This section will help to isolate possible power problems in the DLC. It will not isolate any problems to any specific electronic components on the DLC card, but will help isolate fuse or battery pack or battery cell problems.

If you report power problems to CROPSCAN, Inc., please provide the voltage readings from each of steps 3, 5, 8, 9, 10, 11, and 12 below.

Equipment required: small phillips screwdriver and a voltmeter with a DC scale to about 20 volts.

The following steps assume that battery cells are installed in the battery pack as pictured below.

• Step 1) Loosen and remove the two screws on each side of the DLC front panel.

• Step 2) Slide the front panel forward and remove the attached DLC card from from the case:

  DO NOT press the hard reset button (red switch with black button in upper left-hand corner of DLC card as pictured below.)

  Step 3) Remove each battery cell and measure the voltage across each and check the condition of the battery cell holder connectors.

  A fully charged cell will measure about 1.2 to 1.4 volts. Cells which measure from 1.1 volts to 1.2 volts are in their useful operating range. Cells that measure less than 1.1 volts are discharged and should be recharged. If they measure less than 0.6 volts then they should be charged in an external charger or replaced with a new cell, because if they all get below 0.5 volts, the in-rush current needed to charge them will cause fuse FS1 to blow. If they measure close to zero volts, after having been charged then it is likely the cell has been short-circuit damaged from over-discharge and should be replaced.

  While the battery cells are removed, check the battery cell holder contacts for any signs of corrosion and clean them if any corrosion is found.

  Corroded contacts shown on the left. Clean contacts shown on the right.

  Corrosion can occur if the batteries (NiCad or Alkaline, in particular) are left to fully discharge in the DLC, due to any leaked chemicals from the batteries coming in contact with the metal connectors.

  It is recommended to recharge the batteries in the DLC overnight before each use and recharge them at least once per month or two, when not in use or simply remove them for longer term storage.

  NOTE: If you need to use Alkaline type batteries, say in the situation where you are out in the field and the rechargeable batteries have run down, DO NOT connect the A/C adapter to the DLC while the Alkaline batteries are installed. Any charging will cause Alkaline to be discharged from the battery cells and will cause corrosion to the battery cell holders and can etch away printed circuit trace connections on the DLC card itself.

• Step 4) If the cells measure 0.6 volts or more then replace them into the battery pack cell holders. Replace any empty cell positions with known good battery cells.

• Step 5) Check the A/C adapter output by connecting the A/C adapter to a wall outlet and measure the voltage at the plug as shown below (voltmeter red lead to center of plug and black lead to outside of plug):

  The voltage should measure around 17 volts.

• Step 6) Connect the voltmeter ground clip lead (black) to the top lead on switch SW2 (upper left-hand area in above picture, shown close-up below):

  This will be the reference point for all other measurements.

• Step 7) Connect the A/C adapter plug to the Power input jack on the DLC front panel.

• Step 8) Using the voltmeter positive probe (red), probe the far end of fuse FS1, located between the DLC front panel and the battery pack, as shown below:

  This point should measure about 15 volts with all batteries installed and about 16 to 17 volts without at least one battery, if the A/C adapter is properly plugged into the DLC and to an active A/C power source. If it measures higher, then fuse FS1 is likely blown. If this point measures close to zero volts then the DLC is not getting power from the A/C adapter. If this point measures more than about 9 volts then continue with the next step.

• Step 9) Now probe the closer end of fuse FS1, as shown below:

  NOTE: Also, check to see if either end of the fuse is loose. If a fuse had been replaced, it may be possible that the fuse clips may have become sprung enough that one of the ends of the fuse may not be held tightly. A symptom of this can be intermittent power-offs. It one end or the other is loose, remove the fuse and then squeeze the fuse clips together. Carefully replace the fuse and verify that it is being held tightly.

  This point should measure about 20 millivolts (0.02 volts) less the other end of the fuse if the fuse is good (not blown) and if the DLC is getting good power from the A/C adapter. If it measures less than 0.5 volts and the DLC is getting good power from the A/C adapter then fuse FS1 is indeed blown. Replace it with a new fuse.

  A good fuse has a little silver looking wire through it, as shown below. A blown fuse will have a break in the wire.

• Step 10) Probe the battery pack connector (rightmost of the three) corresponding to the red wire, as shown below:

  With the A/C adapter connected to the DLC, this point should measure a little over 11 volts.

  Remove the A/C adapter from the DLC and re-measure the same point as above. With good batteries installed, this point should measure somewhere between 8.8 and 11.0 volts depending on the charge condition of the battery cells. If so, reconnect the A/C adapter to the DLC and continue with the next step below.

  If it measures low (less than 2 volts) then there is a connection problem in the battery pack and most likely a corroded battery cell connector. Remove the battery cells, re-check the battery cell holder connectors, and re-clean as necessary as described above. If that still does not solve the connection problem then contact CROPSCAN, Inc. to discuss obtaining a replacement battery cell holder pack.

• Step 11) If your DLC does not have fuse FS2 (Model 92 DLCs) then skip this step and go to the next step, otherwise probe each end of fuse FS2, shown below:

  NOTE: Also, check to see if either end of the fuse is loose. If a fuse had been replaced, it may be possible that the fuse clips may have become sprung enough that one of the ends of the fuse may not be held tightly. A symptom of this can be intermittent power-offs. It one end or the other is loose, remove the fuse and then squeeze the fuse clips together. Carefully replace the fuse and verify that it is being held tightly.

  If both ends of the fuse measure very close to each other then fuse FS2 is good. If the fuse is blown then they will differ in readings by at least 1.5 volts. Replace the fuse if it is blown.

• Step 12) Probe D48 and D49, as shown below. D48 and D49 are connected together on the card, so you may probe either one.

  This point should measure between about 5.7 to 5.9 volts, if fuse FS1 is good (not blown), indicating that the DLC internal voltage regulator circuit is functioning correctly. If this voltage is much lower or much higher then contact CROPSCAN, Inc. to discuss return of the DLC for repair. If your system was purchased through a CROPSCAN, Inc. Reseller, then the return and a possible loaner will have to be arranged through them.

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