Sega CD (Model 2) Capacitor Replacement Guide: Difference between revisions
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* '''VA2''' – cost-reduced Majesco / Genesis 3 bundle (CSG-MCD2 GOAC). | * '''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. | * '''Unplug the PSU''' – the MK-1602 adaptor can source >1 A; charged input caps may hold 30 V for minutes. | ||
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* '''Iso-alcohol only''' (≥91 %) for board wash; avoid acetone (melts silk). | * '''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.'' | ''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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* '''C301''' (10 µF 16 V) – reset. | * '''C301''' (10 µF 16 V) – reset. | ||
== | == Disassembly Procedure == | ||
# '''Detach Genesis''' – remove side clamp & A/V bridge ribbon. | # '''Detach Genesis''' – remove side clamp & A/V bridge ribbon. | ||
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# 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. | * '''Hot air @ 260–280 °C''' + thin tweezers; twist, do '''not''' pry. | ||
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* 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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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). | 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]] | |||