HP color laserjet 2550 series Manuale Di Servizio

An engine test can help to identify printing problems, and a paper-path check can help to
identify problems in the paper path.

The engine test is used to verify that the print engine is functioning correctly. The formatter is
bypassed during an engine test, so the engine test is useful for isolating printer problems.
Because the engine test prints horizontal lines along the entire printable area of a page, it is
also useful for checking and adjusting registration.

The type of engine test and the input tray depend on the last print job. During the engine
test, the printer pulls media from the input tray that was used for the last print job. The last
print job also defines the type of engine test. If the last print job was a color print job, then a
color engine test is performed. If the last print job was a black-only print job, then a black-
only engine test is performed.

The engine test switch is inside tray 1, on the left side, just below the front cover.

To print an engine test:

1. Turn off the printer.

2. Turn on the printer.

3. Open tray 1 and load paper.

4. Press the engine-test switch (shown below).

The formatter must be connected to the ECU to perform an engine test. Otherwise, the
printer does not print the engine test.

1. Turn the printer off.

2. Press and hold   (Go).

Chapter 6 Troubleshooting

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