770ED error code 001-- 96--3812

[kev.g]

Hi,This is my first post so please forgive any rule violations.
I have just bought 6 770 ed's off ebay ,2 work fine and I have installed XP on them with no problems ,one even went through the installation with only 64 mb ram because I forgot to swap it from the first machine before I started.
One machine gives me test errors for the system board of "DEV 001 - ERR 96 - FRU 3812".
I looked in the service manual and can't see any reference to ERR 96 any body know what it is please?
FRU 3812 code is for FAN as first faulty item and DC-DC as second faulty item.
The fan comes on loud as soon as power is switched on and then runs quietly ,so does that mean that the DC-DC is the real culprit here? And am I right in guessing that DC-DC is the power input board?
Thank you in advance for any help which I feel sure I will receive.