LaserActive:PAC-S10 - Various Issues and Solutions

This page details several faults discovered while servicing various PAC-S10/S1 modules and their solutions.

Post-Recap Short Circuit Check
After performing any capacitor replacement work, it is imperative to check the three voltage rails (+5, +8, -8) for short circuits. If there is a short circuit on any of these rails, it will damage the CLD-A100 player. Both the MAIN and SUB boards have fuses that are labeled with the voltages they protect on the back side of each board. Check that these are not shorted to Ground on BOTH boards. Also note that the SUB board has two grounds - one for digital and one for audio. The fused 5V rail is referenced to the digital ground and can be checked by measuring continuity to the ground on C506.

Blank Screen on Power Up - Cartridges and BIOS do not load
Assuming no short circuits were measured across any voltage rail on the PAC, one root cause for this issue is the "D15" signal (IC1, Pin 32) being severed. This trace runs directly under C302, which has likely corroded the trace after years of being exposed to electrolytic fluid.

Restore the signal by reconnecting Pin 32 to the plated via next to the "40" text, adjacent to the BIOS EEPROM.

Missing/No Sound In Certain Games, Cannot boot Master System games
This is due to a missing data line from the Z80 CPU to the Sega 315-5660 ASIC. C129 is near the lines for D13-15 vias from the Z80 to the 5660 and C111 is near D5-7, increasing the probability of damage from extended exposure to leaked electrolytic fluid. First discover where the signal is lost and then jump the signal to the appropriate trace.

Horizontal Color Smearing
The PAC-S10/S1 employs separate voltage regulators to bias the emitter follower buffers for the RGB signals. The trace that provides voltage to the RED signal buffer is adjacent to C453, which is prone to heavy leakage and can sever the +5V regulated voltage line. This repair can be accomplished by using a thin gauge wire/component lead to jump the top side metal to the bottom side, or a wire can be used to directly jump the signal via the component pads as shown.