Replacing a power cord?

[rspst14]

Hey guys, I have an MXR analog delay that I picked up dirt cheap because the plug on the power cord was cut off, and the owner didn't know how to fix it.  I bought a replacement cord, and I have a question about installing it.  I've identified the grounded middle prong wire, but without the plug end on the original cord, I don't know how the two wires soldered to the circuit board correspond to the other two prongs on the plug.  Does it matter which of the other two wires gets soldered to a certain spot on the board?  If I were to reverse them, and have the left prong wire soldered to where the old right prong wire was, will I run into problems?  Any help would be appreciated.  Thanks.

Ryan

[Hal]

im kind confused - not sure if i undersend you question...
BUT.  it should be negative ground.  Identifying the ground point shouldn't be too hard - sleve of the jacks should be grounded.  So use a meter on continuity, and connect the negative terminal of the adapter to the piont on the adapter that should be ground.  The positive terminal should NOT be continuous to ground.


Hope that answered your question.  If not...ask again.

[rspst14]

I tried to think of the best way to phrase this, I'm not sure I explained it very well.  The MXR analog delay has an AC power cord with three prongs.  On the original cord, the plug itself had been cut off, so I can't do a continuity test to determine which prong corresponds with which wire.  On the original cord, there are three wires: a green wire, a brown wire, and a blue wire.  It's obvious that the green wire corresponds to the middle prong of a three prong plug, as it is grounded.  The brown and blue wires are soldered to the board, and they are the wires for the left and right prongs.  The problem is, I don't know which wire corresponds to which prong, so that I can solder in the replacement cord in the same way.  What I'm not sure about is whether or not it's necessary for the left and right prong wires to be connected exactly as they originally were, or if I can reverse them with no ill effects.  Hopefully that's a better explanation.  Thanks.

Ryan

[Hal]

OH I got it.

Yea, you can replace them without a problem.  BUT if you wanna do it properly, I THINK Blue should be "hot" - that is, the narrow plug, and the wider plug should be the brown one, which is neutral.  but it really doesn't make a differance 90% of the time.

[vanhansen]

Where is the male plug connector cut off?  Is there still a good length of cord coming out of the box or is it cut off right at the box?  If you still have a good length left, then go to Home Depot or Lowe's and buy a 3 prong male connector.  That's the easy part.  On these, I think blue is positive and brown is negative.  Look at where they are soldered on the board.  There may some indicator there like +, -, gnd.

[rspst14]

Thanks for the help guys.  There is no marking on the board to indicate + or -.  The cord is long enough that I could get away with attaching a new plug, but I might as well just replace the whole thing since I already bought a replacement cord.  I'll try what Hal suggested and see if it works.

Ryan

[vanhansen]

No problem.  Good luck.  I hope you get it right the first time.  Hooking it up the wrong way may hurt it, and you'll know by the smell.

[niftydog]

there's no such thing as + and - with AC power.

chances are as long as you get the earth lead right, the rest will be ok. However, to do it right (probably a good idea for such a potentially dangerous source of energy!) you must get active and neutral around the right way.

Does the existing cord give you any clues? Just wire up the same colours to the same points on the PCB, then make sure you wire the plug correctly.

Now, I'm from Australia, and this is the standard here. It would be worth checking it out for your own country before undertaking this;

green or green/yellow is earth

red or brown is active

black or blue is neutral

Plugs and sockets have the earth terminal marked "E" and either one of "A" or "N" marked (sometimes both)

[rspst14]

The old cord and the replacement cord have different color wires.  On the old one, green is the ground connection, and brown and blue are soldered to the board.  On the replacement, green is also ground, but the left prong is white and the right prong is black.  I have no way of knowing which wire corresponds to which prong, unless someone wants to open up an old AC powered MXR pedal and let me know.  Thanks.

Ryan

[RickL]

I just replaced the power cord in one I got recently. Looking at the back of the pedal with the power cord coming out of the top right: white wire on left, black wire on right, green wire to the case.