Subject: Circuit Board troubleshooting Bulletin

Transcription

1 Subject: Circuit Board troubleshooting Bulletin Problem Statement: The heater lead connections on circuit board (PN ) used on many 208 or 240 volt LAC, LBB, LCC, LCD, RAD, and RFD Despatch ovens may come loose over time. This can cause an overheat condition at the terminal and can cause the terminal to fail. Circuit board inspection and repair/replacement is recommended. Scope: Specific models that this bulletin refers to are: RAD1-42, RFD1-42, LCC1-16, LCC1-51, LCD1-16, LCD1-51, all LBB models, LAC models ending in -5, -6, or -7 Inspection 1. Tool required a. Screwdriver b. Cutter or Stripper c. Electrical tape d. Multi-meter e. Solder iron f. Solder g. Notebook and pen 2. Cool down your oven to IDLE, Turn main breaker to OFF position to shut off your oven. Lock out power.

2 3. Remove screws to open the electrical compartment or remove control panel. 4. Open the cabinet door or remove control panel to access the circuit board 5. For safety reasons, verify the inlet voltage is ZERO before doing any work. 6. Inspect the circuit board heater lead wire connection terminals condition. The fiberglass insulated heater lead wires are connected with spade connectors on the side of the long side of the circuit board.

3 There are 4 scenarios you may see: A. Terminations are in as new condition. B. Terminations have slight discoloration. C. Circuit board has a green screw terminal block instead of spade connectors. Green Screw Terminals Spade connectors D. The connector is melting damaged by arcing.

4 Actions: For scenario A and B, you need to do simple repair immediately. a. Pull out the wires 1H1 and 1H2 from board b. Strip the half plastic from female terminals and then re-terminate to board. Ensure all terminals connected tightly c. Solder the Female/male terminals together being careful to not overheat the spade on the board.

5 d. Insulate the terminals with electrical tape. e. Make sure all your tools are removed from cabinet and then close the door. f. Restart oven and ensure it is operating properly. For scenario C, the circuit board has already been replaced. No additional action required. For scenario D, contact Despatch Parts department at for part replacement. Be ready to provide model# and Serial# when ordering the replacement board. Instructions for replacement part are listed below.

6 Circuit board replacement procedure: a. Repeat steps 3-6 listed above to access panel and verify ZERO voltage. b. Check all connected wires/connectors to ensure they are labeled before disconnecting. c. Remove Timer TDR1 and relay 3CR (if present). Save them for new board installation. d. Pull out wire connectors J50, J51, and J52.

7 e. Remove inlet power cable L1 and L2. f. Record the 4 FUSE Amperage and location. Remove and save for installation on new board. g. Remove cable 3L1 and 3L2.

8 h. Remove cable 4L1 and 1H1 from Solid State Relay. Relay will look different for different model ovens. i. Remove termination 1H1 and 1H2 and then remove 4 corner screws allowing the removal of the circuit board.

9 j. Verify all jumpers J1 J7 of new board are same as old one. k. Fit new board into right position and tighten the 4 corner screws. l. Connect cable 4L1 and 1H1 to Solid State Relay.

10 m. Put back wires 3L1, 3L2, L1 and L2. n. Put back connectors J50, J51 and J52. Make sure the wire number fit in right position follow the numbers nearby the terminals. o. Remove the female terminal from 1H1 and 1H2, strip the wire and then connect to 1H1 and 1H2 position.

11 p. Install FUSE to right position follow your record. q. Install Relay 3CR and Timer TDR 1 (if present). r. Verify all connection correct and solid tight s. Verify remove all your tools out of cabinet. t. Close the door and turn on main switch.

12 u. Heat your oven as normal production. v. Monitor for 30 minutes to make sure there is nothing abnormal happens.