Replacing an Amplifier Power Supply Question

[Jez Corbett]

The internal power supply in a speaker amplifer I own recently died, and as advised by the manufacturer I bought a replacement from them.

This is it:

https://nordacoustics.co.uk/product/hyp ... pair-only/

Customer support suggest its totally fine for me to replace this myself but electronics repair is very much not my expertise and looking at it I'm scared I'm going to electrocute myself touching one of these capacitors or something.

Can anyone here give me a second opinion?

[James Perrett]

I've built a Hypex based amp using a similar power supply.

The first thing to do is to completely unplug the amp. Then leave it for a few minutes to allow the capacitors to discharge. You should then be able to disconnect all the cables - pull on the connector bodies, not the wires. The white connectors may take a bit of pulling as they are designed to not come apart easily. The fixing screws can then be unscrewed and the board should lift off.

Fit the new board by doing the reverse of the above procedure.

I'm fairly sure that you can't plug anything in the wrong way round or into the wrong connector unless you really force something and break it.

[ef37a]

As James says, you should be fine if you take care and work methodically.

You could wear a pair of blue "mechanics" gloves but don't then think you are immune! They will stop 300V or so from a touch but a bit of spiky solder could still get you.

I would also say, because of the 200V rating of those 820uF caps they must be in series and that means there must be some splitter/drain resistors.

Dave.

[Hugh Robjohns]

Customer support suggest its totally fine for me to replace this myself but electronics repair is very much not my expertise and looking at it I'm scared I'm going to electrocute myself touching one of these capacitors or something.

This isn't 'electronics repair, it's just swapping out a module — literally plug and play!

The new module will not be charged, so no risk of electrocution there, and the old one will lose its charge completely within a few minutes of being switched off, so no worries there either.

Plus, Nord wouldn't say it was customer replacable if there was any risk. Their insurers wouldn't let them!

So, my advice is to find yourself a clean, well lit and uncluttered space to disassemble the unit where you won't be disturbed. Take your time, and take lots of pictures as you progress so that you'll have references for reassembly.

Hopefully the connectors are all different so will only fit in one place and one way around, but the photos will help you remember what goes where.

Most connectors have some kind of latch or clip to hold it in place, so check before trying to pull apart. You might need to release the catch with a small screwdriver while easing the plug out, for example.

With the old board out and new one installed, go and have a cup of tea.... and then come back and check everything is back together correctly, checking against your photos of the original installation. All the securing screws in the right places and tight, all the connectors.

When you're happy, reassemble the cabinet and fire the thing up.