DoorKing 1812 Classic - Manual (Page 40)

1812-065-U-12-13 38
If noise or hum is present on the homeowner's phone line after installation of the 1812 telephone intercom system, use the
procedure on the next page to find and correct the source of the noise. This procedure will require the use of a telephone test
set (DoorKing P/N 1800-050 or equivalent). Typically, noise is usually introduced into the system because of incorrect wiring,
poor quality of wire, wire runs exceeding maximum distances, phone and high voltage power wires running in the same conduit
or in very close proximity to each other, a wrong type transformer was substituted, or the phone lines, power lines or 1812
circuit board is grounded.
1. Place the BYPASS switch in the BYPASS mode (slide switch to right). If noise goes away, problem is with phone in/out
wiring, power wiring, or 1812 unit. Place the BYPASS switch in the ENTRY SYSTEM mode (slide switch to left) and proceed
to step 3. If noise is still present when switch is in the bypass mode, disconnect C.O. wires and HOUSE wires from bypass
switch. Connect the C.O. wires to the HOUSE wires. If the noise goes away, the bypass switch is bad and needs to be
replaced. If noise is still present, contact the telephone company for service.
2. Remove all external items connected to the 1812 unit, such as back-up batteries, relay connections, push button
switches, or time clocks. All terminals should be free of any wiring except terminals 1 and 2 (PHONE IN WIRES), terminal 3
(CASE GROUND WIRE), terminals 4 and 5 (PHONE OUT WIRES), and terminals 17 and 18 (16.5 VAC POWER WIRES). If
noise is still present, proceed to step 3. If noise is gone, the source of the noise is one of the external devices that were
connected to the 1812. Reconnect them one at a time until you find the item that is the source of the noise.
3. Remove the PHONE OUT wires from terminals 4 and 5 at the 1812 unit. Connect your handy phone directly to the loose
PHONE OUT wires. The wires should be dead and you should not have any dial tone on these wires. If you do have dial
tone, the 1812 is wired incorrectly. Disconnect power immediately and refer to the wiring information section in this
manual.
4. Disconnect your handy phone from the PHONE OUT wires (step 3). Remove the PHONE IN wires from terminals 1 and 2
at the 1812 unit. Connect the PHONE IN wires to the PHONE OUT wires. This completely disconnects the 1812 unit from
the circuit. Check the phones in the house. If the noise is gone, problem is with or in the 1812 unit, or with the power
supply or power wiring. Reconnect the PHONE IN wires to terminals 1 and 2, and the PHONE OUT wires to terminals 4 and
5, then proceed to step 5. If the noise is still present, problem is with the PHONE IN or PHONE OUT wires running from the
1812 unit to the bypass switch. These wires will need to be replaced and/or re-routed to correct the problem.
5. Disconnect the 24 VAC wires from terminals 17 and 18. If the phone line is now clear, the problem is in the 24 VAC
power run. Check the power lines for a ground, or running next to high voltage wires, or an improper wire size and insula-
tion, or too long of a wire run. If noise is still present, go to step 6.
6. If noise is still present at this step in the trouble shooting sequence, this would indicate a short to ground internally in
the 1812 unit. Remove CN2 8-pin door accessories plug from the circuit board, and check for noise again. If noise is gone,
this would indicate a problem with the microphone board, speaker, push button, or lights on the front panel assembly.
Check for any shorts to ground on any of these components or wiring. Check to be sure that none of the wires are pinched.
If noise is still present, check the wires entering the back of the 1812 box and be sure that none are pinched. Be sure that
these wires are not touching the back of the 1812 circuit board, possibly causing a short to ground. If all of the above steps
fail to identify the source of noise, contact DoorKing for additional assistance.
5.4 Isolating Noise Problems
5.5 Troubleshooting Table
Symptom Possible Solution(s)
Cannot get into
programming mode. • Wrong master code entered. Start over.
• Waiting too long between pushing buttons. Enter information quicker.
• Keypad is not plugged into board correctly. Cable points down (Red wire on the left at circuit board).
• Waiting too long between pushing buttons.
• Forgetting to press * first when programming.
• No power. Check for 24 VAC input power.
• Check that the keypad is properly connected to the circuit board. The cable on the plug points down
when connected to the circuit board.
• The system is not wired in series with the resident phone line. Check the PHONE IN terminals (1 & 2)
and the PHONE OUT terminals (4 & 5).
Keypad is dead.
System emits a long tone
and cancels programming.
Dial tone is heard on the
1812 speaker.