Recently, I was screwed by my big box of cables, when I pulled out a SATA power connector for my modular power supply, and learned very quickly that though the ports universally fit across modular PSUs, the pinouts are not actually intercompatible, and you can and will fry your hard drives.
I didn't know this; I had foolishly assumed that SATA power connectors were standardized on both ends.
Modular PSU cables never go in the big box. They go back in the PSU box if I'm being smart. Then I know which PSU they came from and can throw them out in ten years along with the PSU itself.
(I'm rarely smart and have a second big box of modular PSU cables that I maybe ought to get rid of.)
They're standardized on the device side, but not the PSU side. So always check pinout before you make the very reasonable assumption that if it fits it works
They aren't even standard on the model! One of the brands swapped pin-outs mid production run (but same SKU number and no changes in model name/packaging); and even sent back a RMA'd replacement with a different set of pinouts, but no cable, causing the user to fry their PC.
They had to make a post on r/hardware to get the brand to cover the damage, but IIRC, they never paid for data recovery services for the damaged HDDs.
I like Corsair because they at least mark the cable types on both ends; and while their PSU range vary in quality; none are trash -- Type-4 is Type-4 (or at least, I haven't heard of any reports of mislabelling on that front).
And the types in general differ in size as well. Type-4 cable physically does not fit into Type-5 PSU (well, reading this thread, this probably saved me from burned system...)
A PSU cable tester is valuable for this. They're much cheaper than a replacement PSU, and you can plug in cables wherever they fit on a PSU, and test whether the output is correct for the CPU/PCI/motherboard/SATA connector you want to plug it into. The PSU and cable might be a black box, but the output is always testable.
The motherboard cables do all kinds of different scary crossovers so never separate them, though you'll probably never have an "extra" motherboard cable in the first place.
None of the other cables bridge pins on the PSU side, they "just" scramble the pins they're attached to at the other end.
I guess, but that seems unusual. Pins are split all the time, for instance to turn a 6pin PCI connector into a substandard 8pin one, but the reverse? Merging multiple source pins into fewer output pins by shorting them together?
Visual inspection would normally catch situations like that, and then you might be able to figure out if it's okay with continuity checks and voltage checks with a multimeter on the relevant pints of the psu to see if those pins are different voltages... as long as the PSU powers the connector in the absence of load or sense pin signalling.
You don't need to be merging multiple source pins into fewer output pins; it's very normal for multiple ground pins to appear on an output connector, and for the 12V GPU and motherboard pins you see multiple output pins at 12V as well.
I too have been burned by the BBOC, although not as badly as this:
I picked out a random short ethernet cable that looked nice (it was flat) to connect my wifi AP to my router.
It took me about a month to realize my 100mbit internet connection had dropped down to about ~85-90mbit, but more importantly, transferring files between a wifi client and the wired network was also only ~90mbit.
Turned out the cable was so bad that it only connected at 100mbit...
I have now gone the other way and I actually curate the BBOC:
All cables I get for 'free' with random appliances now go straight to the bin (unless they are specialised) and I only keep cables I specifically bought and know they adhere to a standard.
That's an expensive mistake to make, though frying your HDDs is usually a lot cheaper than frying your GPU.
It's seriously annoying that this is the case though. Unless you kept the cables in the original package or in a labelled container, you cannot safely use them again if you owned more than one modular PSU.
It wasn't actually very expensive in money, because I was still able to RMA the pair of fried drives, but it did cost me $30 in shipping, a month of waiting, a lost delivery via UPS, and tons of time dealing with customer support for both UPS and Seagate to actually get a second set of replacement drives.
On the bright side, the actual replacements that eventually got to me were both 2TB bigger than the originals. They didn't tell me about this, so I'm not sure if they silently upgraded me to apologize for the wait, it was an accident, or they happened to be out of stock and just grabbed the next size up.
I had RMA'd them before I found out about the cable issue. When I was about to put in the replacements, I noticed that the SATA power cable didn't look like the others, and did some research before I plugged them in. Up to that point, I thought I just had a pair of DOA drives from the same batch or something (which I thought was unusual and quite unlikely, but not impossible).
Hmm, I wonder if this could be the source of an issue with my gaming PC that's using some super budget SATA3 SSDs connected by miscellaneous cables to my relatively newer psu and mobo. Everytime I turn the PC on, it seems to fail to recognize the boot drive and won't POST, but then after force shutdown and restart it succeeds. I think the power cables did ship with the PSU though, the SATA cables came from wherever
Yeah, same cables but different specifications is a danger; I've got old HDMI / DP cables for example, they're backwards compatible and still fit into modern systems of course, but won't do 4K / 144 hz (or whatever).
One day I'll sort the box out. There's even SCART and PATA cables in there, as well as my old diskette holder.
...I should try and build myself a vintage PC sooner rather than later. Mind you, my dad got rid of all our old shareware diskettes years ago, unfortunately.
I hope you never have to work with serial D9 cables. The variation of pinouts for legacy equipment is massive! Pretty sure every theoretical variation became some standard.
I'm lucky so far that I've kept all the cables from all the PSUs I've had, and they matched in colour per PSU, so I've never had the temptation to pick a random one. Phew, saved by autism.
I didn't know this; I had foolishly assumed that SATA power connectors were standardized on both ends.