Post
Topic
Board Hardware
Re: Avalon2 based miner from Technobit - HEX16A2
by
klondike_bar
on 08/02/2014, 16:04:57 UTC
Hi

I have a big problem.
I have 5 miners and all of them work fine IF a let them work one by one...even two together work fine.
BUT.....

If i want to let 3 miners work together, the PSU crashes.

The miners, the hub and the MR-3020 are ALL conected to the same PSU-Molex cable-tree.
The PSU has 550W....

What can be the problem?

Can it be that the PSU is too old even it has NEW 550W?

Pls help me ..... i cann't solve this problem
what is the rating AMPS of PSU 12V rail is it a single one?

PSU-Model: pentium iv & pfc model lc6550G version 2.0

MAC DC OUTPUT:
+12V1 -> 16A
+12V2 -> 18A


I made a shortcut betwen the green and black cable to turn the PSU on without motherboard.
So
1. Chosse a single rail PSU
2. When board is OC-e it is eating about 9.5 Amps
So if i were on your shoes i will connect just two boards to this PSU when i am absolutely sure that each board is connected on a separate 12V rail. Does this explanation clears up a mastery crash;)
And do not push it to much magic smoke will come out sooner or later. I am not joking here i am serious

So you say that the PSU is too poor to run more then 2 boards at once?

Will a new PSU work better and how much power do i need to run all 5 together?

okay, its not just the PSU's fault, its also yours.
1) when you say you run 2 or even 3 boards plus other components on a single 'molex tree', are you referring to a singlular cable with multiple 4-pin molex connectors along its length?
if you are - thats problem #1. There is only a single 12V lead in that cable, meaning two things:
a) it will be tied to only one of the PSU's 12V rails. lets assume the lower, 16A: 16*12=192W. This is barely enough power for 2 units at full speed/overclock.
b) check your cable. its unsafe to pull more than 60-100w through a single 18AWG cable like your PSU probably has. You can easily melt the plastic and start fires.

2) In order to properly power more than 2 of these on your supply, you need to identify which rail supplies which 12V power cables. Usually 1 rail is dedicated to the 4/8-pin square ATX mobo plugs and the other for the PCI cables and molex accessory cables. using the above math, you can assume you have 2 rails each capable of 2 devices. You 100% will not be able to fit 5 without massive underclocking of 3 of them.

my advice: snip the heads off the PCI and ATX mobo connectors, and use a wire pair per device.