Sega CD (Model 2) Capacitor Replacement Guide - Revision history

Josh: /* Recommended Tools & Parts */

2025-05-12T09:22:12Z

Recommended Tools & Parts

← Older revision		Revision as of 10:22, 12 May 2025
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	== Recommended Tools & Parts ==		== 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
	* ~~Quick 861-DW~~ hot-air station		* 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

Josh at 09:21, 12 May 2025

2025-05-12T09:21:02Z

← Older revision		Revision as of 10:21, 12 May 2025
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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 ==		== 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 ==		== 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 ==		== 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 ==		== Disassembly Procedure ==

	# '''Detach Genesis''' – remove side clamp & A/V bridge ribbon.		# '''Detach Genesis''' – remove side clamp & A/V bridge ribbon.
Line 138:		Line 138:
	# Desolder shield can (optional for VA0) to access C224/C225.		# Desolder shield can (optional for VA0) to access C224/C225.

	== ⚙️ Recap Best-Practices ==		== 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.
Line 146:		Line 146:
	* 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 ==		== 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 ==		== 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 ==		== Recommended Tools & Parts ==

	* JBC / Hakko FX-951 iron, hoof tip 1.5 mm		* JBC / Hakko FX-951 iron, hoof tip 1.5 mm
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	* ESR micro-meter (MESR-100 V2) for QC		* ESR micro-meter (MESR-100 V2) for QC

	== 🐾 Step-by-Step ~~(Rapid Fire)~~ ==		== 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).
	~~# Play ''Sonic CD'' intro: confirm PCM drums & CDDA vocal both audible.~~

	== 🔗 Related Pages ==		== Related Pages ==

	* [[Sega CD (Model 2)]] – full hardware spec		* [[Sega CD (Model 2)]] – full hardware spec

Josh: /* 🔗 Related Pages */

2025-05-09T14:31:18Z

🔗 Related Pages

← Older revision		Revision as of 15:31, 9 May 2025
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	* [[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]]

Josh: /* 🔍 Failure Symptoms & Tell-tale Caps */

2025-04-27T21:03:39Z

🔍 Failure Symptoms & Tell-tale Caps

← Older revision		Revision as of 22:03, 27 April 2025
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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 ==		== 📋 Capacitor BOM by Board ==

Josh: /* 📋 Capacitor BOM by Board */

2025-04-27T20:57:01Z

📋 Capacitor BOM by Board

← Older revision		Revision as of 21:57, 27 April 2025
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	\|}		\|}

	* Total electrolytics on VA0 = '''17''' (10 SMD, 7 radial).*		''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.*		'' ASIC integrates Genesis & CD logics; half the cans are deleted.''

	Key ones to replace:		Key ones to replace:

Josh at 20:56, 27 April 2025

2025-04-27T20:56:30Z

← Older revision		Revision as of 21:56, 27 April 2025
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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 dried-out surface-mount electrolytics on the main board/audio path rather than laser wear.		<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).		* '''VA0''' – early Japanese launch board (Sega part 171-5983A).
	* VA1 – worldwide production; discrete Word-RAM, ASIC 2 “315-5880”.		* '''VA1''' – worldwide production; discrete Word-RAM, ASIC 2 “315-5880”.
	* VA1.8 / VA1.9 – mid-1994, integrated “315-5933” ASIC 3 (RAM on-die).		* '''VA1.8 / VA1.9''' – mid-1994, integrated “315-5933” ASIC 3 (RAM on-die).
	* VA2 – cost-reduced Majesco / Genesis 3 bundle (CSG-MCD2 GOAC).		* '''VA2''' – cost-reduced Majesco / Genesis 3 bundle (CSG-MCD2 GOAC).

	== ⚡ Safety First ==		== ⚡ 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.
	* ESD wrist-strap – ASICs and the RF5C164 PCM DAC are MOS-based.		* '''ESD wrist-strap''' – ASICs and the RF5C164 PCM DAC are MOS-based.
	* 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 ==		== 🔍 Failure Symptoms & Tell-tale Caps ==
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	\|}		\|}

	* Total electrolytics on VA0 = 17 (10 SMD, 7 radial).*		* Total electrolytics on VA0 = '''17''' (10 SMD, 7 radial).*

	=== VA1.8 / VA1.9 Differences ===		=== VA1.8 / VA1.9 Differences ===
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	Key ones to replace:		Key ones to replace:

	* C110 (220 µF 10 V) – 5 V bulk.		* '''C110''' (220 µF 10 V) – 5 V bulk.
	* C134/C135 (47 µF 6.3 V) – audio out.		* '''C134/C135''' (47 µF 6.3 V) – audio out.
	* C301 (10 µF 16 V) – reset.		* '''C301''' (10 µF 16 V) – reset.

	== 🛠️ Disassembly Procedure ==		== 🛠️ Disassembly Procedure ==

	# Detach Genesis – remove side clamp & A/V bridge ribbon.		# '''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 flat-flex FPC from KSS-210A sled.		# 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.
Line 140:		Line 140:
	== ⚙️ Recap Best-Practices ==		== ⚙️ 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.
	* Clean pads with MG Chemicals 63/37 solder and wick.		* 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>!
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	\|unregulated from AC adapter		\|unregulated from AC adapter
	\|}		\|}
	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 ==		== 🔈 Optional Audio-Path Upgrade ==

Josh: Created page with "'''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:..."

2025-04-27T20:56:12Z

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:..."

New page

<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:

* **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%;"
!Symptom
!Culprit Cap(s)
!Explanation
|-
|Weak or missing CD audio, but FM/PSG OK
|C138, C139 (47 µF 6.3 V)
|Coupling caps between RF5C164 DAC and mixer IC inside 315-5684B.
|-
|“Checking Disc” perpetual seek after TOC read
|C224 (220 µF 16 V)
|5 V rail decoupler for CXD2510Q; ripple disrupts focus-OK interrupt.
|-
|Random freezes / garbled graphics after warm-up
|C241, C242 (100 µF 10 V)
|Word-RAM Vcc / Vss bypass; high ESR = bit-flip during DMA.
|-
|No save-RAM, “Back-up RAM Full”
|C405 (10 µF 16 V)
|V-RTC domain smoothing to SRAM + RTC; goes high-ESR → brown-out on writes.
|}

* 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 ===
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Electrolytic Capacitors – Sega CD 2 VA0/VA1'''
!Ref
!Capacitance
!Voltage
!Dia×Ht mm
!Role (rail / circuit)
|-
|C138, C139
|47 µF
|6.3 V
|5 × 5.4
|Audio L/R coupling to RGB-DAC
|-
|C148, C149
|10 µF
|16 V
|4 × 5.4
|CXD2510Q PLL & RF5C164 Vref
|-
|C224
|220 µF
|16 V
|8 × 9.5
|5 V bulk near CXD DSP
|-
|C225
|100 µF
|10 V
|6.3 × 5.4
|3.3 V (derived) for ASIC 2 core
|-
|C241, C242
|100 µF
|10 V
|6.3 × 5.4
|Word-RAM bus, 25 MHz domain
|-
|C302
|47 µF
|10 V
|5 × 5.4
|68k reset RC & IPL
|-
|C405
|10 µF
|16 V
|4 × 5.4
|Battery-backed SRAM decouple
|-
|C501
|220 µF
|25 V (radial TH)
|8 × 12.5
|Main 9 V input filter
|}

* Total electrolytics on VA0 = **17** (10 SMD, 7 radial).*

=== VA1.8 / VA1.9 Differences ===
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Additional / Changed Caps – VA1.8 & VA1.9'''
!Ref
!Old Value
!New Value
!Reason
|-
|C225
|100 µF 10 V
|47 µF 6.3 V
|ASIC 3 draws lower core current.
|-
|C330 (new)
|4.7 µF 25 V
|—
|Added to anti-alias LPF at DAC
|}

=== VA2 (Majesco) “GOAC” Board ===

* ASIC integrates Genesis & CD logics; half the cans are deleted.*

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.
# Lift bottom shell; unplug **flat-flex FPC** from KSS-210A sled.
# Unscrew 4 silver M2.6 posts; main-board comes free with lid.
# 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 **MG Chemicals 63/37** solder and wick.
* 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>!
* 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;"
|+'''Idle Rails (lid open, BIOS screen)'''
!Test Point
!Nominal
!Ripple Spec
!Notes (scope AC-coupled, 20 MHz)
|-
|5 V (IOREG pin 1)
|4.92–5.05 V
|< 25 mVpp
|feeds 68k, ASIC, drive logic
|-
|3.3 V (ASIC 2 pin 202)
|3.28–3.36 V
|< 15 mVpp
|on VA1+ only
|-
|9 V input (CN3)
|9.0–9.3 V
|–
|unregulated from AC adapter
|}
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 %.
* 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
* Quick 861-DW hot-air station
* No-clean flux pen, solder wick 2.0 mm
* Nichicon UFW / Panasonic FR electrolytics 105 °C
* TI TPS5430 buck (optional – replace linear 7805 to drop heat by 4 °C)
* ESR micro-meter (MESR-100 V2) for QC

== 🐾 Step-by-Step (Rapid Fire) ==

# Remove SMD caps → clean → inspect pads under microscope.
# Install new caps smallest → largest to avoid crowding.
# Replace radial C501 last; retin with 0.8 mm solder for strength.
# Wash board in IPA, blow-dry, leave 30 min.
# Re-assemble, run BIOS memory test (hold A+B+C+Start on power-up).
# Play ''Sonic CD'' intro: confirm PCM drums & CDDA vocal both audible.

== 🔗 Related Pages ==

* [[Sega CD (Model 2)]] – full hardware spec
* [[Sega CD (Model 2) Troubleshooting Guide]]
* [[Sega Genesis (Model 2) General Maintenance]]