CHAPTER 1 AC/DC POWER DISTRIBUTION

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1 CHAPTER AC/DC POWER DISTRIBUTION AC THEORY OF OPERATION! DANGEROUS HIGH VOLTAGES ARE PRESENT IN THIS EQUIPMENT Always use the "One Hand Rule" when working with AC voltages by keeping one hand in your pocket or behind your back. Before removing wires from the ECO, always verify that the Tester is "OFF". Turn off the Main Power Switch on the front and unplug the AC power cord from the AC outlet. Start capacitor (Black) on compressor retains high voltage even when unit is off. AC DISTRIBUTION (Refer to FIGURE - Page - POWER DISTRIBUTION) The primary voltage applies V, 0Hz AC to the ECO Xtreme via the hot side (Black Wire) of the AC power cable. When the AC Plug is connected to a V power source, (Hot & Neutral) are routed to the ON/OFF switch. From the switch it is wired to J and J on the Control Board. The hot is routed directly to the compressor relay, Vacuum Pump Relay and the fan. The Hot is then protected by fuse (F), and routed through J pins and, to the T transformer. The Transformer steps the voltage down to Volts AC and it connects back to the Control Board via J8, Pins and. The Volts is then rectified and sent to voltage regulator (VR) for positive volts output, which feeds the negative volt regulator. TRANSFORMER OPERATION The step down transformer (T) converts VAC to volts AC. It is used to supply VAC to the Controller Board. SOLENOID OPERATION The term Solenoid is used here to refer to an electrically controlled pneumatic/hydraulic valve. There are three normally closed solenoids, powered by VAC. When the unit is plugged into a VAC-power source. Each solenoid is tied to a neutral line. A driver circuit on the Controller Board controls each hot line to the solenoid. When power is applied to the windings of the Solenoids, the resultant magnetic field pulls a ferrite plunger off it s seat to allow fluid flow (the valves open). COMPRESSOR OPERATION NOTE IN THE UNIT MODEL EEAC THE COMPRESSOR IS ACTIVATED, AS DESCRIBED BELOW, ALSO FOR THE VACUUM MODE. BECAUSE THE UNIT MODEL EEAC8 HAS A SEPARATE VACUUM PUMP, IT S COMPRESSOR IS USED ONLY DURING A RECOVERY MODE. In the Recovery Mode (or Vacuum Mode, see Note, above) the Compressor evacuates refrigerant from the vehicle (or, pulls a vacuum, see note, above). The Compressor is activated when the program enters the vacuum or recovery modes. The unit activates the K relay. The AC hot is then routed to the Thermal Overload Breaker (Klixon) to protect from an overload. AC hot is then routed to the "TOP PIN" of the Compressor that activates the Compressor. The start capacitor produces a phase shift allowing the Compressor to start. AC common is connected to terminal "" of the start relay coil and wiper arm on the Compressor. The wiper arm will close to terminal "" closing the circuit. The suppression cap assembly is built into the PCB to suppress noise on start up. 0/00 Page -

2 CHAPTER AC/DC POWER DISTRIBUTION VACUUM PUMP NOTE ONLY UNIT MODEL EEAC8 HAS A SEPARATE VACUUM PUMP. MODEL EEAC USES THE COMPRESSOR AS BOTH A COMPRESSOR AND A VACUUM PUMP. The Vacuum Pump is used to pull a very low vacuum on a vehicle. The Vacuum Pump used in the unit, model EEAC8, is a self contained vender item that we do not service (other than normal oil maintenance, see Chapter ). If it fails, replace it. The Vacuum Pump is feed VAC from the Control Board, via connectors J9 and 0, when a Vacuum Mode is initiated. OVERLOAD CONDITION The Thermal Overload Breaker (Klixon) is a protection device in case the current exceeds 0 amps. Once the Klixon circuit breaker trips it will reset it self after minutes. TANK FULL CONDITION The TANK FULL will be displayed when the tank reaches 80% of capacity. Once the load cell determines the weight of the tank, a signal voltage will trigger the A/D (analog to digital converter) to signal the CPU which will display TANK FULL and prevent the unit from recovering any more refrigerant. HIGH PRESSURE CONDITION High Pressure will be displayed when there is excess pressure in the Recovery Tank (>0 PSI) The High Pressure cutoff switch detects 0psi on the output side of the compressor. When high pressure is present, the high-pressure switch will open and Pressure Switch Err will be displayed. Both errors will remove all power from the compressor and solenoids. DC THEORY OF OPERATION CONTROLLER BOARD The Controller Board has three functions. ) Power supply which converts AC to DC voltages to drive the local components, LCD, Relays, Keypad, Load Cell and Transducer. ) Driver for solenoids K & K relay to energize the compressor. ) To display the programming of the software and menus via the keypad. The two supply voltages from the regulators are +VDC and VDC. The +VDC supplies voltage to the relay, while the +VDC regulator drives the load cell. The +VDC also is used to drive the LCD, and related ICs. LOAD CELL The load cell is powered by + volts DC at J0 pins and that is supplied from the + volt regulator. The cell will send a signal back through P0 pins & (Refer to Chapter, Theory Of Operation for more information) to determine the amount of weight to the A/D converter. The load cell is an electronic device that measures weight on the scale. Once the load cell reaches lbs of refrigerant, the unit will display TANK FULL. CHECK OUT PROCEDURE There is not a power supply calibration procedure for the Controller Board. The only thing available is a quick voltage check. CONTROLLER BOARD POWER CHECK OUT PROCEDURE. Using a DVM in DC mode, connect the black lead to J, on the Controller Board.. Connect the red lead to J pin on the Controller Board. Voltage reading should be +VDC ±0. volts. If not, refer to TROUBLESHOOTING Page -. Page - 0/00

3 CHAPTER AC/DC POWER DISTRIBUTION TROUBLESHOOTING COMPLAINT CORRECTIVE ACTION I. Machine will not power up. Is the machine plugged in to a VAC power source? NO > Plug machine in to a VAC power source. Is cooling fan running? NO > Check wall receptacle. NO > Check Power Cord and Power Switch. NO > Is display ON? NO > Check F on board. Verify transformer output is VAC ± VAC? NO > Replace Transformer. Replace Controller Board. II. No LCD readout. Is the power on lamp and cooling fan running? NO > Plug unit in a power source. If problem persists, refer to Complaint I. Check transformer for +VAC. Is voltage present? NO > Replace Transformer. Adjustment contrast (See Appendix G). Replace Controller Board. III. Compressor will not run. Check Display for error messages and correct those first. Check Klixon for VAC. If ok: Replace Compressor. If not: Change the Board. IV. Vacuum Pump will not run (unit model EEAC8 only) Place into a Vacuum Mode and check for VAC across terminals J9 and J0 on Control Board. Is VAC present? NO > Check or replace Control Board. YES > Check switch on Vacuum Pump, should be ON. YES > Replace Vacuum Pump. 0/00 Page -

4 CHAPTER AC/DC POWER DISTRIBUTION Page - 0/00

5 All information contained or disclosed in this document is considered confidential and proprietary by Snap-on Tools. All manufacturing, use, reproduction and sales rights are reserved by Snap-on Tools and the information contained herein shall not be used in whole or in part without the express written consent of Snap-on Tools. COMPRESSOR START RUN THERMAL OVERLOAD BREAKER AC PLUG COMPRESSOR ASSY START CAP SUPRESSION CAP ASSY START RELAY HOT NEU ON/OFF SWITCH NOTE: Only present on EEAC8 models VAC S VENT FAN VAC VAC VAC S S S PURGE SERIAL I/O PORT OIL TRANSFER VACUUM J J J 9 0 J J CONTROL BOARD S0 S N S8 LED x0 LCD Y S9 J9 J0 8 NOTE: Only present on EEAC8 models J0 J J SIGNAL +V SIGNAL VACUUM PUMP HIGH PRESSURE SWITCH (N.C.) OPTIONALVAC PUMP 0 / 0 HZ JUMPER TEMPERATURE PROBE PURGE PRESSURE TRANSDUCER T TRANSFORMER J8 J 8 8 J0 SIGNAL + EXCITATION + EXCITATION - SIGNAL - SHIELD SENSE+ SENSE- LOAD CELL JUMPERS PINS & SERVICE PINS & FACTORY PINS & IN = SUN PINS & OUT = SNAPON PINS & 8 JUMPER STORAGE MODEL: ECO XTREME REV: 0/00 REV B DWG BY: FRANK ZOFINSKI CHK BY: John Sparks MOD BY: John Sparks CHK BY: Craig Govekar TITLE: DWG: E Q U I P M E N T S E R V I C E O N S I T E Providing Factory Service For Automotive Service Equipment EquiServ Exchange Ave. Conway, AR 0 INTERCONNECT WIRING DIAGRAM PAGE: - -/