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Help needed if possible for DeWalt dcv582 PCB

Tonys1

New Member
Hi I am looking for some help if it’s not too much trouble ...
I have a pcb for a DeWalt hoover and it’s not working, i have found a blown fuse soldered to board and replaced it , but it’s blown again, so I looked some more and found what I believe to be an inductor but it has 4 legs and something in the middle dividing the two coils?
My questions are :
how can I tell what replacement to get ?
How does this inductor work as it appears to have 2 coils wound on a plastic hollow cylinder, with something dividing the 2 coils inside the hollow cylinder.
The photo below shows a good one and next to it you can see the burnt bit where I’ve desoldered the blown one ...
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
It's probably a mains filter, simply a dual wound choke - and not at all the sort of thing would go faulty. I would seriously doubt you could source a replacement?, as they don't go wrong, and even if DeWalt supply spares, it would only be a complete PSU.

Can you post a picture of the complete board, one a bit more in focus?.
 

Tonys1

New Member
Hi Nigel
Thanks for your reply
This choke is definitely bad it’s black and burnt,
The hoover went bad after the power supply (due to a faulty extension lead ) kept going on / off /on / off quite rapidly.
Could this be an exception to the rule?
The website won’t let me upload a decent picture sorry, I’ll keep trying.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi Nigel
Thanks for your reply
This choke is definitely bad it’s black and burnt,
The hoover went bad after the power supply (due to a faulty extension lead ) kept going on / off /on / off quite rapidly.
Could this be an exception to the rule?
To the left of the choke position is a load of sensitive electronics, a switch-mode power supply, it's far more likely that something in there has died, and haveing gone short circuit 'may' have destroyed the choke.

Without a schematic I'm just guessing, but assuming it it is just a mains filter? (as seems likely), then it has no functional operation in the working of the unit - it's there merely to reduce the interference from the power supply going back down the mains. Without it in place nothing works though, as the mains goes through it - there should be live in and live out, and neutral in and neutral out, you could temporarily (and carefully) fit two pieces of wire across to see if it works then. However, I suspect there will just be a big bang, as more serious parts are blown.

I'm assuming that's a piece of great thick wire across the fuse at the top in the picture :nailbiting:

That could explain why the choke has been destroyed as well - you MUST replace the fuse with the correct one, if you're going to try shorting the choke out, as it's extremely likely to blow instantly.
 

Tonys1

New Member
Thanks nigel
You have a good eye it’s not a wire but a long piece of solder
The fuse I replaced was the correct one it is 3.15A
The solder was so I didn’t go through loads of fuses , I’ve removed the choke, I’ll try to get another one and in the mean time I’ll start looking at the switchmode power supply parts to the left, hopefully I can find something, they’ve covered it in quite a lot of silicone
Thanks for your help it’s given me a target zone as this blew without the switch on which seems to coincide with your thoughts.
It’s just a project really if I can’t fix it no bother, I’m just interested in starting to repair electronics i want to see if I can fix a couple a hundred pound machine for the sake of a £4 part I’ll be happy
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thanks nigel
You have a good eye it’s not a wire but a long piece of solder
Solder IS a piece of wire :D

The fuse I replaced was the correct one it is 3.15A
The solder was so I didn’t go through loads of fuses , I’ve removed the choke, I’ll try to get another one and in the mean time I’ll start looking at the switchmode power supply parts to the left, hopefully I can find something, they’ve covered it in quite a lot of silicone
Thanks for your help it’s given me a target zone as this blew without the switch on which seems to coincide with your thoughts.
It’s just a project really if I can’t fix it no bother, I’m just interested in starting to repair electronics i want to see if I can fix a couple a hundred pound machine for the sake of a £4 part I’ll be happy
If it's any help, it's called a 'common mode choke', RS Components for example have hundreds of different ones.
 

unclejed613

Well-Known Member
Most Helpful Member
Solder IS a piece of wire :D
yeah, and bypassing a fuse with a piece of wire IS a BIG mistake, because what happens is that when you plug it back in, instead of having one shorted component to find, you are now burning up everything between the power line and the shorted component. especially your common mode choke, but maybe the primary of the switching transformer (and that's a part you CANNOT get a replacement for) after replacing the common mode choke, replace the fuse with the correct one, and wire an incandescent lamp (a 50 or 60 watt one) in SERIES with the incoming power line. because there is a short, the bulb will light up brightly, but there will be enough current through the power supply to do some voltage measurements (they will all be pretty low, but across the shorted component, that will be at or near 0 volts across it) and find the shorted component.
 
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