Trouble Shooting (Part 2)

Question 1

What is burn in? What kind of modern monitors are susceptible to it?

Answer 1

If you leave the same image up for too long (hours), a static image can be permanently burned into the screen.

This only happens to plasma screens

Question 2

What is image persistence? How do you fix it?

Answer 2

This is the LCD monitor version of burn in. The difference is that the effect is not permanent on LCD screens.

It can be fixed by exercising the pixels. There are tools that can help you do this. You can also just use a white screen screensaver for several hours.

Question 3

You have no network connectivity. Why?

Answer 3

1. They aren’t connected to the WLAN. (Maybe network connectivity is switched off or maybe the computer just forgot about the WLAN)
2. The Ethernet cable is disconnected or damaged.

Question 4

What can cause a computer to have a Link local address/APIPA?

Answer 4

These are generated automatically by the network card if it is not assigned one. This allows them to connect to the subnet, but it cannot go beyond that. Reasons for this happening are:
- Can’t connect to the DHCP server. (check to make sure the server is online. Also, sometimes a router will prevent it from getting from another subnet to your subnet)

(Questions for further investigation: How do you know that a computer has generated a link local address? What is a DHCP server?)

Question 5

What could cause a computer to have limited connectivity? (It can connect to the network, but can only access websites by entering their IP address. Not the website name.)

Answer 5

1. The DNS server is offline or unreachable.
2. Use ipconfig and nslookup in PowerShell to investigate the problem

(Ask dad about this entire question)

Question 6

A user only has local connectivity (can’t get out of their subnet). Why?

Answer 6

1. The router is offline.

2. If the computer has assigned itself an APIPA/Link local address, check the DHCP server.

Question 7

What could cause intermittent connectivity?

Answer 7

1. Low Wi-Fi signal

2. Defective Ethernet cable/port

Question 8

What is going on when you get a message saying “IP address conflict” or that another computer is using your IP address? (Another key symptom is that you will have no network connectivity)

Answer 8

• Duplicate IP address. (find the IP address that is in conflict. Figure out which other computer also has that address)

Question 9

What can cause slow transfer speeds?

Answer 9

1. The WLAN has been configured to run at a lower speed than it should be.
2. Half Duplex-Ethernet

Question 10

What can cause a computer to have a low RF signal?

Answer 10

(This will cause intermittent connectivity)

1. The computer has a bad Wi-Fi signal (get another access point)

(Ask dad)

Question 11

What does SSID stand for?

Answer 11

Server Side Identifier

Question 12

SSID not found. Why?

Answer 12

1. SSID broadcast is disabled
2. The radio on the device is disabled

(Ask dad)

Question 13

What’s the difference between half duplex and full duplex?

Answer 13

Half-Duplex:
- Can send or receive, but not both (like a walk-talkie)
Full Duplex:
- Can send and receive simultaneously (like a phone)

Question 14

How can you change between full duplex and half duplex?

Answer 14

Look at both sides of the connection. For the computer, you need to go to the diver settings of the network card. For the Switch, log in via a web management tool and set the port to the appropriate setting. (make sure the computer is compatible with the switch setting)

(How do I get to driver settings?)