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Trouble-Shooting The Sheet Feeders Of The 8000

18 Jan, 2001 By: Steve Geishirt imageSource

Trouble-Shooting The Sheet Feeders Of The 8000

Trouble-shooting the Multi-bin Mailbox units or the Sheet Feeder units shouldn’t be that hard, but I find techs all the time who prefer to not deal with them if possible. What many of them do not know is that HP has given you some great tools on the 8000 versions of MBM (multi-bin mailbox) units and HCI (High Capacity Input) units.

In this article, I’d like to take a look at the different versions of these units, and explain how to run the tests on them, and what to expect so you know what is supposed to happen when you run these tests. Considering the amount of material for testing the HCI and MBM units, we will cover just the HCI units in this article and finish up next month by covering the MBM units.

Paper Handling Accessories Overview

Lets first start getting an overview of these paper-handling accessories. There are five variations of the MBM units for the 8000 lines of printers. The 8 bin unit, 5 bin with stapler, 7 bin tabletop, 3000 sheet stacker and 3000 sheet stacker with stapler.

The HCI units consist of the 2000 sheet feeder and a 2x500-sheet feeder. While the HCI units will work on the 8000 and 8100 without any problem, the 8500/8550 must be ordered with these units preinstalled, as they are not an individual option that can be added later. The 5Si optional accessories, by the way, have been discontinued but the 8000 options have been made to down grade to and replace those discontinued accessories; with some exceptions. The 2x500-sheet feeder, 7-bin mailbox and 3000 sheet stackers will not function on the 5Si printer. Note that the 5Si optional accessories should not be used on the 8000 versions of printers. To add to the confusion, the 3000 sheet stacker will only work on the 8100, 8150 and 8550 printers, but not the 8000 or 8500.

To better summarize things, listed below is a quick translation of accessories that are functional to each printer type.

The tests that can be run on each of these 8000 version of accessories test the mechanical functions and not the “c-link” connections. In other words, the cables linking the accessories are not tested. Remember that these tests can only be performed on the 8000 versions of accessories, the 5Si accessories do NOT include these tests.

Internal Test

Both the 2000 sheet and 2 x 500-sheet feeder for the 8000 versions of printers have internal tests. To set up the tests, remove the rear cover of the HCI unit, 4 screws. The rear cover can be removed with a printer on top of the HCI unit although this may make it more difficult to trouble-shoot should you want to remove other covers to view what is going on. Once the rear cover is removed, locate a set of four DIP switches on the controller PCA of the HCI unit). The settings of the DIP switches for each test is defined on the inside rear cover removed earlier. These settings can also be found in a perspective 8000, 8100, 8150 and 8500 version of service manual. The instructions will also list the set up procedures should a test require the drawer or VTU to be open so it can run properly. Last of all, there is an LED which is used to verify functionality of some tests and error codes. The error codes are registered in long and short bursts with the meaning of each sequence. The instructions for running each of the tests are listed on the inside of the rear cover, removed earlier (Figure 3), and in the service manuals. The tests include a motor test, stand along run test and sensor test.

Motor Test

The motor test runs all three motors in the HCI unit. It allows you to make an audio, and visual observation of these running motors. No error codes will be produced should one of them fail, so you may want to remove other covers to view the movement of all three motors. One door that’s designed to be removed for observation purposes is an access door located on the top of the unit, remove the two screws and the plate to get an eagle’s eye view. To run the motor test, the VTU (Vertical Transfer Unit) door must be open, or tilted out away from the unit, and the drawer(s) must be pulled out. If these procedures are not followed, the test will not run. The motor test is programmed into the controller PCA of the HCI unit via a set of DIP switches. The blue lever located below the controller PCA activates the test once the DIP switches are set. I strongly suggest you unplug the unit from the AC power outlet when the tests are not running or another test is being set up. Also, be careful when running the test with the power on and the covers off. This test will not pickup paper when it runs as it is meant to allow you to view and listen to the turning of the motors and gears.

Stand Alone Test

The next test, stand alone run test, feeds paper through the paper path of the HCI unit. The VTU must be in the upright position for this test to work as well as the drawer must be closed with paper in it. When testing the 2 x 500 sheet unit, one tray can be tested by opening the paper tray you don’t want to test. Leaving them both in defaults to one of the two, the one that lifts to proper paper height first, and then moves to the other once the paper has run out of the first tray. If a paper drawer is not closed, or the VTU is not placed in the up position, an error code will occur. The error is denoted by the flashing LED on the controller PCA. The combination of bursts and their meaning can be found on the inside back panel of the HCI unit, or in the service manual. A couple of quirks were identified on our 2000 sheet feeder while running this test. The 2000 sheet feeder had a lifter malfunction raising the tray only part way thus producing an error. The LED flashing code was 3 long and 1 short. Resetting the test, sometimes twice, the tray would lift all the way to the top to eliminate this error. If the test is working properly, unlike our 2000 sheet feeder, you should get long steady bursts from the LED on the controller PCA. When the test is running, paper is picked up from the tray and fed up through the VTU. If there is a printer on top of the HCI, paper will bunch up and jam as it feeds into the printer as this test only functions on the HCI and not the printer itself. The sensors will not cause a paper jam as this test is designed to allow you to view the functionality of paper pickup and movement through the HCI unit. Note that tilting the VTU out or opening the drawer will stop the test and force you to reset the unit before starting again.

The Sensor Test

The sensor test allows you to test the multiple sensors of the sheet feeder. To run this test, you must pull out the drawer(s) and open the VTU door; this will open all the sensors for testing. When you toggle or close a sensor the LED on the controller PCA will light up indicating the sensor is working. Closing either the drawer or the VTU door will activate a sensor causing the LED to turn on and stay on while it stays closed. Thus, if you wish to check a sensor while another sensor is activated, the LED will not change. I find this test to work best with the access panel removed so you can toggle all the different sensors. Figure 5 shows the 2000 sheet feeder and the quick locations of the different sensors in the 2000 sheet feeder. Figure 6 points out the function of the two sensors near the feed/separation rollers.

Perhaps most of the service techs who don’t want to work on these units swore off the HCI units in the 5Si days when it was more difficult to trouble-shoot. With the improved trouble-shooting tools, easy instructions and error codes HP has provided, that fear should subside. No more trying to rig the sheet feeder and hope everything works right so you can watch what’s going instead of wondering what you’re seeing is due to not rigging the test the right way. Next month we'll take a look at the tests on the MBM units.

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