LaserActive:PAC-S10 Audio Circuit Service Bulletin Update

According to a service bulletin from Pioneer, early revisions of the PAC-S10 and S1 needed adjustments to the audio circuit to avoid distorting high frequency audio "when a certain Sega game software is played." However, this distorted audio affects all games and it is recommended to perform the resistor/capacitor replacements.

MDFourier Plots

• 

  MDFourier plot, pre-fix

• 

  MDFourier plot, Post-fix

Installation

You will need the following parts for this modification:

• 33K 0805 1/10W+ Resistor (Qty 4)
• 100K 0805 1/10W+ Resistor (Qty 2)
• 27K 0805 1/10W+ Resistor (Qty 2)
• 22K 0805 1/10W+ Resistor (Qty 2)
• 3.3K 0805 1/10W+ Resistor (Qty 2)
• 120pF 0805 25V+ Capacitor (Qty 2)
• 820pF 0805 25V+ Capacitor (Qty 2)

Note: The bulletin also indicates that the large surface mount electrolytic AC coupling caps (C117 and C21) are to be replaced with 1 uF, 50V rated caps. This is not required, but recommended.

Replace the parts indicated as directed in the list below:

• 

  Service Bulletin Audio Circuit Schematic

• 

  Parts to be replaced, highlighted

Using the parts above, replace the parts as indicated:

• R31, R58, R32, R59 - 33K
• R33, R34 - 100K
• R131, R52 - 27K
• R38, R40 - 22K
• R39, R41 - 3.3K
• C16, C17 - 120pF
• C33, C34 - 820 pF