Error has occurred.

Oh boy,
the last time this happened to me, I lost a rather good HP printer.
I was not able to save it due to the ink drying on important componets.
Sorry I have no constructive info for you, but I do wish you luck.

the printer has occurred. error code 006.

To check the light Pattern of your printer

Click on Light and Error HP Laser jet 1012 Printer

Check the error details from the above link

Condition of the printer Action/Description Ready

The printer is ready to print. No action is necessary. Processing

The printer is receiving or processing data. Wait for the job to print. Processing...(job name) Ready LED is blinking.

This message is displayed while the printer is processing a current job, but has not begun to pick pages. Processing...(job name) From Tray XX Ready LED is blinking.

This message comes up for any job, once the printer starts to pick paper. Manual Feed or Continuable Error

The printer is attempting to Manual feed, media is not loaded in the paper tray, media loaded is the wrong size or type. Verify that the correct media is loaded.

Press and release the GO button to continue printing. Out of memory

The printer is out of memory. The page you are printing might be too complex for the printers memory capacity. Try lowering the resolution. See Understanding print quality settings for more information. Door open, media out, no print cartridge, or media jam

The printer is in an error state that requires operator intervention or help. Check the following:

• The print cartridge door is completely closed.
• Media is loaded.
• The print cartridge is correctly installed in the printer.
• There is no media jam.

Printer initialization

A printer initialization is taking place. No action is necessary. Fatal error

All lights are on.

• Unplug the printer for 30 minutes, and then plug it back in.
• If the printer still has an error, contact HP Support.

All lights are off.

• Verify that the printer is turned on.
• Make sure that there is power.
• Unplug both ends of the power cord, and plug them back in.

Job Cancel

All the LEDs cycle. Canceling...(job name)

The Job Cancel button was pressed and the job is aborted. Power ON

All the LEDs cycle. Checking Paper Path and Checking Printer

This only occurs at power up. Cleaning mode/Engine test

A cleaning page or engine test page is printing.

All the LEDs cycle. Cleaning Page prints

Wait until the cleaning page is finished printing and the printer is in Ready mode. This could take up to two minutes.

Wait until the engine test page is finished printing and the printer is in Ready mode. Clearing Event Log

All the LEDs cycle.

This will happen automatically during an NVRAM Init and a cold reset. No message will be displayed. No Action is Necessary. Power On

Initializing

This occurs when the product is powered on and coming out of EDOS. No Action is Necessary.

You need to count the number of flashes, usually long green then a certain number of flashes, sometimes alternating red and green flashes. I need to know the number of flashes to tell you what the error is.

Maybe the toner is low... According to the manual, a blinking red light:

• A minor error is occurring and
the printer is waiting for the error
to be cleared. When the problem
is cleared, the printer resumes
printing.
• The toner cartridge is low. Order
a new toner cartridge. You can
temporarily improve print quality
by redistributing the toner. See
page 8.3.
• The toner is totally exhausted.
Remove the old toner cartridge
and install a new one. See page
8.4.
• The toner cartridge reached the
end of its life.

From the service manual:

Troubleshooting Procedure Table
Step Actions and Questions Yes No
1 Check the Laser Unit for correct
installation.
Is the Laser Unit correctly installed?
Go to step 3. Reinstall the
Laser Unit. Go
to step 2.
2 Cycle the power.
Does the error still occur?
Go to step 3. Complete.
3 Check the wiring harness connectors
P/J40, P/J41, P/J411, and P/J412
between the MCU Board and the Laser
Unit.
Are the connectors securely
connected?
Go to step 5 Reconnect the
connectors. Go
to step 4.
4 Cycle the power.
Does the error still occur?
Go to step 5. Complete.
5 Replace the Laser Unit (page 8-31).
Does the error still occur?
Replace the
MCU Board
(page 8-59).
Complete.

The online/error light is always red, and I can't print. I turn the printer off, change the toner and the light is still red, what can I do

Check your manual, there is a solution there or download the user guide from
this site below or read the information below.

http://downloadcenter.samsung.com/content/UM/200602/20060216163720484_ML-2010_English.pdf


LED pattern Possible Problems and Solutions
Your system has some problems. If this problem occurs,
contact your service representative.
On Line/Error LED
lights red
• Paper jam occurs. To solve the problem, see “Clearing
Paper Jams” on page 5.6.
• The front cover is open. Close the front cover.
• Paper tray is empty. Load the paper in the Tray.
• The toner cartridge is out of toner. Remove the old toner
cartridge and install a new one. See “Installing the Toner
Cartridge” on page 2.4.
• You pressed the Cancel button while the printer is
receiving data.
• In Manual Feed mode, there is no paper in the manual
tray. Load paper into the manual tray.
• If the printer is receiving data, the On Line/Error LED
slowly blinks green.
• If the printer is printing the received data, the On Line/
Error LED blinks green fast.

LED pattern Possible Problems and Solutions
Your system has some problems. If this problem occurs,
contact your service representative.
On Line/Error LED
lights red
• Paper jam occurs. To solve the problem, see “Clearing
Paper Jams” on page 5.6.
• The front cover is open. Close the front cover.
• Paper tray is empty. Load the paper in the Tray.
• The toner cartridge is out of toner. Remove the old toner
cartridge and install a new one. See “Installing the Toner
Cartridge” on page 2.4.
• You pressed the Cancel button while the printer is
receiving data.
• In Manual Feed mode, there is no paper in the manual
tray. Load paper into the manual tray.
• If the printer is receiving data, the On Line/Error LED
slowly blinks green.
• If the printer is printing the received data, the On Line/
Error LED blinks green fast.

The red light, along with the paper light being lit indicates that it is having a problem feeding the paper OR it is set wrong for duplexing. Check your manual on page 3-4 or download a manual at:
http://www.brother-usa.com/ModelDocuments/Consumer/Users%20Manual/UM_HL_5140_5150D_5150DLT_5170DN_5170DNLT_EN_1295.PDF

I can't tell which of the error conditions fits your situation, but this should put you on the correct path to figure it out.