Analysis: 1, communication chip (75 176) is bad.

2. The signal line is open.

Maintenance: 1. Check the signal wire of the window machine, and replace the signal wire if there is an open circuit.

2. If there is no problem with the signal line, replace the 75 176 chip.

Fault 2: The network connection is unstable. Communication detection has a flower screen (not connected with a fixed window machine). .

Analysis: 1. There may be something wrong with the communication chip of the network card.

2. Whether the signal line is grounded.

3. Whether there are three grounding wires in the system.

4. The 75 176 chip of a window machine is unstable.

Maintenance: 1. First, replace the communication chip 75 176 on the network card. If the phenomenon still exists, please follow the following steps to check.

2. Check whether the system (including power plug-in board and UPS input/output) has grounding wire, and remove the grounding wire.

3. Check the circuit to see if any signal wires are exposed to the ground or connected to metal.

4. If everything is normal, please check the communication several times to see if there is any abnormal connection of a single window machine, and replace the 75 176 chip of the abnormal window machine.

Fault 3: All window machines can't be connected.

Analysis: the network card 1, 75 176 chip is broken.

2. The main signal line of the network is open or short-circuited.

3. The window machine signal line is short-circuited.

4. A single window machine affects the whole communication.

Maintenance: 1. Replace the 75 176 chip of the network card.

2, a window machine connection, if it can be connected to and normal, add a window machine connection, constantly increase the window machine, see if there is any window machine that affects the whole network, if so, replace it with 75 176 or 89C52. Still no, change the motherboard.

3. If one can't be connected, check the main signal line to see if there is a short circuit or an open circuit.

Fault 4: No card reading.

Analysis: 1, there is something wrong with the communication line.

2. The card reader, IC card head or RF head is damaged.

3. The window machine program is damaged.

Maintenance: 1. Check the communication line for short circuit or open circuit. If disconnected or connected.

2. Replace the good reading and writing equipment (card reader, IC card head or RF head). If the card is read well, it means that the original reading and writing equipment is damaged. If it is a reader, replace the magnetic head. If it is an RF reader, replace the RF head. It is an IC card to replace the IC card head.

3. If you still don't read the card after replacing the reading and writing device, please replace the window machine program chip 89C52 or 27C64.

Fault 5: Card swiping crashes.

Analysis: 1. The motherboard voltage is insufficient or unstable.

2. The communication connection is not good.

Maintenance: 1. Check whether the voltage reaches 5.3V or whether the voltage value is stable. If there is any problem, please replace the power supply.

2. Check whether the communication connection is normal. If it is unstable, replace 75 176 or replace the signal line.