Hi guys. My 1st post here, be gentle with me
A few months ago I bought a Chinese 852D+ rework station for carrying out smartphone board repairs. I'd heard stuff about poor build quality on things like this so first thing I did was open it up and check to see if it was fused and earthed. All looked ok to my somewhat untrained eye, with proper fuse (albeit in the neutral line only), the case had a clean earth connection and everything looked neat and tidy. Switched it on and everything seemed to work as it should so I put it to use straight away. So far so good ...
A little while ago the soldering iron blew and I bought a replacement element. After fitting it I checked to see if the tip was earthed - something that I'd not thought to check before - after all it says "ESD Safe" on the front of the controller so it must be earthed, right? Er, no. The iron itself is ok - it has a 5 pin connector and pin 3 connects to the tip. But pin 3 on the controller does not go to ground. With the iron connected I measured ac voltage across the tip and the grounded case - I get 26.8 volts! That's with the unit connected to mains with nothing actually switched on - the tip voltage does not change when the iron is switched on.
I had a look inside again. Turns out the only thing that's earthed is the case, and the PCB and everything else is isolated from it. One of the ICs on the PCB has a pin marked 'gnd'- I toyed with the idea of simply running a wire from that pin to the earth tag on the case - but I don't know enough about these things to judge if that would be a wise move? A schematic would help but I've been unable to find one, for this or any other 852D+ station. There is no hint on the outside of the device nor on the accompanying esoteric 'manual' as to who the manufacturer is - but the PCB is evidently made by YouDe, a company I suspect is responsible for producing many of the clones out there.
An obvious course of action would be to junk the thing and spend more money (a lot more money) on a more respectable unit - but surely it can't be too difficult for someone who knows what they're doing to modify this one so it works properly? I'm competent with a soldering iron but I don't have a clue about circuitry - can anyone give me some simple guidance? (Like am I risking anything by connecting that 'gnd' pin to the earth tag ... )
I should mention that I've used this device, soldering iron and hot air blower (also recently discovered has >10VAC at the shroud) to replace damaged or missing SMD / BGA components on iPhone 4 and 4S logic boards and restored them to full working order - I've done six to date. And surprisingly I haven't actually destroyed a board yet (I'd find this surprising even if my rework station had been behaving normally!) So maybe I should pretend I haven't noticed anything out of the ordinary and carry on regardless!