Tech Sheet

FOR SERVICE TECHNICIAN’S USE ONLY
12
COMPONENT FROM TO VOLTAGE RESISTANCE NOTES
UI/Display PCB Main Board - J13 Main Board - J13 Pin 1 = +5 VDC
Pin 2 = TX BUS (MAX 5 V)
Pin 3 = RX BUS (MAX 5 V)
Pin 4 = GND
Pin 5 = -7 VDC
Pin 6 = DATA OUT (MAX 5 VDC)
Pin 7 = DATA IN (MAX 5 VDC)
Pin 8 = CLOCK (MAX 5 VDC)
N/A Connector going to Display
PCB. Supplies circuit
ground, +5 VDC, -7 VDC and
transmission lines.
NOTE: 12 VDC is provided
when measuring the differential
between +5 VDC and -7 VDC.
EV1, 3-Way Valve L1 Junction Block Main Board J1-2 120 VAC 458K ohms Drain Valve is grounded to heat
exchanger support.
EV2, 2-Way Valve L1 Junction Block Main Board J1-1 120 VAC 444 ohms Water Valve is grounded to
upper reinforcement, lower and
upper Main Board cover, and
heat exchanger support.
Component Testing Chart
Unplug coffee system or disconnect power before performing the following checks:
■ A potential cause of a control not functioning is corrosion on connections.
Observe connections and check for continuity with an ohmmeter.
■ All tests/checks should be made with a VOM or DVM having a sensitivity
of 20,000  per volt DC or greater.
■ Check all connections before replacing components, looking for broken
or loose wires, failed terminals, or wires not pressed into connectors far
enough. Damaged harness must be entirely replaced. Do not rework a
harness.
■ Resistance checks must be made with power cord unplugged from
outlet, and with wiring harness or connectors disconnected.
Do not continue with the diagnosis of the appliance if a fuse is blown, a circuit breaker is tripped, or if there is less than 120 + 10%/-15% volt power supply.
The coffee system must be unplugged or the power disconnected when measuring resistance.
When checking for proper voltage, complete the following steps:
1. Disconnect power.
2. Connect voltage measurement equipment.
3. Reconnect power and conrm voltage reading.
4. Disconnect power after performing voltage measurements.