SORRY, I mean to rectify, make good, reverse. I, as you may have guessed am not an electronics engineer, I came up with the idea for this switch and employed an engineer to design the circuit board, he also put together the first batches of assemblies which were ok, but when I tried the last couple ready for dispatch I found an earth/ground fault, and when trying to contact the engineer he was having a breakdown, so using the plans and parts list I put one together myself,( did I tell you I wasn't an electronics engineer? ) anyway it had the same fault orange LED on, I spent many days going over drawings,learning what the various components do & then testing each section of the circuit, when I put a live test on it the orange light wasn't on and the only difference was that it was sitting on top of my computer so I put it down to damp, but it is now showing a dim red LED and a bright green LED when the polarity is correct, if i reverse wire it then the red is bright & so is the green which is correct, my question is why the dim red,where is the backfeed coming from?
Ive got another thread called just a quickie, if you look on there I managed to upload some pictures of the PCB,parts list and assembled unit.

Bazzer.

 

If you got the plans, why don´t you post them here? Otherwise it is poitnless to keep debating such abstract device because we will get nowhere.

 

Ok I've uploaded the pictures here but I cant see them, I assume they go on when I submit reply.
Bazzer

 

I honestly don´t understand why is it so complicated when all it does is switch a relay when you got voltage between neutral and ground and light some LEDs.
Do you know which parts get burnt?

 

Nothing gets burned it shows faults that aren't there, ie earth light but there is nothing wrong, or a dim red LED which if it were bright would mean a reverse polarity, I've tried to make sense of the diagram but there seems to be discrepancies from the actual PCB, ie L in to transformer is FU1 but FU1 on PCB is neutral. I'm not an electronics engineer,what knowledge I,have gleaned is from working on this project & from trying to identify about a million components I bought at auction,but i can read a drawing and I've put together two of these using the diagram,parts list and photo's of a working model, I can identify resistors and their value,I can identify most components, three years looking to find what they are and what they do tends to help, but what they do in a circuit is something else, which is why the request for help.

 

Hi Bazzer,

The engineering of your circuit leaves something to be desired. It seems to have been engineered to work once, but not be repeatable in a reliable way. A good design should work over temperature, part tolerance, input signal and supply voltage variations. To be sure the circuit can be built and work many many times from "off the shelf" parts requires as much engineering as the circuit required in the first place.


Here are a few observations...

1. I'll assume the input is 240VAC rms at 50Hz coated with all kinds of higher frequency power line noise.
2. C1 & C2 seem to be too low a value. The impedance at 50Hz is 32Meg ohm. That is 240 / 32Meg is oly 7.5uA. The recommended minimum input for the 4731 is 40uA. Change C1 & C2 to 1000p, or 1n.
3. When the output of the 4731 is high it can still draw a small amount of leakage current, which varies depending on temperature and can also vary between devices. The spec says 80uA Max. With a 470K pull-up it only takes 25uA to be fully on at 12V supply bias. Change R5 & R6 to 47K.
4. IC1, Q2, Q3, Q4 are powered from C3 through R8 (1K). If all LEDs are on they draw 7.5mA, which causes a 7.5V drop across R8 and therefore reduces the supply voltage to the circuit. I would change it to 100 ohms instead.
5. I don't see how the orange LED indicates "earth fault". It only comes on if there is no voltage on line, or neutral, but then what would power TX1? How is the "earth" connection wired into your circuit?

This is just a quick check, there may be other issues as well.

Good Luck,
Ifixit

 

To all who have given advice and taken part in this blog my thanks,the problem it turned out was four diodes that were supplied wrongly & being so small I couldn't read the value even with a magnifying light, & because these were wrong it distroyed a transistor (Q1). So all working OK.
Again my thanks to all.

Barry Fulbrook.

 

A good lesson for all, thanks for posting back. Sometimes, more often than not, the problem is not as complicated as we think, and is almost too simple to see.