS apart and the protection diodes / movs fro the telco and newtwork protection are not installed, just the empty places in the cheap circuit board.
Bcz APC not now made in EU or USA. Just in China or Philippines or Bangalore ..
Where cheap labor and more profit ..
The ones I've looked at had a daughterboard with proper movs installed, but the grounding point was not connected!
Not to mention the transformer is always powered and probably cooks the battery in no time.
Also the one in this video looks like it has a proper switch, I have another APC surge protection strip where the crappy round rocker switch failed in less than a year.
Coincidence or not that one I took apart the battery was dead.
Strange circuit design. An electronic circuit just for controlling the leds, irrelevant to any protection purpose. And for the energy needed to light up these leds, the fuse, instead of being located right after the line input coil, before the MOV in order to play its protective role by being melted after a surge, is located after the MOV, where it serves no purpose at all as regards overvoltage protection. It simply protects the load in case of short circuit. As for the leds' circuit itself, I wonder who could see the instantaneous led light changeover as there is not any "memory" circuit there and finally what would be the benefit of seeing it, if it were noticed. As regards the input coils, given that their wire diameter is big, their terminals should be left longer and bent in a rectangular anle touching the pcb at the solder side of it, offering them a much higher immunity against any vibration problems and better solder joints with much less resistance at these points. Another question is if their wire is copper or aluminum...
E=Mc2