PELLERIN MILNOR CORPORATION
2.
Determining Whether to Install or Omit the Regulating Resistor
The purpose for the regulating resistor is to ensure that the power supply has a certain minimum
load. This is necessary for the power supply to be able to maintain the specified output. Machines
that use this power supply have processor boards with Milnor part numbers beginning with
“08BSP...”, “08BN...” or “08BH...” You will need to read the part number printed on your
processor board (usually on a sticker affixed to the board). If the part number begins with
“08BSP...”, your control system uses peripheral boards connected to the processor board via a
serial interface. In all probability, the regulating resistor should not be used because the peripheral
boards provide sufficient load (see Section 2.1). For the other controller types, the resistor is
needed but may or may not already be present on your machine (see Section 2.2).
2.1.
Machines With “08BSP...” Processor Boards
—On these machines, omit the
regulating resistor. However, in rare cases, a machine with this type of board may have too few
peripheral boards to provide a sufficient load for the power supply. If, after replacing the power
supply, your machine experiences resets (as explained in Section 4), contact Milnor Customer
Service to determine if the problem is likely due to insufficient load on the power supply. If this
is determined to be the case, you will need to install the resistor, as explained in Section 3.
2.2.
Machines With “08BN...” and “08BH...” Processor Boards
—The regulating
resistor is built into newer processor boards. If the processor on your machine does not have this
resistor on board, install the one included with the kit, as explained in Section 3. Otherwise, omit
the resistor. The following are three ways to determine whether the resistor is present on your
machine. Because it is very important to either install or omit the resister as appropriate, double-
check by using at least two of the methods explained below.
1.
By observation
—You may be able to identify the regulating resistor on your processor board
by comparing it to one of the pictures in Figure 2.
Figure 2: Processor Boards With Regulating Resistor On Board
Processor Board 08BN785AT
Processor Board 08BN788AT
Processor Board 08BH18EPBT
Legend
1.
Regulating resistor
2.
Processor board part number
3.
Processor board revision (rev) level
.
