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Hello everyone,

One of the Avalon molex connector got burned by the PSU.

Does anybody know what is the model of the Avalon 741 molex connector? and how to repair/solder a new one into it?

https://dl.dropboxusercontent.com/s/sk3244bz3l12yr1/left_hashboard_burnt6pin2.JPG


Thank you!

Uhh, that's badly burned.  :-\

See my post here --> https://bitcointalk.org/index.php?topic=3121002.msg32670392#msg32670392 (https://bitcointalk.org/index.php?topic=3121002.msg32670392#msg32670392)

Thank you HagssFIN, I will reach out to lightfoot.

Crunchy. I'd recommend sending it in for repair. The trick with these is you need to have preheat to warm the board enough to get the component off without damaging the vias. Doable, but requires some tools.

lightfoot, is this a common problem with the HP common slot PSU's?  I had the same problem recently using Deepinthemines breakout boards with 750w PSU's

Its MOLEX, LLC part number 0039301060

digikey has it: Digi-Key Part Number WM1353-ND

https://www.digikey.com/product-detail/en/molex-llc/0039301060/WM1353-ND/561080

I took apart my avalon 741 and removed the EBE5 pcb that has the molex connectors on it so I could work on it, the black plastic from the male connector had melted onto the female connector.  Put a hairdryer to it to soften the plastic a bit and was able to clean it out using needle nose pliers and a pick.  Anyway I am able to plug the PSU back in but I will be replacing this as soon as my order from digikey arrives.  

Tools:
Hakko 808 de-soldering station
Weller WES51 soldering station
Hobby creek helping hands holder
patience

I am switching out the HP common slot 750w with the 1200w's.  These pull 900w on 110v lines.  I was using the deepinthemines HP 1500W/1200W/750W DITM-W-12-75 plain breakout boards wired up with 16GA cable one 12V cable and one Ground cable per molex connector.

heres the damage:

https://imgur.com/a/rQjNM

JHenry01
Think your main problem is your cabling and not the PSU.
Looking at your pics you are using a single wire of 16awg for ground and supply to a single pin of the molex connector
The amps should be spread across all 6 pins of the molex connections with 6 x 16awg to stop it from overheating the wire.

ok, starting to crimp some more cable right now.  I've got 12 psu's to rewire :-[

Does anyone have one of these modules?  I could use one.

https://i.imgur.com/W3cTrLx.png

Not to rub it in but... *why* on earth would a person wire these plugs using only 1 wire pair? Did they seriously think that it would work and all those other connections are just unneeded spares?http://www.sherv.net/cm/emoticons/blue-face/blank-expression-smiley-emoticon.png (http://www.sherv.net/) http://www.sherv.net/cm/emoticons/hand-gestures/3d-smiley-says-no-way-emoticon.gif (http://www.sherv.net/)

he had a bad day I guess

The root of the problem is either wires that are too small to the plug, or a power supply that sags under load. The sagging thing is interesting, if the voltage drops to 10v, the current has to go up to maintain the load. Since P=IE (mmmm, pie!) lower E=higher I. Which causes more heat, which increases the resistance of the pin which leads to more voltage dropped and the usual burning.

I use the Emerson supplies myself with 16 gauge wire plugs. No problem there. In terms of getting the plugs off I find that using some good old rosin/lead solder on the pins first (to allow with the ROHS) REALLY drops the melting point a nice bit and makes it easier. You can also get some chipquick. :-)

C

Heh. I remember someone who actually chained a second BFL single miner onto the second plug, and wondered why it toasted the first plug. Same engineering failure as the Kansas City walkway collapse.

(ie: oops)

To be more serious, I'm guessing he had all three plugged in. The reason one toasted is that heat thing: Remember as the pins get hotter the resistance goes up. Which means it drops more voltage which means more heat. It's a positive feedback loop, and why you see one pin incinerate, then the second, then the third. With multiple plugs one burns first then the second then the third.

C