Replace power supply, without output and polarity information

Thread Starter

LalaGhost

Joined Sep 11, 2019
5
Hey, I have not a lot knowledge about that stuff but I am planning to learn a bit of soldering and trying to fix a broken sub-woofer.
So the sub-woofer says following on the back:
AC 230V~50Hz/150mA

One of my pins on the end of the power supply cable broke and would like to replace the cable.
But most of the cables I want to buy have information about polarity and output but my device says nothing about it.
How do I decide what cable to buy?
 

LesJones

Joined Jan 8, 2017
2,956
When you say "power supply cable" it sounds like you are talking about a power supply. Can you post pictures of the cable and close ups of the connectors on each end of it. (Also showing the broken pin.) Can you also post a picture of the power connector on the sub-woofer.

Les.
 

MaxHeadRoom

Joined Jul 18, 2013
22,374
Do you have any old/scrap appliances, if so you could maybe cannibalize one from them.
Old PC cable etc.
Before I scrap any appliance I usually clip the power cord off.
Another option is obtain/purchase a new plug end.
If polarity sensitive, check old one with a meter.
Max.
 

LesJones

Joined Jan 8, 2017
2,956
Hi Max,
That plug looks like the type of plug that is used in most European countries. (Not the UK.) It has two pins with both pins the same diameter so it can be inserted either way so polarity does not matter.

Les.
 

MisterBill2

Joined Jan 23, 2018
7,998
Indeed, that broken plug looks like it is the mains connection for the device. And given that the mains source connection only has 2 pins, and that those pins are identical, except that one is broken, you should be able to purchase just a replacement connector and not need to deal with replacing the cable. And since the subwoofer has an internal transformer it is definitely an AC connection, not DC. So while there is a preference for which wire connects to which pin, it will operate just as well with either connection.
So purchase a replacement connector, cut off the molded on connector with the broken pin, and install the replacement connector. Since Blue and Brown are widely used, you should be able to find out from somebody in this website which is line and which is neutral. Please avoid trying to replace that cord, since that is a good way to damage the amplifier if you make an error.
 

Thread Starter

LalaGhost

Joined Sep 11, 2019
5
Yes, I am from Europe
So all I need to do is to buy a new connector and replace the old one?
No soldering or something like this?
That I will soldering another way, thanks for your help! :)
 

Thread Starter

LalaGhost

Joined Sep 11, 2019
5
One more thing, the old connector is some molded rubber and I dont know how to take it off without damaging the whole thing?
Or do I just cut the cord right at the end?
 

MaxHeadRoom

Joined Jul 18, 2013
22,374
Normally a replacement cord plug is available at most electrical hardware stores etc.
Cut the old one right off and when you fit the new one, usually screw connection and some means of strain relief.
Max.
 

MisterBill2

Joined Jan 23, 2018
7,998
I say let the man learn!:p
Max.
Max, I have seen photos of some folks efforts at soldering and they are UGLY!!! There are lots of places to solder that can provide a good learning experience, but without the risk of destroying a useful and probably somewhat expensive device like a power supply. And I try to direct folks towards less painful learning experiences. I do that out of kindness.
 

MisterBill2

Joined Jan 23, 2018
7,998
I’m in the you gotta break few eggs to bake a cake camp. I know one thing leads to another but that’s how you learn.
Far to often I have been tasked with repairing the damage and destruction caused by those who did not know what they were doing let that stop them. The destruction caused by the allegedly well meaning folks can be astounding. And those who dispose of items that they do not recognize, which do not belong to them, often are responsible for large expenses to replace those missing items.
So for those with unlimited funds may choose to learn by destruction, that is their problem.
My choice is learning by asking and observing.
 

Wolframore

Joined Jan 21, 2019
2,235
In Denmark, a typical plug, with screws for the cord, looks like this:
That’s the best idea yet. But if you’re main concern is pricing similar product here in the US (we use NEMA plugs for 240V) are expensive compared with just cutting a plug from a bad device and either soldering or crimping blade pins or even splicing. All takes some skills but it’s not that hard.

These plugs if not done correctly could be dangerous also. If any bare wire is showing and I’m sure there are not water proof.
 
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