Quote from: mattie on October 27, 2014, 11:31:33 PM

Any tips on how to get disabled dies/cores enabled again on neptunes.
Got one neptune which is very stubborn even after upgrades / downgrades reboots the die's still won't come up.

--SNIP--

Haven't had the chance yet to power down the full cubes yet as they are on a remote site.
Know previously we had a script to enable all cores again with a reboot by using a script on jupiters.
Not sure if there is any for neptunes?

It is my experience that the DC/DC on a Nep can lock up.
This requires you to power cycle the ASIC PCB to recover the DC/DC converters.
I have OCCASIONALLY had success with a "Triple waas with a full twist"
(hunt thru my posts if interested)

I think the lock up and failure to recover are related to the way kfc powers the communications.
They changed the communications circuitry on the 20nm products.
This change IMneverHO is part of the problem.

First they blamed the GE VRMs and switched to Ericsson.
The new ones don't sing loudly, they go silent and cold instead.

If a cube works for a while then develops issues over time,,,
Check the heatsinks (learn how if you must, takes less time than an RMA)
My Nep instability is usually temp related.

The irony, IMneverHO, is they could have used 12 VRM per PCB and shipped 4 ASIC Neptune.
Their decision not too requires 25% more ASIC to fill existing orders.
An ASIC must cost lots less than 8 VRM else they would have...
kfc does an 'own goal' at everyones expense.

YMMV