Service SKBIF / LCD Monitor - Troubleshooting Guide - NGC
Last updated: 07/07/2020

SKBIF / LCD Monitor - Troubleshooting Guide - NGC

Introduction

[1] 15" LCD.

[2] 15" Touchscreen LCD.
NOTE: Not all machines are equipped with the LCD touchscreen.  The LCD touch screen has a USB cable that plugs into the SKIBF PCB.  

[3] SKBIF PCB

[4] Handle Jog

[5] E-Stop Button

[6] Power Off

[7] Power On

Symptom Table

Symptom Possible Cause Corrective Action
Machines with SKBIF Version 6.xx.  Alarm 546 SERIAL KEYBOARD COMMUNICATION FAULT. The SKBIF firmware is outdated. Make sure you have SKBIF firmware version 6.6 or higher.  Refer to SKBIF PCB / RJH Firmware Update - NGC procedure.
The LCD turns to a black screen. Alarm 967 SKBIF COMMUNICATION FAULT. There is a problem with the communication cable from Main PCB to SKBIF PCB. See SKBIF Troubleshooting section below.
The supply voltage from PSUP PCB to SKBIF PCB is not correct.
The backlight and LCD data cables are not connected correctly.
The wires to the [POWER ON], [POWER OFF], [EMERGENCY STOP], [FEED HOLD] and [CYCLE START] contactors terminals are loose.
The beacon light does not turn on. The beacon light cable is not connected. Make sure the beacon light is connected to SKBIF at P10.
The control has a blurry screen.

A switch on the SKBIF is not correctly set.

 Change the MAPSEL switch to the opposite position. See the section below.
The screen flickers during spindle deceleration (running spindle then pressing "Reset" key) or during heavy cuts. The cable from the Maincon PCB connected J9 to the SKIBF at J28 is defective.
  1. Check the RJ-45 cable connection from Maincon PCB (J9) to SKIBF PCB (J28). To test the cable refer to Network Cable Tester Tool procedure.
  2. Inspect the RJ-45 connector housing on the Maincon PCB & SKIBF PCB for bent pins.
The RJ-45 connector housing is damaged on the SKIBF or Maincon PCB. Make sure the RJ-45 connector housing is solder to the PCB and not loose.
You get a blank screen with continuous beeping at power on. The jog handle or wiring is defective.
  1. Power off the machine.
  2. Check the wiring to the jog handle, make sure all the cables are connected in the correct location.
  3. Set the meter to ohms, measure resistance between front panel ground to the +5Vdc of jog handle - it should not read zero ohms. If shorted, disconnect the +5Vdc wire from the Jog Handle and check if the problem is the jog handle or the SKIBF.
Machines with software version prior to 100.17.000.2034 . The control freezes, blank monitor, black screen, keypad not working, won't boot sometimes, random shutdowns, or software alarms. Caused by a software error. Refer to the: Next Generation Control - Maincon / Software Update Troubleshooting Guide
Alarm 2001 EMERGENCY STOP SWITCH ERROR
 There is a loose connection from the E-stop button to the SKBIF PCB.
  1. Go to Diagnostic Page --> Keyboard I/O
  2. Type REDUNDANT_ESTOP then press [F1].
  3. With [EMERGENCY STOP] released the INPUT #26 REDUNDANT _ESTOP value should = 1.
  4. Press [EMERGENCY STOP].  The INPUT #26 REDUNDANT _ESTOP value should = 0. If it remained = 1 check the cable plug to SKBIF J26 see diagrams located at the end of this Troubleshooting Guide.
LCD Touchscreen.  Turned setting 381 to On, but the touchscreendoes not respond to touch commands. The touchscreen feature is not enabled. To enable the Touchscreen set setting 381 Enable Touchscreen to On.
The configuration files are outdated. As of software version 100.19.000.1400 or higher a parameter 2257 Touchscreen Suport has been added, this parameter must be set to TRUE.  If not you will need to contact the service department to have it enabled.
LCD Touchscreen
The TouchScreen does not respond to touch commands.		 The touchscreen feature is not enabled. To enable the Touchscreen set setting 381 Enable Touchscreen to On.
The touchscreen is not calibrated. Use the touchscreen configuration page to calibrate, test, and restore default settings.
The touchscreen configuration is located in the maintenance section.
Press [DIAGNOSTIC] to go to the Maintenance and navigate to the Touchscreen tab. 
Follow the instructions on the screen.  After calibration you need to cycle power.
The touchscreen USB cable is not connected correctly to the SKBIF PCB. Make sure that the USB cable connection is connected to J21 at SKBIF PCB.
LCD TouchScreen.
Some tabs look dark as they have been pushed.		 This is normal,  this is used to distiguish the family of tabs the current screen is showing.
The sound of the beeper only works when I power on the machine. The beeper volume setting is turned off. Go to setting 356 and set to a value higher than 0.
The beeper volume is low or inaudible. The SKIBF PCB or beeper is defective. Machines with SKBIF (34-4510) PCB the beeper is built into the SKIBF.  This beeper can not be tested,  check for voltage going to the SKIBF, if everything checks out ok then the SKIBF PCB is defective. Note:  Do not replace the speaker,  the speaker does not produce the beeper sound.

Machines with SKIBF  (34-4243G) PCB the beeper is mounted outside and connected to the SKIBF.  This beeper can tested with a 9V battery.

SKBIF Troubleshooting

  1. Remove the LCD back cover.
  2. Check J13 backlight and J16 LCD data connectors. Make sure the connectors are seated, and wires are not broken.
  3. Check the wires going to the [POWER ON], [POWER OFF], [EMERGENCY STOP], [FEED HOLD] and [CYCLE START] 
    contactors. Make sure the connections are tight.
  4. Look at the status LED lights.  Refer to the LED table below.
  5. Set the volt meter to DC. Check for +12Vdc supply voltage at J20 you should measure approximately +12Vdc. If this voltage is lower than +11Vdc or not present make sure J20 connector is properly seated, and trace the voltage back to the LVPS. Refer to the above electrical diagram.
  6. The SKBIF PCB generates +3.3Vdc, +5Vdc. Check these voltages at the following test points (TP).
    • Put the black probe at TP(GND) and the red probe at TP (+3.3Vdc) you should measure approximately +3.3Vdc.
    • Put the black probe at TP (GND) and the red probe at TP (+5Vdc) you should measure approximately +5Vdc.
    • Put the black probe at TP (GND) and the red probe at TP (+12Vdc) you should measure approximately +12Vdc.

    If these voltages are low or no voltage is measured, disconnect all the connectors from the SKBIF PCB except the J20 connector, and measure again. If after doing this there is still no voltage then the SKBIF PCB is defective.

    If after disconnecting the components, the voltages are correct, then there is a short circuit in one of the components connected to the SKIBF for example, remote jog handle, handle Jog, etc. Determine which component is at fault.

LED table

The following table applies to -4243G SKIBF PCB.

LED# Status Corrective Action
LE1 (PASS/EQ, Lock) Amber This is normal condition. The SKBIF and Main PCB are communicating.
LE3 Sync Green
LE1 (PASS/EQ, Lock) Red The communication between the Main PCB and SKBIF PCB is lost or no signal. Check the RJ45 cable connected to SKIBF at J28 to Main PCB J9, make sure the cable is not damaged or it has a loose connection.
LE3 Sync OFF

Blurry Screen - Dip Switches

Corrective Action: Locate the MAPSEL / S1 dip switch on the SKBIF PCB. Switch the dipswitch to the opposite position.

PCB Component Inspection

Intermittent symptoms or alarms can be caused by component failure. Below is a list of possible failures:

  1. Missing solder on all or some components pins
  2. Poor solder
  3. Solder bridges
  4. Wrong component installation (orientation)
  5. Missing components

     Note: Some PCB's have unused circuits and are missing components intentionally, look for broken off components.

  6. Broken components
  7. Broken pins on IC's
  8. Bent pins on the connectors

Use a magnifying glass to inspect the circuit components on the front and back of the SKIBF PCB. Below are the circuit component zones to inspect:

  1. Inputs connectors (Keyboard, E-stop, Power On/OFF etc.)
  2. RJ-45 connector (SKIBF PCB communication with Maincon PCB, LCD Data)
  3. LCD circuit components (LCD Backlight, LCD Data).
  4. Inspect all solder joints for missing solder.

 Important: If you find a damaged component, replace the SKIBF PCB, inspect the new SKIBF PCB circuit components before installing.

Electrical Diagrams

SKIBF / LCD Interconnect Diagram

Pendant E-stop Circuit Diagram

PSUP (P16) to SKIBF (J20) / SKIBF (J5) Detail Diagram

PSUP (P17) to I/O PCB (P56) Detail Diagram

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