The monitor appears to be working but will not receive an image from a Mac server machine. I have had this monitor on the machine for a number of yrs and it worked fine. I tried a different monitor (ACER) and got the same result. The mouse cursor shows up on the screen but the computer image does not

Sounds like your screen went bad.
Close the lid, attach an external monitor, open lid and see if the screen appears on the monitor.

Resetting the PRAM may do the trick also:
You reset the PRAM by rebooting a Mac and then immediately hold down the Command+Option+P+R keys, you will then hear the Mac reboot sound again, signifying your PRAM has been reset. You must hit the key combination before the grey screen appears otherwise it won't work.

Happy New Year,
Kerry

Hello Saul Takahashi it may need some technical skills, so please if you can just call my toll-free number +1 (833) 493-0111.

Cheers
John

Problem Cause Solution Colored lines appear. The exposure glass or scanning glass is dirty. Clean them. See "Maintaining Your Machine", About this Machine . Copies appear dirty. Image density is too high. Adjust the image density settings. See "Adjusting Copy Image Density", Copy and Document Server Reference . Copies appear dirty. Auto Image Density is not selected. On the control panel, select [Auto Density]. The reverse side of an original image is copied. Image density is too high. Adjust the image density settings. See "Adjusting Copy Image Density", Copy and Document Server Reference . The reverse side of an original image is copied. Auto Image Density is not selected. On the control panel, select [Auto Density]. A shadow appears on copies if you use pasted originals. Image density is too high.

• Adjust the image density settings. See "Adjusting Copy Image Density", Copy and Document Server Reference .
• Change the orientation of the original.
• Put mending tape on the pasted part.

The same copy area is dirty whenever making copies. The exposure glass, scanning glass, or ADF is dirty. Clean them. See "Maintaining Your Machine", About This Machine . The same copy area is dirty whenever making copies.

• The original that has already been printed is scanned.
• Original Type is set to [Text / Photo], and an original with text and photographs that can hardly be distinguished from each other is loaded.

On the control panel, press [Generation Copy], and then begin copying. Copies are too light. Image density is too light. Adjust the image density settings. See "Adjusting Copy Image Density", Copy and Document Server Reference . Copies are too light. A light copy may result when you use damp or rough grain paper. Use recommended paper only and be sure its storage environment meets the recommended temperature and humidity conditions. For details about recommended paper and the proper way to store it, see "Recommended Paper Sizes and Types" and "Paper Storage", About This Machine . Parts of images are not copied. The original is not set correctly. Set originals correctly. See "Placing Originals", Copy and Document Server Reference . Parts of images are not copied. The correct paper size is not selected. Select the proper paper size. Parts of images are not copied. Even if you place originals in the ADF correctly, margin of a few millimeters on all four sides of the original might not be copied. Use "Create Margin" function to reduce the image of its original size.
For details about missing image area, see "Missing Image Area", Copy and Document Server Reference . images appear only partially. The paper is damp. Use paper that has been stored in the recommended temperature and humidity condition. For details about the proper way to store it, see "Paper Storage", About This Machine . Black lines appear. The exposure glass or scanning glass is dirty. Clean them. See "Maintaining Your Machine", About This Machine . White lines appear. The exposure glass or scanning glass is dirty. Clean them. See "Maintaining Your Machine", About This Machine . White lines appear. The dustproof glass is dirty. Clean the dustproof glass. See "Cleaning the Dustproof Glass", About This Machine . Copies are blank. The original is not set correctly. When using the exposure glass, face the originals down. When using the ADF, face them up. A moir? pattern is produced on copies. Your original has a dot pattern image or many lines. Place the original on the exposure glass at a slight angle. Black spots appear on the copy of a photographic print. Because of high humidity, the photographic print has stuck to the exposure glass. Place the print on the exposure glass in either of the following ways:

• Place an OHP transparency on the exposure glass, and then place the print on the OHP transparency.
• Place the print on the exposure glass, and then place two or three sheets of white paper on it. Leave the ADF open when copying.

White stripes appear on the OHP. Fragments of paper are stuck to the OHP. Use a dry cloth to wipe any paper fragments off the back of the OHP. The image on the back side of duplex copies has mottled blank patches or is smudged. Missing patches and smudges are caused by moisture leaking from the paper.

• Do not install the machine in areas that are susceptible to low temperatures.
• Use paper that has been stored where temperature and humidity conditions meet the limitations we recommend. For details about the paper storage conditions we recommend, see "Paper Storage", About This Machine .
• Install the Optional anti-humidity heater. For details about the anti-humidity heater, contact your service representative.

When You Cannot Make Clear Copies

Check to see if there were any changes to the POP3 info and update your email accounts on each computer. The fact that the SMTP is working indicates the exchange server is working and the email addresses are vaild

The user manual that came with the printer should explain how to do this.

See extract below
Scan an image
You can start a scan from your computer or from the HP All-in-One. This section
explains how to scan from the control panel of the HP All-in-One only.
To use the scan features, the HP All-in-One and computer must be connected and
turned on. The HP Photosmart Software (Windows) or HP Photosmart Mac Software
(Mac) must also be installed and running on your computer prior to scanning.
● On a Windows computer, look for the HP Digital Imaging Monitor icon in the
Windows system tray (at the lower right side of the screen, near the time) to verify
the software is running.
Note Closing the HP Digital Imaging Monitor icon in the Windows
system tray can cause the HP All-in-One to lose some of its scan
functionality. If this happens, you can restore full functionality by restarting
your computer or by starting the HP Photosmart Software.
● On a Mac, the software is always running.
Tip You can use the HP Photosmart Software (Windows) or HP Photosmart
Mac Software (Mac) to scan images, including panorama images. Using this
software, you can also edit, print, and even share your scanned images. For
more information, see the onscreen Help that came with the HP All-in-One.
To scan to a computer
1. Load your original print side down in the right front corner of the glass.
2. Press Start Scan.
3. Press OK to select the default application to receive the scan, or press to
select a different application, and then press OK.
A preview image of the scan appears on your computer, where you can edit it.
4. Make any edits to the preview image, and then click Accept when you are
finished.

I suppose you should have some software running on your system to accept the file.

Check the user guide.

Scan an image
You can start a scan from your computer or from the HP All-in-One. This section
explains how to scan from the control panel of the HP All-in-One only.
To use the scan features, the HP All-in-One and computer must be connected and
turned on. The HP Photosmart Software (Windows) or HP Photosmart Mac Software
(Mac) must also be installed and running on your computer prior to scanning.
● On a Windows computer, look for the HP Digital Imaging Monitor icon in the
Windows system tray (at the lower right side of the screen, near the time) to verify
the software is running.
HP All-in-One overview
Note Closing the HP Digital Imaging Monitor icon in the Windows
system tray can cause the HP All-in-One to lose some of its scan
functionality. If this happens, you can restore full functionality by restarting
your computer or by starting the HP Photosmart Software.
● On a Mac, the software is always running.
Tip You can use the HP Photosmart Software (Windows) or HP Photosmart
Mac Software (Mac) to scan images, including panorama images. Using this
software, you can also edit, print, and even share your scanned images. For
more information, see the onscreen Help that came with the HP All-in-One.
To scan to a computer
1. Place your original print side down on the left front corner of the glass.
2. Press Start Scan/Reprints.
A preview image of the scan appears on your computer, where you can edit it.
3. Make any edits to the preview image, and then click Accept when you are
finished.

use pagemaker for scan your document.

Hold down the Command, Control, and Option keys while pressing 8.

I had a similar problem with a Mac Mini.  The problem was caused by a mix-matched resolution (the Mac tries to use 75Hz refresh rate, TV expects 60Hz).  The best solution I found was to remote into the Mac (I used LogMeIn.com) and change the resolution on the Mac from a remote computer until the image appears on screen.
Process: 1) Connect Mac to a normal monitor and install the LogMeIn server (or other VNC type application) 2) Connect the Mac to the TV 3) Connect to LogMeIn from another computer (preferrably one where you can see the TV) 4) Go to Applications / System Preferences / Display 5) Change the resolution to your TVs native resolution, and change the refresh rate to 60Hz

lb 20u does not support mac os,yet try the auto setup on the remote , if u are getting the image properly