Network 8000: Modem Troubleshooting
LESSON SUMMARY: This lesson is designed to assist the user in troubleshooting a satellite that is experiencing communication failures with the central computer.
Special Tools Needed: Digital Multimeter, Phillips Screwdriver
⚠ CAUTION: THIS LESSON MAY INCLUDE INSTRUCTIONS TO TEST HAZARDOUS VOLTAGES (120V-240V) THAT CAN CAUSE SERIOUS INJURY OR DEATH. IT IS RECOMMENDED THAT A LICENSED ELECTRICIAN BE CONTRACTED TO PERFORM SUCH TESTS.
🛑 STOP: ALWAYS TURN OFF THE POWER TO THE SATELLITE BEFORE REMOVING OR INSTALLING ELECTRONIC COMPONENTS.
The Modem in a Network 8000® satellite is responsible for communicating with the central computer. If the Modem is damaged or is not functioning properly, communication with the central computer will be interrupted. To determine the failure or functionality of the Modem, follow the guided steps below.
NOTE: The tests are to be completed after verifying that the Central Communication Surge Board located near the central computer is functioning properly.
Operation of the RX/TX Lights:
When functioning properly, the RX light on the Modem should be blinking regularly as the Central Computer transmits to the satellites in the system and as the satellites transmit replies.
When functioning properly, the TX light should blink only when the satellite in which the Modem is installed transmits a reply to the Central Computer.
The delay between transmitted replies from the satellite is dependent upon the number of satellites in the system; more satellites means it takes a greater amount of time for the Central Computer to poll each satellite, resulting in a longer delay.
*Note: During a system download, it can be many minutes before a particular satellite is called by the Central Computer. Make sure a download is not in progress when testing the Modem.
Troubleshooting a communication failure can be a complex process. Refer to the flowchart below for guided steps.
1. Is the TX light on solid with no blinking? If so, skip to step 14.
2. Is the RX light on solid with no blinking? If not (RX light is off or is blinking), skip to step 6.
3. Unplug the 2-wire communication connector from the Modem.
4. Is the RX light still on solid ? If so, skip to step 14.
5. The Modem appears to be picking up noise or a signal from the 2-wire communication path when connected. A Modem in another satellite on the same communication path may be stuck in transmit.
Proceed to check communication wires along the path for bad connections and improper grounding of the communication cable’s shielding.
Once the source of the signal or noise is identified and eliminated, if the communication failure at this satellite location persists, begin at step 1 again.
6. Is the RX light blinking on and off? If not, skip to step 9.
7. Is the TX light blinking on and off? If so, skip to step 9.
8. Verify that the Timing Mechanism’s display shows the satellite’s proper CSG and SAT address settings. On an OEM Network 8000® Timing Mechanism, this can be found in the Config-Review menu.
9. Power off the satellite and remove the Modem. Inspect the Modem carefully for damage, including, but not limited to; corrosion, burn marks or signs of surge-related damage.
10. Inspect the fuses on the Modem as well as the fuse holders:
Each fuse should be tested with a multimeter on the Ohms setting. When testing the fuse, place the two probes of the multimeter on each end of the fuse. The multimeter should display a reading less than 1 Ohm.
Check the fuse clips for corrosion or oxidation.
Check to see that the fuse clips hold the fuses tightly.
Look for accidental contact between each fuse clip and the adjacent fuse clip or its installed fuse.
11. Verify that the 3-position 2-wire communication connector on the communication wires matches the connector on the Modem.
OEM Modems are equipped with either a grey 3-position 2-wire communication connector or a green or black 3-position 2-wire communication connector.
The grey 3-position 2-wire communication connector is not interchangeable with the green or black 3-position 2-wire communication connector.
Using the incorrect 2-wire communication connector will result in an unreliable connection or no connection at all.
Verify that the two communication wires are inserted into positions 1 and 2 on the 3-position connector. Confirm that the connections are solid and tight.
12. If the modem has no visible damage, and any issues with the fuses and/or 3-position communication connector have been resolved, reinstall the modem, power the satellite back on, and retest.
13. Verify that no other satellites in the system have been inadvertently changed to the same CSG and SAT address as the satellite location being tested.
It is not uncommon for the address DIP switches on an OEM Network 8000® Timing Mechanism to fail as they age, causing the address to change on its own. In some cases, this will cause the Timing Mechanism to have the same address as another satellite, causing a communications conflict as both satellites reply simultaneously to the Central Computer.
14. Power off the satellite and unplug all cables and connectors from the Modem.
Remove the Modem from the satellite and take it to a known-working satellite location to test.
*Note: Prior to installing the Modem at a known-working satellite location, be sure to power off the satellite at the known-working satellite location. Power to the satellite should always be off before installing or removing components.
Before installing the Modem in a known-working satellite location, verify that the 2-wire communication connector at the known-working satellite matches the 3-pin connector on the Modem. (See description in step 11.)
Power on the satellite.
If the known-working satellite location begins to experience a communication issue when the Modem is installed, the Modem is damaged and should be replaced.
Replacement Standard Modems can be purchased here.
*The SuperParts™ Standard Modem for Network 8000 is a direct-fit, fully compatible replacement for all generations and revisions of the OEM modem.
15. If the communication issue did not follow the Modem to the known-working satellite location, the Timing Mechanism at the original satellite location will need to be tested.
Start by powering off the satellite at the original satellite location.
Next, unplug all cables and connectors from the Timing Mechanism.
Using a Phillips screwdriver, unscrew the screws used to hold the Timing Mechanism in place.
Remove the Timing Mechanism and take it to a known-working satellite location to test.
*Note: Prior to installing the Timing Mechanism at a known-working satellite location, be sure to power off the satellite at the known-working satellite location. Power to the satellite should always be off before installing or removing components.
Install the Timing Mechanism at a known-working satellite location, making sure to connect all cables and connectors to the Timing Mechanism.
Power the satellite back on.
Set the CSG and SAT on the Timing Mechanism to the correct addresses for the satellite.
If the communication issue occurs at the known-working satellite location, the Timing Mechanism is damaged and should be replaced.
Replacement Timing Mechanisms can be purchased here.
16. If the communication issue did not follow the Timing Mechanism to the known-working satellite location, remove the Modem Cable from the original satellite location and visually inspect it for signs of corrosion or other damage.
If any corrosion or damage is seen, the Modem Cable should be replaced. If the Modem Cable appears to be in good condition, take it to a known-working satellite location to test.
*Note: Prior to installing the Modem Cable at a known-working satellite location, be sure to power off the satellite at the known-working satellite location. Power to the satellite should always be off before installing or removing components.
If the communication issue occurs at the known-working satellite location when the Modem Cable is installed, the Modem Cable is damaged and should be replaced.
Replacement Modem Cables can be purchased here.
Lesson tags: toro, modem, standard modem, network 8000, toro network 8000, network 8000 repair, network 8000 help, network 8000 troubleshooting, network 8000 exchange, network 8000 motherboard, network 8000 modem, boardtronics
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