Sega CD (Model 2) Capacitor Replacement Guide: Difference between revisions
Created page with "<templatestyles src="Template:StyledTable/styles.css" />'''Recapping a Mega-CD 2 / Sega CD 2 is the single most effective long-term reliability upgrade you can perform.''' The top-loader’s Sony KSS-210A pickup is robust; 95 % of “no-boot” or “no audio” failures traced in 2020-2024 community surveys were caused by **dried-out surface-mount electrolytics** on the main board/audio path rather than laser wear. This guide targets every known motherboard variant:..." |
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<templatestyles src="Template:StyledTable/styles.css" />'''Recapping a Mega-CD 2 / Sega CD 2 is the single most effective long-term reliability upgrade you can perform.''' The top-loader’s Sony KSS-210A pickup is robust; 95 % of “no-boot” or “no audio” failures traced in 2020-2024 community surveys were caused by | <templatestyles src="Template:StyledTable/styles.css" />'''Recapping a Mega-CD 2 / Sega CD 2 is the single most effective long-term reliability upgrade you can perform.''' The top-loader’s Sony KSS-210A pickup is robust; 95 % of “no-boot” or “no audio” failures traced in 2020-2024 community surveys were caused by '''dried-out surface-mount electrolytics''' on the main board/audio path rather than laser wear. | ||
This guide targets every known motherboard variant: | This guide targets every known motherboard variant: | ||
* | * '''VA0''' – early Japanese launch board (Sega part 171-5983A). | ||
* | * '''VA1''' – worldwide production; discrete Word-RAM, ASIC 2 “315-5880”. | ||
* | * '''VA1.8 / VA1.9''' – mid-1994, integrated “315-5933” ASIC 3 (RAM on-die). | ||
* | * '''VA2''' – cost-reduced Majesco / Genesis 3 bundle (CSG-MCD2 GOAC). | ||
== | == Safety First == | ||
* | * '''Unplug the PSU''' – the MK-1602 adaptor can source >1 A; charged input caps may hold 30 V for minutes. | ||
* | * '''ESD wrist-strap''' – ASICs and the RF5C164 PCM DAC are MOS-based. | ||
* | * '''Iso-alcohol only''' (≥91 %) for board wash; avoid acetone (melts silk). | ||
== | == Failure Symptoms & Tell-tale Caps == | ||
{| class="wikitable styled-table" style="width:98%;" | {| class="wikitable styled-table" style="width:98%;" | ||
!Symptom | !Symptom | ||
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|} | |} | ||
''Grey, crusty SMD cans <u>do not always bulge</u>; an ESR meter (> 15 Ω @ 100 kHz) is the sure diagnosis.'' | |||
== | == Capacitor BOM by Board == | ||
=== VA0 / VA1 Main-Board === | === VA0 / VA1 Main-Board === | ||
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''Total electrolytics on VA0 = '''17''' (10 SMD, 7 radial).'' | |||
=== VA1.8 / VA1.9 Differences === | === VA1.8 / VA1.9 Differences === | ||
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=== VA2 (Majesco) “GOAC” Board === | === VA2 (Majesco) “GOAC” Board === | ||
'' ASIC integrates Genesis & CD logics; half the cans are deleted.'' | |||
Key ones to replace: | Key ones to replace: | ||
* | * '''C110''' (220 µF 10 V) – 5 V bulk. | ||
* | * '''C134/C135''' (47 µF 6.3 V) – audio out. | ||
* | * '''C301''' (10 µF 16 V) – reset. | ||
== | == Disassembly Procedure == | ||
# | # '''Detach Genesis''' – remove side clamp & A/V bridge ribbon. | ||
# Flip the CD unit; extract the 6 self-tapping screws. | # Flip the CD unit; extract the 6 self-tapping screws. | ||
# Lift bottom shell; unplug | # Lift bottom shell; unplug '''flat-flex FPC''' from KSS-210A sled. | ||
# Unscrew 4 silver M2.6 posts; main-board comes free with lid. | # Unscrew 4 silver M2.6 posts; main-board comes free with lid. | ||
# Desolder shield can (optional for VA0) to access C224/C225. | # Desolder shield can (optional for VA0) to access C224/C225. | ||
== | == Recap Best-Practices == | ||
* | * '''Hot air @ 260–280 °C''' + thin tweezers; twist, do '''not''' pry. | ||
* Clean pads with | * Clean pads with '''MG Chemicals 63/37''' solder and wick. | ||
* Replace with '''polymer aluminium''' or '''solid tantalum''' where < 100 µF (audio) – lowers ESR ≤ 0.05 Ω. | * Replace with '''polymer aluminium''' or '''solid tantalum''' where < 100 µF (audio) – lowers ESR ≤ 0.05 Ω. | ||
* Observe polarity: white stripe = negative on original cans; polymer “stripe” is <u>positive</u>! | * Observe polarity: white stripe = negative on original cans; polymer “stripe” is <u>positive</u>! | ||
* Keep lead-spacing 2.0 mm; VA1 vias rip easily if enlarged. | * Keep lead-spacing 2.0 mm; VA1 vias rip easily if enlarged. | ||
== | == Post-Recap Voltage / Ripple Check == | ||
{| class="wikitable styled-table" style="width:85%; text-align:center;" | {| class="wikitable styled-table" style="width:85%; text-align:center;" | ||
|+'''Idle Rails (lid open, BIOS screen)''' | |+'''Idle Rails (lid open, BIOS screen)''' | ||
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|unregulated from AC adapter | |unregulated from AC adapter | ||
|} | |} | ||
If ripple ≥ 60 mV after recap → suspect | If ripple ≥ 60 mV after recap → suspect '''PF1 poly-fuse''' fatigue or failing PSU capacitors (replace 2× 2200 µF 16 V inside MK-1602 brick). | ||
== | == Optional Audio-Path Upgrade == | ||
* Swap C138/C139 to '''Nichicon UQZ 47 µF 16 V polymer''' – THD < 0.02 %. | * Swap C138/C139 to '''Nichicon UQZ 47 µF 16 V polymer''' – THD < 0.02 %. | ||
* Bypass internal mixer and route RF5C164 + YM3438 through a “Triple-Bypass” daughter-card for pristine 1.2 Vp-p RGB + line-level-2 Vrms audio. | * Bypass internal mixer and route RF5C164 + YM3438 through a “Triple-Bypass” daughter-card for pristine 1.2 Vp-p RGB + line-level-2 Vrms audio. | ||
== | == Recommended Tools & Parts == | ||
* JBC / Hakko FX-951 iron, hoof tip 1.5 mm | * JBC / Hakko FX-951 (or other tempreture controlled) soldering iron, hoof tip 1.5 mm | ||
* | * Tempreture controlled hot-air station | ||
* No-clean flux pen, solder wick 2.0 mm | * No-clean flux pen, solder wick 2.0 mm | ||
* Nichicon UFW / Panasonic FR electrolytics 105 °C | * Nichicon UFW / Panasonic FR electrolytics 105 °C | ||
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* ESR micro-meter (MESR-100 V2) for QC | * ESR micro-meter (MESR-100 V2) for QC | ||
== | == Step-by-Step == | ||
# Remove SMD caps → clean → inspect pads under microscope. | # Remove SMD caps → clean → inspect pads under microscope. | ||
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# Wash board in IPA, blow-dry, leave 30 min. | # Wash board in IPA, blow-dry, leave 30 min. | ||
# Re-assemble, run BIOS memory test (hold A+B+C+Start on power-up). | # Re-assemble, run BIOS memory test (hold A+B+C+Start on power-up). | ||
== | == Related Pages == | ||
* [[Sega CD (Model 2)]] – full hardware spec | * [[Sega CD (Model 2)]] – full hardware spec | ||
* [[Sega CD (Model 2) Troubleshooting Guide]] | * [[Sega CD (Model 2) Troubleshooting Guide]] | ||
* [[Sega Genesis (Model 2) General Maintenance]] | * [[Sega Mega Drive / Genesis (Model 2) Maintenance Guide|Sega Genesis (Model 2) General Maintenance]] | ||
[[Category:Capacitor Replacement Guides]] | |||
[[Category:Sega Systems]] | |||