NuForce Ref 9 V2 Upgrade

Nuforce V2 board upgrade (4/19/07)

This instruction is pertaining to the F15HER3D version of Nuforce V2 amplifier PCB
(Printed Circuit Board).
The upgrade is essentially a drop-in replacement of the existing 9.02 PCB (Printed
Circuit Board). On the V2 board all of the necessary power supplies (a separate power
supply for the input driver) are on the single PCB, therefore, the external 24V DC/DC
converter as part of the original SE package need not be used. A new Zobel Filter is
included for soldering to the speaker terminals.
The power supply (SMPS) should be upgraded as well to change Over-Current protection
threshold to 500W in order to reliability power-up the V2 boards.

Upgrade procedures for Ref 9 and Ref 9SE:

1. Unsolder the speaker cables and the output capacitor filter on the speaker terminals.
To prevent overheating the Eichmann binding posts, please connect a speaker cable to
the binding posts to serve as heat sink.
2. Unsolder and remove the input wires on the RCA and XLR.
3. Unplug the Red/Black DC power cable from the board. For the 9SE, remove all
other power wires as well (black, blue, and brown wires).
4. Remove the 6 screws on the PCB, and 3 heat sink screws on the bottom (use #3
Philips screwdriver bit) and remove 9.02 PCB completely. Use a paper tower to
clean up the heat sink compound on the heat sink and the bottom of the chassis. The
removed, functioning board should be kept as spare parts for Ref9/RefSE
replacement or repair.
5. On Ref9SE, an additional 100 Ohm resistor is required to be soldered between the
negative of the RCA (outer connection, i.e. shell) to the signal ground on the XLR.