Not doing the math, and setting shit on fire.

K

KD5ZXG

Gawd
Joined
Mar 24, 2017
Messages
745
I was pulling 750W from the wall, and my 850W Toughpower Grand was handling it fine.
Just running a bit toasty, and I'm thinking closer to a 50% load would be more efficient...

So, I gank all my mixed bag of AMD/NVidia from this rig and replace with Qty8 1050ti.
That got my power down to 550W. I was dumb and happy and dumb and what's that
strange burning smell?

Well, turns out I totally melted one of the 6pin peripheral sockets on the supply, and
another showed signs of nearly getting zorched as well. Didn't exactly kill the supply,
just ruined one connector and filled the house with stinky burning plastic smell.

Just cause you CAN power four risers from the same SATA daisychain power cable
don't mean you ever should. Three is working right now, but I probably need to pare
it down no more than two...

See, I got these fancy new 6pin risers that run on 12V only, with a little DC-DC buck
to provide 5V. Which is probably exactly what you want and need for 6pin 12V supply.
Not what you want for SATA power...

The peripheral connector does not dedicate three of six pins to 12V. No, only seems
to give one pin to 12V. The rest are 5V and GND. Since 6pin risers don't use 5V from
SATA adaptors, four 1050ti's pull every bit of 275W from just ONE 12V peripheral pin.
And of course, that's the pin that burns...

The moral of this story is never power more than two 6pin risers loaded with1050ti's
from one SATA peripheral cable. Maybe three is OK if you got 4pin molex risers that
accept some current on the 5V wire as well.

If your GPUs won't accept power from the top. Plug a real 6pin PCIe cable directly
into the riser. This gives three wires and three pins of 12V at both ends of the cable.
 
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I watch a lot of videos on Utube when I first decided I wanted to get in to this. And back then a lot of videos stated not to power more then 2 risers off of one sata peripheral cable. So even the sata peripheral cables I have, there's 4 sata connectors. I will only use 2 of them.Just think 12 card rigs with 12 risers. That's 6 sata peripheral cables.
 
People still use ATX psus for mining eh... time to step up to server psus.
 
Yes is there not a guide on here already I'm how to use the server psus that are dirt cheap with the pcie power breakout boards? If not maybe someone should make one
 
boushidosan said:
Yes is there not a guide on here already I'm how to use the server psus that are dirt cheap with the pcie power breakout boards? If not maybe someone should make one
Click to expand...
I still have my old ones from way before breakout boards where I soldered onto the PSU and hot glued the solder parts to help seal them on. At some point I"m going to get around to converting over to those breakouts.
 
OP...weird format
Iambic pentameter?
Goofy power stuff
 
While these Thermaltake supplies continue to operate just fine, more or less...
I'm beginning to suspect something wrong with that particular modular location.
I just had another brand new one burn up with only 2 gpu load on that plug.

Didn't turn to complete charcoal this time, and most of the plastic is still there. But that
charred connection won't conduct well enough to run even 1 GPU load with stability.
Crash in less than 10min, so that peripheral cable is basically of no use anymore.

While an adjacent and supposedly identical peripheral connector shows no sign of any
trouble at all. Indeed with the last supply, handled 4 GPUs with only slight discoloration.
and the new supply with 2GPU load shows no discoloration.

So just seems a little too much coincidence that now with 2GPU load, the same pattern.
One (same location as before) has begun to burn, while its neighbor looks just like new.

I dunno if its poor soldering, or maybe a location that doesn't get enough fan. I will be
taking the lid off (further void of warranty) at least one to find out whats really going on.

5A (60W) per GPU might just be asking too much, but you would expect identical
modular connections on the same supply with identical loads to burn-up identically.
 
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TI just posted a rather interesting diatribe about 80+ platinum reference design.
Fairly complete: with schematitcs, theory, and math if you care about math...
Do at least view the graph regarding 120VAC vs 220VAC performance.

www.ti.com/tool/TIDA-01501

Slightly more math than I care to understand. As I am just setting stuff on fire.
No, I didn't have anything to do with testing this one. Far as I know, it doesn't
even catch fire all that well. Keep away from my desk and might stay that way.
 
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