| Electronics > Repair |
| Monitor Speaker tripping the mains circuits (UK) insulation test ok, what next? |
| << < (2/2) |
| Reprobyte:
Sorry I did mean that, I selected the wrong one in the box my mistake there it was not the lighting it was the sockets my bad there. Yes they do use switching power as far as I am aware. It's not something that happens every time, its more of an every so often thing, but its done it with signal connected and disconnected. Thanks I will do some testing on the continuity of ground, didnt think of that, appreciate the advice here. |
| themadhippy:
--- Quote --- will do some testing on the continuity of ground --- End quote --- As its an overload device and not the rcd thats tripping i'd lean more towards a live-neutral issue |
| Reprobyte:
--- Quote from: themadhippy on July 10, 2024, 08:44:11 pm --- --- Quote --- will do some testing on the continuity of ground --- End quote --- As its an overload device and not the rcd thats tripping i'd lean more towards a live-neutral issue --- End quote --- Thanks for the advice, what is the best way for me to work out if that's the case here? |
| shakalnokturn:
To second themadhippy, this shouldn't be an earth fault, i'd check if the offending speaker has a moulded input EMI filter, I've seen those have intermittent shorts on a couple of occasions. If supply is not SMPS the transformer could be suspect too, generally check for pinched or stripped wires. Tie your continuity tester to the mains inlet, give the speaker a few jerks / slaps. If no luck open it an wriggle things around, apply a little pressure here and there. |
| Gyro:
It was probably a mistake for me to include the afterthought of the signal ground continuity test (simple and quick though it is). I agree with the others, it is a L - N surge current or intermittent short fault, as I explained, I think the RCD trip was due to it being right next to the MCB that tripped. Presumably the speakers have some internal mains supply fuse. If this isn't blowing (it clearly isn't) then any intermittent short would be upstream of that - but I don't think it is, intermittent shorts rapidly turn into hard faults. They will definitely be visible on inspection if [they are it is] tripping a 32A MCB*. Again I think you need to do an internal comparison. As I mentioned earlier, my gut feeling is that something is going on with the (SMPS) input surge limiting NTC thermistor. Maybe it failed on that speaker and the previous owner linked it out. Most SMPS faults (transformer etc) will result in a 'catastrophic' component failure rather than an intermittent. I'm sorry, but I don't see any alternative to unscrewing the rear panels and inspecting. If you post photos of both speaker internals then we have a better chance of spotting something. Edit: * Being in the UK, you also have a mains fuse in the plug. |
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