Hi! Several questions here. First things first: I found this IMac in the trash. yes. Crazy. so it was kind of broken, the glass panel was shattered, the hard drive was missing, the power board was toast, the power button had been glued to the metal casing for whatever reason... this iMac had suffered. that is to say, I have no idea what happened to it before I got it. Anyway, because it was waaaay better than the computer I had at home, I decided to take it and fix it. So I changed the power board, repaired the power button, and tadam, I managed to get it to start up. No image, of course, since the lcd panel was not in the best of shapes. Plugged on an external monitor, it was working fine, of course it had no hard drive so it couldn't really do anything, but at least it downloaded the recovery os. I bought an SSD (Samsung 850 Pro. I have the 840 pro in another computer, I love it), I put it inside, and.. nothing. At first I thought maybe it's because it was not in the correct format. So I went ahead and actually cloned my system on it (el capitan). Nothing. I read somewhere that sometimes the Sata cable is good enough for a hard drive but not for a SSD. So I put a hard drive inside. Nothing. Obviously, something is wrong with either the Sata cable or the Sata connector on the motherboard. Thing is, I went to the Apple Store a while back for something completly different and we talked about the "trash iMac", and at that time, about the lcd panel (I had just bought the SSD, and I hadn't tried it yet). The guy told me the problem had to be with the lcd panel, it couldn't be anything else (I suggested faulty lvds connector on the motherboard, I could see he was trying hard not to laugh at me). So I went ahead and bought a new lcd panel (second hand, tiny crack, fully working from a computer shop. Didn't pay a lot for it but still). Guess what? It was not the lcd panel. So today, I went back to Apple with my trash iMac in a plastic bag, it was really something, lcd panel was taped to the casing, power button was hanging outside the casing, stuck to it with another piece of tape... They had their fun. They had told me they could run a free diagnostic on it, so I brought the computer. Turns out, they couldn't tell me anything. So I still don't know whether the problem is with the Sata cable or with the Sata connector, if the video problem comes from the lvds connector or from the graphic card (one thing is sure by now, it's not the lcd panel, thanks a lot, Apple guy from last time, I could have spare 65 dollars), but I can't help thinking that's a lot of probkems for one computer. A Sata cable is not that expensive, but changing it means taking out the whole motherboard. And I think it's rather strange that lvds connector doesn't seem to be working, Sata connector isn't working either. Anyway, here's to my question, after this very looooong introduction. The guy I was talking to was super nice and as he could see I was genuinly interested, he showed me some schematics, and one in particular, which showed that there was a secondary Sata connector on the motherboard. I'm not talking about the legendary SSD pci port at the bottom of the motherboard, but a Sata port just behind the one which is currently in use. He told me there are two (actually three) different Sata cables for the iMac : one is the hybrid cable, that's the one I have in my computer, it delivers the power as well as Sata to the drive. One is a single Sata cable, one is a single power cable. On the schematics, we could locate the single Sata connector (its right behind the usual Sata connector, the one that "hosts" the hybrid Sata cable) but we weren't able to find where the power cable is supposed to go on the motherboard. I've been doing some research for a while on this Sata cable matter (I had my appointment at the store today, but I've been looking at the problem for about 10 days already) and I never saw anything about this additional Sata port in this particular computer (late 2013 iMac 21.5", namely emc2638, a1418, if my memory is correct). He couldn't find anything else on his schematics and documentation either, and couldn't tell me anything more about the second Sata port, apart from the fact that it's not possible to have two hard drives inside the iMac (it's not designed to host two HDs), and that it probably wouldn't work as the two Sata ports probably are used together in "some cases". Does anyone know anything about this secondary Sata port? In my situation, what would you do? Would you try to change the Sata cable (and risk messing something up with the motherboard) or would you simply drop the matter altogether, go buy yourself a thunderbolt enclosure and put your SSD inside? In that case, which one? I do realize my 850 pro is very fast. Thunderbolt 1 wouldn't be fast enough (that's what the apple guy said. I guess I believe him, a friend of mine has a thunderbolt 1 station and did some write and read tests on his ssds, the speeds were not that awesome). I was looking at the startech thunderbolt enclosure, but that's thunderbolt 1. I see OWC has launched a thunderbolt 2 enclosure for 2 disks, that would be perfect, but of course, I live abroad, and with shipping and taxes, the price is insane. I'm considering selling my 850 pro (it's almost brand new) and getting a LaCie SSD thunderbolt. It wouldn't be as fast, far from it, but at least it wouldnt be underused. Any advice on any of that, guys? I know I'm asking a lot, sorry, I probaby should have done a bunch of different threads... Thanks! Edit : seems like the guy at Apple didn't really know his products : late 2013 IMac doesn't feature thunderbolt 2, it was only introduced in late 2014 iMacs and more recent computers. So the OWC dock would be a waste on this mac.