Diagnosing Epson L1800 Driver Chip Issues: Common Errors and Advanced Testing
- By Kevin Day
- On Dec 23, 2024
- Comment 0
Question:
I followed BCH Technologies' video to test the mainboard transistors and driver chips in my Epson L1800 DTF printer. All the ground points that should beep did so during the test. Is it still possible that the driver chip could be faulty even if it tests as good?
Answer:
Thank you for reaching out and for your detailed question. I'm sorry for not getting back to you sooner. I understand how urgent printer issues can be and am glad to assist you. We’re grateful for your engagement at BCH Technologies, particularly with our YouTube channel (https://youtube.com/@bchtechnologies). Your feedback helps us refine our technical resources and better support our community.
To address your question, a driver chip can test as good with a multimeter but still malfunction under load. When testing with a multimeter, you only assess its static state, not its behavior under operating conditions. Once powered with 42V and actively driving signals, subtle failures may surface. Below are some detailed explanations and testing techniques to diagnose the issue further:
Thank you again for your inquiry. Your support is invaluable, and I hope this guidance helps you troubleshoot your printer effectively. Feel free to let us know if you need any more help!
I followed BCH Technologies' video to test the mainboard transistors and driver chips in my Epson L1800 DTF printer. All the ground points that should beep did so during the test. Is it still possible that the driver chip could be faulty even if it tests as good?
Answer:
Thank you for reaching out and for your detailed question. I'm sorry for not getting back to you sooner. I understand how urgent printer issues can be and am glad to assist you. We’re grateful for your engagement at BCH Technologies, particularly with our YouTube channel (https://youtube.com/@bchtechnologies). Your feedback helps us refine our technical resources and better support our community.
To address your question, a driver chip can test as good with a multimeter but still malfunction under load. When testing with a multimeter, you only assess its static state, not its behavior under operating conditions. Once powered with 42V and actively driving signals, subtle failures may surface. Below are some detailed explanations and testing techniques to diagnose the issue further:
Why Driver Chips May Fail Dynamically
- Partial Damage: Sometimes, a damaged driver chip may not exhibit an open or short circuit during static tests but could fail when processing dynamic signals. This often leads to nozzle misfires, erratic printing patterns, or uneven ink deposition.
- Load Sensitivity: Driver chips that work fine without a load may fail when driving a printhead. Symptoms include misfiring nozzles, stray ink lines, or blobs.
- Gate Control Failures: Driver chips control gates for ink release. If a gate remains open, ink may spray continuously, overheating the printhead and worsening the chip’s condition.
Advanced Testing Tools and Methods
Oscilloscope Testing:
To analyze the pulse signals from the driver chip, use an oscilloscope with a high-voltage probe or a differential probe. The oscilloscope can visualize pulse amplitude, frequency, and duty cycle, revealing subtle issues. Suggested models include:- Rigol DS1054Z or Siglent SDS1202X-E (50 MHz bandwidth recommended).
- High-voltage probes like the Micsig DP10013 or Siglent DPB5150 are ideal for safely measuring voltages up to 70V.
Logic Analyzer Testing:
If waveform visualization isn’t required, a logic analyzer can help capture and decode digital pulses. Devices like the Saleae Logic Pro 8 can monitor timing, pulse width, and integrity. For safety, ensure that a voltage divider or level shifter is used to bring 42V pulses down to TTL levels.Differential Probes:
Differential probes are particularly useful for floating measurements where no common ground exists. They’re essential for directly analyzing high-side signals from driver chips.Steps to Diagnose Further
- Test with a Known Good Printhead: Connect a functional L1800 printhead (even if partially clogged) to the mainboard. Persistent issues indicate a mainboard fault.
- Bypass Conversion Boards (if applicable): If you’ve converted your L1800 to an L805, disconnect the conversion board and connect the printhead directly to eliminate interference.
- Inspect for Heat or Burn Marks: Examine the mainboard for scorched components, swollen capacitors, or discoloration that may signal driver chip damage.
- Replace the Driver Chip or Mainboard: If no visible damage exists but errors persist, replacing the driver chip or sending the mainboard for repair may resolve the problem. For professional diagnostics, you can use our printer repair service (https://bchtechnologies.com/printer-repair-service).
Common Misconceptions
- The CRPW cable (carriage position and paper width sensor) does not influence nozzle misfires or printhead operation. If the carriage and paper feed systems are functional, the problem likely lies elsewhere.
Thank you again for your inquiry. Your support is invaluable, and I hope this guidance helps you troubleshoot your printer effectively. Feel free to let us know if you need any more help!