A black screen on a Colchester T200 does not by itself prove that the control has failed. In the reported case, the machine restarted and ran after the operator used the controls without a visible display. This isolates the initial symptom to the display system or its power supply, but further electrical checks are required before replacing the monitor.
Separate a Display Fault From a Control Fault
After the black-screen condition persisted through a shutdown and power-up, the machine still responded to edit, program, reset, and start commands. That behavior confirms that the control continued executing commands in this case; it does not identify whether the failed element was the monitor, an adjustment, or its power circuit.
| Observed condition | Supported conclusion | Next check |
|---|---|---|
| Black screen, but control responds | Display path or display power is suspect | Check front-panel contrast and brightness controls |
| FX14 fuse open | A fault may exist on the protected +24 V circuit | Test resistance from +24 V to ground and isolate the short |
| Adjustments and supply checks pass | Monitor failure remains a likely diagnosis | Confirm the installed monitor identity before replacement |
Check Adjustments and the FX14 Supply Circuit
- Inspect the front panel for contrast and brightness controls and adjust them through their usable range.
- With power safely isolated, check fuse FX14. The reported fuse was a 5 A Fanuc fuse associated with the machine's +24 V circuit.
- If FX14 is open, do not repeatedly replace it. A replacement that opens immediately indicates that the underlying fault remains.
- Measure resistance between +24 V and ground, then isolate branches of the machine-side wiring to locate the short circuit.
- After correcting the fault, restore power and verify that FX14 remains intact and the display returns.
The evidence does not identify the shorted component or provide an acceptable resistance threshold. Use the machine electrical documentation to divide the +24 V circuit safely and interpret the measurement.
Handle the Monitor Safely
The monitor is an open-chassis assembly with potentially hazardous voltages at its rear. Isolate power and use appropriate electrical safety procedures before opening the enclosure. Do not treat a dark screen as permission to work around the chassis while energized.
The reported replacement is a custom Fanuc monitor, part number A61L-0001-0093. The evidence explicitly states that a standard PC monitor cannot be substituted. Verify the fitted part number and connector arrangement before ordering because the evidence does not establish that every Colchester T200 configuration uses the same monitor.
Verify the Repair
Power-cycle the machine and confirm that the display initializes, remains visible, and responds to its contrast and brightness controls. If FX14 was replaced, verify that it does not open again while the machine operates. Finally, confirm that the control display and machine functions remain stable during the job cycle.
Frequently Asked Questions
Does a black Colchester T200 screen mean the control is dead?
No. In the reported case, the machine still accepted control commands and ran, indicating that the control was operating while the display remained black.
What should I check when Fanuc fuse FX14 keeps blowing?
FX14 was identified as a 5 A fuse protecting the machine's +24 V circuit. Isolate power, measure resistance from +24 V to ground, and disconnect circuit branches methodically to locate the short before installing another fuse.
Can I replace Fanuc A61L-0001-0093 with a PC monitor?
No. The evidence identifies A61L-0001-0093 as a custom Fanuc open-chassis monitor and states that a PC monitor cannot be used; verify the installed part number before ordering.
