Set your multi-meter at a scale to handle at least 40 VDC. Touch or attach your ground probe to the Control Unit divider panel. With your other probe, touch (in succession) each test point and either end of the fuses at which you are measuring. With motors connected, voltages should be as follows:

• S 100 Power Supply fuses
  F1 - +18 to +20 V
  F2 - -9.5 to -11 V
  F3 - +9.5 to +11 V
  
  J1 Connector
  
  All red wires out +11 V
  Yellow wire +20 V
  Grey wire -11 V
  Blue wire - GND
  
  Off S 100 transformer (On A/C scale)
  
  Terminal 1 to 2 - +120V
  Terminal 3 to 6 - 25V
     

• FOR OLD STYLE STEP/DRIVE BOARD
  
  Big Blue Capacitor
  From screw to screw 32 Volts. If no voltage or low, bridge rectifier or no AC voltage.
  
  Transformer (set meter to 200 ACV scale)
  Pole 1 - Approx. 115 V + 2
  Pole 2 - Approx. 1.2 V + 2
  Pole 3 - Approx. 13 V + 2
  Pole 4 & 5 - Approx. 2 V + 2
  Pole 6 - Approx. 13 V + 2
  
  Old Style Brown Stepper Board Fuses
  
  F1- 5 AMP, 250 Volt
  F2- 5 AMP, 250 Volt
  F3- 5 AMP, 250 Volt
  F4- 5 AMP, 250 Volt
  F5- 1 AMP, 250 Volt
  

Resistor Bank Check (Control units with Brown Stepper Boards)

Disconnect each of the 4 wires from step/drive board to resistors.

Hold a probe from your ohmmeter to an exposed section of the wire that shorts all 4 resistors together across the bottom of the bank. Insert the other Probe into the connector of each resistor in succession

On a 5 ohm resistor bank (for 4.6 amp motors), each resistor should measure 4.5 to 6 ohm’s individually (not less than 4.2).

On a 10 ohm resistor bank (for 2.9 amp motors), you should measure 9 to 11 ohm’s individually (always over 9).
    NEW STYLE STEP/DRIVE BOARD (Blue)

With only 1 blue capacitor

P3 on Blue Stepper Board to (-) on blue capacitor, 20Volts   

Drawings actual say that 24 volts is needed for input. Original brown stepper board had 25 volts for  cutter switch. Air solenoid is 24 volts. Blue stepper board gets less than 20, thus 24 volt requirement is marginal. More fonts/board means less voltage for cutter down.

25 VDC Cap (+) side to (-) side - 15v to 17 volts

Fl & F2 Fuses on stepper board to (-) side of blue capacitor- 15v to 17v

P2 Connector to (-) side of blue capacitor - 15v to 17v

P3 Connector to (-) side of blue capacitor - 18-20 v

50 V capacitor (Dual blue capacitors with capacitor Connector Board board on top of 2 blue capacitors)

+27 V to +32 V across capacitor

Fuses - Fl & F3 - Approx. 4.5V

F2, F3 & F5 - Approx. 27 to 30V

Blue Stepper Board Fuses

F1 & F2 - 12 amp, 250 Volt Fast

S-100 P/S Fuses    Fuse F1- Slow Blow, 5Amp, 250 V

Fuse F2 - Fast Acting Fuse, 3 AMP, 250 v

Fuse F3 - Fast Acting Fuses, 10 AMP, 125 V

BRIDGE RECTIFIER
For this test you will need a multi-meter with a diode checker. Touch each multi-meter lead to adjacent terminals. If you get a measurement/bee, the diode between the tested terminals is good. If you do not get a beep, swap the multi-meter leads on the same set of terminals. If you do not get a beep after you swap, the bridge rectifier is bad. You will need to test each adjacent set of terminals.



                                                         
  

LOCATION OF FUSES SYSTEM ONE

Rear Panel - Auxiliary 5amp, Stepper 20amp, Main 10amp

S-100 Power Supply - F1 5amp, F2 5amp, F3 10amp

Stepper Driver Board - F1, F2, F3, and F4 6amp, F5 1 amp

MISCELLANEOUS - Fuses

Always use a voltage meter to check the continuity of fuses. Visual checks can be misleading
Generally when having a problem on a board which has a fuse, remove the fuse and check the receptacle for corrosion. After cleaning, mash the two wire retainers which hold each end of the fuse in place. Sometimes a loose fuse will cause a loss of power

Using The Right Fuse For The Right Job

Use Fast Acting fuses on power supplies. Use Slow Blow fuses where motors are involved. Slow Blow’s won’t blow with normal inductive motor surge, while Fast Acting will. Both will blow with an overload.

Additional Checks

Check all wiring on the left hand side of the control unit for loose connections or bad crimping on connectors. A slight tug on each wire at the connector will verify that the wire is firmly crimped, and that the connector is firmly attached. Immediately replace any burned or melted siring, taking note of the component the wiring is attached to. If there is still a problem after the preliminary check, it could be this component that is causing the problem.

Verify that all fuses are good, of the correct amperage, and snap firmly into place. If the fuse appears loose, remove the fuse and squeeze both sides of the fuse holder together, so that the fuse will make better contact