Fix thermal-pressure motor lock

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This tutorial provides step-by-step instructions to replace a broken gear powered by the Thermal Pressure Motor. This process applies to most Riso Z-type (and beyond ) duplicators and is demonstrated here on an MZ1070. The error messages "T19-208" or similar codes such as "T19-XXX" may indicate the need for this replacement.

Overview

The gear in question is prone to wear over time. Replacement gears, such as part #612-10010, are commonly available on platforms like AliExpress or eBay. It is recommended to acquire the replacement part before beginning the procedure.

Configure

Step 1: Remove the outer cover of the Master Removal Unit (feed side)

- Unscrew and remove the outer cover (5 screws in total). The left side may be slightly hooked.

Step 2: Remove the top cover of the paper feed

- Unscrew and remove the plastic cover (2 screws). Pull the cover towards you and set it aside.

Step 3: Disconnect cables and remove the Master Removal Unit

- Unplug 2 cables and the connector. Remove the cable clamp. - Unscrew 2 screws holding the Master Removal Unit in place. - Carefully pull the unit out; it is heavy.

Step 4: Push the MMU towards the paper feed side

- Open the cover of the Master Making Unit (MMU) and push the MMU towards the opposite side. If it doesn’t move, proceed to the next step.

Step 5: Press the plastic hook to advance the MMU

- Push the hook to allow the MMU to slide further into the machine.

Step 6: Push the MMU all the way in

- Continue pushing the MMU until it stops.

Step 7: Remove screws from the Thermal Pressure Gear Cover

- From the paper feed side, unscrew 2 screws. Hold the MMU to prevent it from sliding back.

Open and disassemble the MMU

Step 8: Remove the MMU bottom cover

- Unscrew 2 screws and set the cover aside.

Step 9: Remove the TPH

- Avoid touching the TPH stripe (yellow/orange color). - Remove the black plastic snap ring and spring. - Lift and remove the top bronze bearing metal. - Unplug 2 cables connected to the TPH. - Carefully lift the TPH while holding the lower bronze bearing metal.

Step 10: Unscrew the earthing

- Hold the TPH and unscrew the earthing screw, ensuring it does not fall inside the MMU.

Step 11: Remove the top screws of the Thermal Pressure Gear Cover

- Unscrew the top 2 screws to remove the cover.

Inspect and replace the gear

Step 12: Check the gear

- Inspect the gear for damage. If it is intact, the issue may be elsewhere.

Step 13: Remove springs from the fulcrum shaft

- Remove the springs with care, as they are under tension.

Step 14: Remove e-rings from the fulcrum shaft

- Use pliers or a screwdriver to carefully remove the e-rings, as they are tight.

Step 15: Remove the fulcrum shaft

- Extract the shaft to access the gear.

Step 16: Remove broken gear and related components

- Unscrew the white plastic piece and any remaining gear fragments. - Remove the tiny e-ring and push the shaft to the left.

Step 17: Install the new gear

- Slide the new gear onto the shaft. - Reassemble the shaft and ensure the white plastic piece faces inward.

Step 18: Reassemble

- Grease the new gear and reassemble all components in reverse order.