An SCS 440 or 450 is a simple system: a console, a cable to the hitch, a cable from the hitch to the valves and meter. When sections drop out, flow reads zero, or the console resets when the pump loads up, the fault is in one of four places, and the hitch connector is the first place we look. The trick is using the console's own counters to split the problem between the two cables before you buy either one.
1. How it is cabled
The console cable plugs into the back of the console, runs through the cab, and ends at a 16-pin connector at the tractor hitch. It carries the boom section outputs, the control valve drive and the three-wire flow meter circuit. The machine cable mates to it at the hitch and runs to each boom valve, the motorized control valve and the flow meter; on a six-section system the manual assigns Black to valve 1, Brown to valve 2, Blue to valve 3, Black/White to valve 4, Brown/White to valve 5 and Blue/White to valve 6. The speed sensor has its own cable into the console. Power is two wires straight to the battery, white to negative and red to positive, never to the starter. The manual says not to modify or lengthen the three-wire speed or flow cables.
2. Which symptom points where
- One section dead, the rest work — that section's wire in the machine cable, its connector, or the boom valve. Swap the dead valve's plug onto the next section's connector: if it runs, it is the wire; if not, the valve.
- All sections dead — console power or ground, the fuse on the back of the console, the BOOM and MASTER switches, or the console cable. The manual's first check for a dead console is the fuse, battery connections and POWER switch.
- Flow reads zero but the meter spins — the flow signal wire, the sensor's power or ground wire, or the sensor. The manual's order: check the flow cable for breaks and shorts, clean the meter, replace the transducer. See Raven rate reads zero for the speed side.
- Console resets under load — voltage drop on power or ground, a corroded battery clamp, or a cable pinched at the cab door. The console loses just enough voltage when the valves and pump pull current.
- Rate hunts or the control valve runs one way — control valve wires, the polarity jumper, or the valve motor. The manual's test: MASTER on, RATE in MAN, press INC and DEC, read voltage at the valve connector and watch the shaft. Voltage and no motion is the valve; no voltage is cable or console.
3. The console's built-in cable test
The SCS 450 manual (016-0159-831) and the SCS 440 manual (016-0159-822, "Testing Flow Meter Cables") use the same idea: the console puts +5 VDC on the flow meter cable and counts pulses, so you can fake a pulse with a jumper and watch the counter.
- Flow cable — unplug the cable at the flow meter and hold the connector with the keyway at 12 o'clock. Set METER CAL to 1, turn the boom switches on, and short the 2 o'clock socket to the 6 o'clock socket with a paper clip in a short-no short motion. TOTAL VOLUME should go up each time you make contact, and a meter from 2 o'clock to 6 o'clock should read +5 VDC. If the count climbs, every wire from the console to that connector is good and the problem is the sensor. If it does not, move back to the next connector toward the console, which is the hitch, and repeat.
- Speed cable — same test with SPEED CAL at 1000, shorting the 10 o'clock and 6 o'clock sockets. DISTANCE should climb. If every cable passes, replace the sensor.
- Put the real cal numbers back when you are done; our catch test article covers re-checking METER CAL.
Some call this the "9 volt test" because you can pulse the signal wire from a battery instead. The manual's method uses the console's own 5 volts and a jumper; use that one, and do not put 9 or 12 volts into the signal socket.
4. Split it at the hitch
The hitch connector is where the two cables meet and where they fail. It hangs over the drawbar, drags through mud and catches every fertilizer drip. Unplug it and look at the pins first. Then use it to split the problem.
| Test at the hitch, console-cable half | Reads | Meaning |
|---|---|---|
| Jumper flow signal to flow ground | TOTAL VOLUME climbs | Console cable good; fault is in the machine cable or meter. No count: console cable or console |
| Voltmeter on a section output, boom switch on | Battery voltage | Console cable good; fault is downstream. Zero or low: console cable, console or switch |
| Voltmeter across the console's red and white battery leads, valves on | Well below battery | Voltage drop; check battery clamps, ground and the power-lead run |
Which pin is which: use the pin diagram in the Raven manual for your console and cable revision. We do not print a 16-pin pinout here because we could not verify one against the manual, and a wrong pin number is worse than none. If your diagram is missing, call and we will tell you which pin to probe.
5. The parts, when it is not the cable
| Fault found | Part |
|---|---|
| Section wire good, valve dead | Boom valve motor assembly or single-section manifold boom valve |
| Flow cable passes, no pulses from meter | Gear tooth flow sensor or external high-pulse sensor assembly; RFM 200 cable kit 117-0159-441 |
| Control valve gets voltage, does not turn | 1-1/2" standard control valve or 1" standard control valve; or send it for a Control Valve Check Out |
| Console cable open or chafed | SCS 440/450 console cable, built to length |
| Machine cable open or chafed | SCS 440/450 machine cable, built to length |
| Not sure which | Cable Check Out bench test, $75 |
6. Doing it
- Power off and depressurize before you unplug anything at the boom; rinse the connectors and wear gloves.
- Clean the hitch pins with contact cleaner and a brass brush, then meter them. A pin that looks clean can still read several ohms.
- Re-pin a single bad contact; replace the cable if the jacket is cut at a flex point or more than one wire is gone. The full method, with wiggle and voltage-drop tests, is in Is it the harness?.
- Valve-side problems are in boom section won't shut off or open; meter problems in RFM flow meter erratic, low or zero.
Not sure which cable it is? Send a photo of the hitch connector and tell us which sections are affected to sales@spraycenter.com or call (509) 838-2209.
SCS 440 / 450 16-pin console connector pinout
This is the 16-pin round connector on the back of the Raven SCS 440 and SCS 450 consoles, as wired in our console and machine cables. Pins 7, 8 and 9 carry booms 4–6 on the SCS 450 and are empty on a 440. Use it with a meter to check continuity end to end, or to confirm the right wire is reaching a valve or the flow meter.
| Pin | Wire color | Function |
|---|---|---|
| 1 | White | Ground |
| 2 | Brown | Boom 2 |
| 3 | Yellow | Increase (control valve) |
| 4 | Green | Decrease (control valve) |
| 5 | Blue | Boom 3 |
| 6 | Black | Boom 1 |
| 7 | Black/White | Boom 4 (SCS 450 only) |
| 8 | Brown/White | Boom 5 (SCS 450); pressure sensor signal on SCS 460 |
| 9 | Blue/White | Boom 6 (SCS 450); pressure sensor ground on SCS 460 |
| 10 | Orange/White | Remote master (SCS 440 / 450); pressure sensor power on SCS 460 |
| 11 | Shield | Flow meter ground |
| 12 | Black | Flow meter power (+5 V) |
| 13 | White (red on newer cables) | Flow meter signal |
| 14 | Orange | Remote power |
| 15 | White/Black (SCS 460) | Not used on SCS 440 / 450; used on SCS 460 |
| 16 | Red | Console power (+12 V) |
SCS 460 differences
The SCS 460 adds a pressure sensor input on the same 16-pin connector. On a 460, pins 8, 9 and 10 carry the pressure sensor instead of booms 5–6 and remote master, following the same three-wire convention as the flow and speed cables, and pin 15 is used.
| Pin | Wire color | Function on SCS 460 |
|---|---|---|
| 8 | Red | Pressure sensor signal |
| 9 | Shield | Pressure sensor ground |
| 10 | Black | Pressure sensor power |
| 15 | White/Black | SCS 460 only |
Flow meter and speed sensor 3-pin connectors
Both the flow meter and the speed sensor use the same 3-pin round connector (flow is the female lock-nut end on the console side; speed is the male end). Power is +5 V from the console; signal is a pulse the console counts.
| Connector pin | Marking | Wire | Function |
|---|---|---|---|
| + | PWR | Black | +5 V power from the console |
| − | GND | Shield / drain | Ground |
| S | SIGNAL | White (red on newer cables) | Pulse signal to the console |
Pinout from Spray Center Electronics' own cable drawings (16pin440, rev 1.0). Older Raven cables use white for the signal wire; newer ones use red. If your cable has been repaired, verify colors with a meter before trusting them.
Spray Center Electronics stocks Raven SCS parts and builds SCS 440/450 console and machine cables in Spokane, WA. Test procedures here come from the Raven SCS 440 and SCS 450 Installation and Service Manuals; pin positions for your cable come from the diagram in your manual. Send a photo of the connector and we'll match it before you order.