Sirman E4

What does Sirman E4 mean?

The PLD 300-330-350 AUT control has detected a hardware-level communication failure between the operator keyboard/control panel and the power supply board. The two boards are not exchanging data correctly, which prevents safe machine operation. This is an internal electronics fault, not a mechanical or product-related issue. The manual directs the technician to investigate the communication link between these two specific PCB assemblies.

Symptoms

• Display shows 'E4' at startup or during operation
• Machine is unresponsive to keyboard inputs or behaves erratically
• Control panel may display incomplete or garbled information
• Machine does not begin any operational cycle
• Error may be intermittent if caused by a loose connector rather than a failed component

Common causes

• Communication cable or harness between the keyboard PCB and power supply PCB is loose or disconnected
• Damaged or broken communication cable/ribbon between the two boards
• Corroded or damaged connector pins on the keyboard or power supply board
• Failed keyboard PCB preventing it from communicating with the power supply
• Failed power supply PCB or its communication interface
• Electrical noise or interference disrupting the data link between the two boards

Diagnostic steps

1. 01

   Power down and access the internal electronics

   Disconnect the PLD 300/330/350 AUT from power and open the control housing per the service manual procedure to access the keyboard PCB and power supply PCB and their interconnecting harness.

2. 02

   Inspect the communication cable between boards

   Locate the cable or ribbon connecting the keyboard assembly to the power supply board. Check its full length for cuts, pinches, abrasion damage, or connector damage that would interrupt the data link.

3. 03

   Reseat both ends of the communication connector

   Disconnect and firmly reseat the communication cable at both the keyboard PCB and the power supply PCB ends. Confirm connector latches or retention mechanisms are fully engaged.

4. 04

   Inspect connector pins for corrosion or damage

   Visually examine all pins on both connectors for corrosion, bending, or breakage. Clean corroded pins carefully with appropriate electronics contact cleaner before reconnecting.

5. 05

   Power on and test for E4 clearance

   Reassemble, restore power, and observe whether E4 clears at startup and normal keyboard-to-power-supply communication is restored, allowing the machine to function correctly.

When to call a professional

If E4 persists after inspecting and reseating all communication connections, escalate immediately to a licensed Sirman service technician. A failed keyboard PCB or power supply PCB on the PLD 300/330/350 AUT requires board-level diagnosis and component replacement that must be performed by qualified personnel using genuine Sirman parts to ensure safe and correct operation.