Lexmark W820 Service Manual page 175

Step Actions and Questions
Steps 4 through 11 attempt to find a faulty printer FRU that may be generating electrical noise. If replacing
a FRU does not solve the problem, reinstall the old FRU before moving on to the next step.
4 EP CARTRIDGE REPLACEMENT
Replace the EP Cartridge.
Is the Electrical Noise problem still present?
5 HVPS REPLACEMENT
Replace the "High Voltage Power Supply (HVPS)
Assembly" on page 4-88
Is the Electrical Noise problem still present?
6 AC DRIVER REPLACEMENT
Replace the "AC Driver PWB 120/230 VAC" on page
Is the Electrical Noise problem still present?
7 LVPS ASSEMBLY REPLACEMENT
Replace the "Low Voltage Power Supply (LVPS) Assembly"
on page 4-82
Is the Electrical Noise problem still present?
8 FUSER ASSEMBLY REPLACEMENT
Replace the "Fuser Assembly" on page
Is the Electrical Noise problem still present?
9 MCU PWB REPLACEMENT
Replace the "Engine Board (MCU PWB)" on page
Is the Electrical Noise problem still present?
10 MAIN DRIVE ASSEMBLY REPLACEMENT
Replace the "Main Drive Assembly" on page 4-79
Is the Electrical Noise problem still present?
11 The following FRUs are associated with this specific problem.
One or more of these FRUs may have failed partially or
completely. If you cannot isolate the problem using this Service
Check, replace each FRU listed below, one at a time, until the
problem disappears.
• Lift Motors - Go to
• Feed Clutches - Go to
• Printhead Assembly - Go to
page 4-57.
• Offset Unit - Go to
• ESS PWB - Go to
page 4-94.
• I/O PWB - Go to
4025-XXX
"Tray 1 Lift Motor" on page
"Tray 1 Feed Clutch" on page
"Printhead Assembly" on
"Offset/Exit Assembly" on page
"Controller Board (ESS PWB)" on
"I/O PWB" on page 4-89.
Yes
Go to step 5
Go to step 6
Go to step 7
4-86.
Go to step 8
Go to step 9
4-65.
Go to step 10
4-92.
Go to step 11
4-13.
4-14.
4-69.
No
Problem
solved
Problem
solved
Problem
solved
Problem
solved
Problem
solved.
Problem
solved
Problem
solved
Diagnostic Information
2-79