The fact that the DC-DC converters are showing voltage means they are probably working. If they were shorted you would see 0 volts on that die. My guess is nothing is pulling power from those particular ones, that's why they are cold.
Ergo, chip problem. You can try a low frequency on those dies, see if they respond to that.
I tried the lowest voltage and the lowest frequency and they are still dead. Been like this ever since I got the unit. Figured it might of been an easy fix.
I got 2 dies like this from day one .....nov 2014 1st batch units are notorious for having at least 1 dead die...but it was usually 2 dies 1 dead and 1 slow it seemed back
when folk were yelling and burning torches on knc forums to no avail
but yeah me too 2 dead dies orig unit
got a badly abused used titan in march when we all thought all them new bigger scrypt miners were coming out (volcano/alpha/flower/etc) so figured at the time
my units might last till may and paid appropriately ...not sure if ebay search goes back that far but the problems with firmware and other issues they were being dumped
my 'regret' is I could have gotten a titan cube like may 2015 or something for 500 usd buy it now...passed i mean LTC was 1.30 or so.....duh....my hope is the same NOW
with the price....of LTC say as an example.....if price would pop.....we would be golden
anyway the 2nd used unit I got in March was run in hot outback of Australia no a/c (or hell it could not keep up) in an apt.and had blown thru 2 or 3 psu's due to heat
the paint on the cube ...looks like the hood of an Arizona car parked in the sun for 8 years..sheesh (very retro looking thou I must say..you can see the paint speckles on
the top from the heat..I kid you not)
that titan unit complete still runs 350mh full out balls to the wall....my orig 'babied' titan unit...has the orig 2 dead dies and 2 dies on a cube 1 set to 250 the other to 225
so go figure it is all about the dies...the 1st run titans had lots of bad dies....it is the luck of the draw imho some got Titans back then with 1/2 the die dead
got the re-paste i got with fan and heat sinks (Swedish guy mod video on this thread) stuff I could try ..but I've lost 5mh since these Nov 2014 units were gotten .....both of them nov units 2014..that is what now 14 months on the orig miner..yesterday
So am not gonna sweat it and burn a cube (yet) There will come a time when I will probably have to do the re-paste and mods etc..but only losing 5mh from 650mh to 645mh it is
JUST NOT worth mucking with them yet (knock wood)
anyway again imho the reason KNC overclocked these beasts 2x (orig 250mh machine..then 300mh firmware when late by months...then bad dies changed firmware to make them use the 325 setting to 350mh units...so they could get out of masseve RMA issues....and of course 2 prog to 1 plug adapters so they STOPPED catching on fire
).....so again ...anything anyone can get over 300mh is a gift...so think long and hard on if you really want to muck with a cube that is working overclocked 3/4 of the dies.....you could kill the works (being a coward seems to work for me so far.....)
Anyway to me the risk/reward is just not worth it..then again I have 2 Titans and one was way way golden at 350mh so ......i have some slack for my ego on all this....