Hobbyist Components List for Sega Genesis Model 1 Units 2019/11/19-21 by Ami Sapphire Updated: 2021/10/28 2019 [1205] Headphone Amp Replacement List Update [1206] Video RAM Specification Update Diode List Update Various things changed from Alternates to Variations in Specific Components List Variations = Components that were installed from the factory Alternates = Components that were not installed from the factory, but may work with the unit Changed Z80 and Z80 RAM to Sound and Sound RAM as CPU spec name Capacitor Recommended Series Replacement Update [1207] More Capacitor Recommended Series Replacement Update Corrected Labeling of Capacitor Numbering for various Model 1 Genesis board variations Added 10uf 25V capacitor value for VA3 Model 1 boards [1210] Fixed recent 47uf 10V/16V capacitor quantity discrepancy for VA5/VA6/VA6.x boards Added 47uf 16V capacitor value for VA3 Model 1 boards Fixed long-running 100uf 10V capacitor quantity discrepancy introduced in mid-late November D2 is identified, thanks to a Model 1 VA6.5 PAL Genesis schematic; replacements are noted [1211] Even More Capacitor Recommended Series Replacement Update Added IC number designations marked on PCB for each IC listed (unfinished) [1213] Continuation of IC number designations marked on PCB for other components (finished) General spelling/typo corrections [1214] Corrected type of switch for reset button Finally have proper measurements for reset button [1215] Another SRAM chip added to Variations sub-entry of Sound RAM Alternate part for 7805 voltage regulators (also a clarification) Fixed egregious VRAM total amount: 256KB -> 64KB Fixed egregious Sound SRAM total amount: 64KB -> 8KB Added LM358 variation: ST LM358N [1216] Fixed row spacing for socket mod component Sony CXA1145P: 300mil -> 400mil [1224] Document alternate resistor location on main 68000 CPU (NMOS versions) of VA3 motherboard revisions Note resistor pack on VA3 motherboard revisions located on the Z80 CPU pins 7 to 15 [1225] Note VA4 boards have resistor pack on Z80 data area marked as RA1; VA3 boards have it as a bodge Note clearance and general sizing of reset switch; this changes the original reset switch size from 10mm to 8mm [1226] Change original reset switch size back to 10mm from 8mm, but clarifies component measurement and button measurement Change notes regarding the larger 12mm x 12mm switches; consolidates notes 1 and 2 to one note [1227] VA6.8 uses a surface mount version of the Sony CXA1145 video decoder; reflected in replacement section and socket mod section 2020 [0105] Note resistor bodge on the bottom of a model 1 Sega Genesis VA6.x motherboard on RF. MOD case area [0606] Typo fix on Z80 2019/12/06 notes Formatting fix on Main CPU Note 2 [0702] Added VRAM chips to newly created Alternates subsection of Video RAM [0713] Added MC3403 to Replacements section of Sound -> Headphone Amp [0716] Formatting Fix on Capacitor Info List [0717] Removed CXA1634 from Replacement Headphone Amp List, but references to its datasheet apply to CXA1034 as well [0731] Clarify note regarding the resistor bodge connected to RF module pin 2 and FB13 Jalco MGB3-VU3401 RF module added to OEM list as it was shown that earlier units have used them, as well as the later SMS units Specify linear voltage regulators as 78S05 5V 2A regulators Note DC-DC regulators may cause instability with the Genesis when installed [0803] Specify M68K, Z80, and Video RAM's technology manufacturing process (e.g. NMOS, CMOS) Fixed long unnoticed typo in Sound RAM list: Samsung KM62464BL-10 -> Samsung KM6264BL-10 Fixed long unnoticed typos in Main RAM list: Hitachi HM652568LSP-[10, 12] -> Hitachi HM65256BLSP-[10, 12] Change Motorola and Hitachi 68K HC CPUs from CMOS to HCMOS as proper designation Removed JPN from VA1 on C67 in Capacitor List BOM as all VA1 boards are of Japanese consoles 2021 [0324] Fix capitalization in Title (consistency purposes) General formatting changes to Document Update List Fix typo in 2020/08/03 Update List, Line 1 Add Nichicon UPW, URS, ULD, UVR series next to PW, RS, LD, VR series in Nichicon Series Replacements List, as they are alternate names to the same series Fix Nichicon [U]PW, [U]RS, [U]VR series capacitors list, as 1uf 50V caps do not exist for these series [0325] Clarify BOT location in Capacitor List and Capacitor List BOM Add different C1 designation in Capacitor List BOM; for VA0 clock fix board, PCB 839-0231 Change JP1 to JPx in Capacitor List BOM Update JPx in Capacitor List BOM; this now includes VA0 and VA1 revision boards Add Note to Capacitor Info section; notes voltage variations when replacing capacitors on Genesis PCB Add Rubycon YXJ and Chemi-con SMG series to Capacitor Replacements List [0326] Fix typo in 2021/03/24 Update List, Line 4 Change Nichicon predecessors to Nichicon series names in 2021/03/24 Update List, Line 4 Add Genesis cartridge connector, 64-pin (PCB labeled as CN3) to the Serviceable Generic Components List (This oversight was egregious!) Fixes for C79, C84, C111, C112, and C1 (PCB 839-0231) - Specifies which revision had which capacitor; necessitated expanding the entire layout for the Capacitor List to compensate Overhaul of Capacitor Quantity List and Capacitor Part Number List as there were other discrepancies listed there and cap numbers not present (This fixes the discrepancy noted in mid-December) Fixed formatting oversight between Capacitor Quantity List and Capacitor Part Number List [0328] Fixed discrepancy on Capacitor Quantity count re: 10uf 16V caps - there are 11 caps on VA0/VA1/VA2/VA3 boards rather than 12 and 12 caps on VA4/VA5/VA6.x boards rather than 13 Specify which boards had quantity of caps on 100uf 10V caps [0330] Capacitor section now has a Logic Type list; temporarily separate from cap value list and is only for VA6.x boards right now Capacitor section List Types are specified now [0425] Capacitor section 10uf 16V quantity was off by one, now confirmed and fixed (quite confusing, as noted throughout the changelog history... so 2021/03/28 changelog point 1 was incorrect) [1028] Corrected PSG IC on Non-Serviceable Components Specify which Sega ASIC the PSG is integrated with Going from memory on some Sega Genesis Model 1 replacement parts (also general documentation of specs of even non-serviceable components): Serviceable Specific Components CPU: Main: 68000 8MHz [Variations: Signetics SCN68000C8x (NMOS), Motorola MC68000x8 (HMOS), Hitachi HD68HC000x8 (HCMOS)] [Alternates: Motorola MC68HC000x8 (HCMOS), Hitachi HD68000x8 (HMOS), SGS-Thomson TS68000CP8 (HMOS), Toshiba TMP68000P-8 (NMOS)] Note 1: A 220 ohm resistor on CPU pin 6 is required for all HMOS/NMOS CPUs on VA6.x revision boards that use the Sega 315-5313A and Sega 315-5313A-01 VDP ASICs due to a Yamaha 7101 redesign that introduced an errata that causes crashes on these CPUs. (This does NOT apply to VA6 revision boards as it uses the Sega 315-5313 VDP ASIC which does not have the issue.) All CMOS CPUs do not need this resistor. Note 2: The trace near non-populated R68 is usually cut on some VA6.x boards that use CMOS CPUs, however. To clarify, it seems to make no obvious difference with non-CMOS CPUs regardless even when the trace is whole on VA6.x revision boards and may be preemptive for them, but the trace cutting for CMOS CPUs and grounding bodge to PCB on CPU pin 16 are pretty much required on pre-VA6/VA6.x revision boards starting at VA4. Note 3: Alternate location of the 220 ohm resistor is located directly on the CPU of pins 6 (AS) and 16 (GND), negating the need to use the empty R68 area on the bottom of the board in later Model 1 units. Which revision had this resistor located there is unknown at this time. Note 4: Marked on PCB as IC1 Main RAM: 64KB PSRAM [Variations: 2x Hitachi HM65256BLSP-12 (32Kx8 PSRAM, 120 ns, CMOS), 2x Hitachi HM65256BLSP-10 (32Kx8 PSRAM, 100 ns, CMOS), 2x Toshiba TC51832SP-12 (32Kx8 PSRAM, 120ns, CMOS), 2x Toshiba TC51832SPL-10 (32Kx8 PSRAM, 100ns, CMOS)] Replacement: general 120ns or faster PSRAM Notes: Marked on PCB as IC2 (first bank) and IC3 (second bank) Sound: Z80 4MHz [Variations: Zilog Z0840004x, NEC D780C-1] Note 1: Resistor pack, marked 4K7 (4.7k ohms) on pins 7 to 15, probably either an attempt to clean noise on Z80 or fix stability re: sound behavior on VA3 and VA4 board revisions. They are installed as a bodge on VA3 boards, but on VA4 USA/JPN boards, however, this component is marked as RA1 in that same area. VA5/VA6 boards have a 4.7k ohm resistor installed only on D0 (pin 7) on the bottom of the board near YM2612 D0 (pin 2), so it was fixed on this revision set. Note 2: Marked on PCB as IC6 Sound RAM: 8KB SRAM [Variations: Sanyo LC3664AL-10 (8Kx8 SRAM, 100 ns, CMOS), Sanyo LC3664R L12 (8Kx8 SRAM, 120 ns, CMOS), Fujitsu MB8464A-10 (8Kx8 SRAM, 100 ns, CMOS), NEC D4168C-15-SG (8Kx8 XRAM, 150ns, NMOS), NEC D4168C-10-SG (8Kx8 XRAM, 100ns, NMOS), Fujitsu MB8464A-10LL-SK (8Kx8 PSRAM, 100ns, CMOS), Sony CXK5864CP-70LL (8Kx8 SRAM, 70ns, CMOS), Samsung KM6264BL-10 (8Kx8 SRAM, 100ns, CMOS)] Replacement: general 150ns or faster SRAM or PSRAM Notes: Marked on PCB as IC7 -- Sound: FM Synthesizer: Yamaha YM2612 Notes: Marked on PCB as IC11 Headphone Amp: Sony CXA1034P (A1034) Replacement: Sony CXA1034P, Panasonic AN7108, Major Brands MC3403 Note 1: Refer to CXA1634 for notes re: CXA1034; as CXA1634 is bass boost version of this chip Note 2: Marked on PCB as IC12 Dual Opamp Amplifier: LM358 [Variations: TI LM358P, ST LM358N] [Alternates: TI LM358N] Replacement: one that matches/near matches TI or ST IC specs Notes: Marked on PCB as IC14 -- Video: Encoder: Sony CXA1145 [Alternates: Itri Erso ES71145(S)] Note 1: All model 1 units before VA6.8 use a through-hole design. From VA6.8 on, it uses a surface mount design. Note 2: Marked on PCB as IC13 RAM: 64KB VRAM [Variations: 2x Hitachi HM53461ZP-12SG (64Kx4 VRAM, 120ns, CMOS), 2x Samsung KM424C64Z-10 (64Kx4 VRAM, 100ns, CMOS), 2x NEC D41264V-12 (64Kx4 VRAM, 120ns, NMOS), 2x Fujitsu MB81461-12 (64Kx4 VRAM, 120ns, NMOS)] [Alternates: 2x Mitsubishi M5M4C264AL-12 (64Kx4 VRAM, 120ns, CMOS), 2x Hitachi HM53461ZP-10 (64Kx4 VRAM, 100ns, CMOS), 2x Vitelic V53C261Z10 (64Kx4 VRAM, 100ns, CMOS)] Replacement: 120ns or faster VRAM Notes: Marked on PCB as IC9 (first bank) and IC10 (second bank) -- Power Connector PCB Notes: Marked on PCB as CN11 --- Non-Serviceable Components Sound: PSG: TI SN76489/SN76496 clone (within Sega VDP ASIC) [this is unofficially called the Sega PSG; their PSG behavior is slightly different from the original PSG in square wave stage count (16-bit shift register on the Sega PSG vs 15-bit shift register in the original IC) and noise feedback generation] -- Video: Main: Sega VDP (Yamaha YM7101) [Variations: 315-5313 (VA6), 315-5313A (VA6.5), 315-5313A-01 (VA6.5/VA6.8)] Notes: Marked on PCB as IC8 -- I/O: Main: Sega I/O 315-5433 (VA6.x) Notes: Marked on PCB as IC4 --- Serviceable Generic Components Adapter: Model 1602 series adapter [Center pin is negative! Just a warning.] Specs: linear (unregulated?) 9V or 10V DC, 1.2A (1200mA), usual 2.1mm x 5.5mm barrel connector, negative polarity ( + --C-- - ) Replacement: a known good, great quality, and very reliable switching adapter that is 9V, 1.2A minimum, and negative polarity (center pin = negative); it's 2019 after all. Also, do NOT cheapen out on the supply. Like PC power supplies, things never go right with a bad cheap supply, especially with noise on the video and audio outputs, heat issues (depending on voltage amd amperage rating), and even general instability. -- Variable resistor (slide potentiometer): Unknown Replacement: one taken from an old Sega Mega Drive/Genesis Model 1 unit for now [something I will look into at some point] Notes: Marked on PCB as VR1 -- Power switch: On-On type, 0.25-inch tall square slide switch, rating should be at least 10V, 300mAh [?] Notes: Marked on PCB as SW1 -- Reset switch button: through-hole soft rubber tactile, 10mm x 10mm component size, 8mm diameter button size, 4mm height, SPST-NO type Replacement: through-hole tactile, 10mm x 10mm component size, 4mm height, SPST-NO type (unless you really want another soft rubber tactile switch) Note 1: 12mm x 12mm component size, 10mm diameter button size do fit, but assume 2mm additional square diameter for units that measure the button size but not the component size (very rare). You will have to bend the pins a bit inward due to the additional 2mm size, otherwise it will not fit in the through-hole area. This affects the clearance of the headphone jack PCB; it is a bit tight on the right side because it is located quite close to the switch in that area in general (headphone jack PCB will still fit without any modification to itself or the larger switch). Note 2: Marked on PCB as SW2 -- Controller connectors: 2x single black plastic DE-9 9-pin right-angle male receptacles Notes: Marked on PCB as CN5 (first controller port) and CN6 (second controller port) -- AV connector: DIN 8 262-degree (also called DIN8U) [You can also replace it with a DIN 8 270-degree (DIN8C) connector but you will no longer be able to use the official SEGA RGB cable with your unit.] Notes: Marked on PCB as CN1 -- Cartridge connector: 64-pin (32x2) card edge connector, flanged, with mounting holes, 2.54mm pitch Replacement: One from a broken Sega Genesis console or one from the Internet Notes: Marked on PCB as CN3 -- RF Modulator: Generic (does have pinouts for a short version and long version), Jalco MGB3-VU3401 (earlier Mega Drive/Genesis units), Mistumi MDG-VA3424 (later Mega Drive/Genesis units) Replacement: Jalco MGB3-VU3401, Mitsumi MDG-VA3424 Note 1: There is a 1/2W 100 ohm 5% tolerance resistor bodge from the factory soldered on the bottom of the Sega Genesis VA6.x motherboard connecting from the RF modulator's case (which is already grounded, note) to the far end of the FB13 component, which is a ferrite bead. In the schematic, FB13 is attached to the Video pinout (pin 2) of the RF module. Note 2: Marked on PCB as RF. MOD -- Crystal Oscillator: NTSC: 53.693 -> 53.6931 -> 53.693175 MHz PAL: 53.203 -> 53.20342 -> 53.203424 MHz Note: These are tight fits. Replacements: NTSC crystal range (MHz): 53.693 or tighter, 25ppm or lower recommended PAL crystal range (MHz): 53.203 or tighter, 25ppm or lower recommended General Notes: 53.693175 MHz - NTSC (x15) 53.203424 MHz - PAL (x12) Marked on PCB as OSC1 -- Voltage Regulators: 2x Motorola 7805CT 5V TO-220-3 Positive Polarity Replacements: 2x 78S05 5V 2A TO-220-3 pin positive polarity regulators as the original 1A units seem inadequate in the design nowadays (never mind the age of them). Buck converters/DC-DC converters (i.e. 7805-SR) can be used, but good ones are more expensive. However, they are much more efficient, so you can forgo the heatsink. Though, these units are sensitive to DC-DC regulators (usually instability in the system when used), so you are more likely to use the 78S05s instead. Notes: Marked on PCB as IC15 (first 7805) and IC17 (second 7805) -- Capacitor Info (applies to all Model 1 Genesis units) This is preliminary info regarding capacitors belonging in Model 1 Sega Genesis areas. This will have to be revisited for power areas, video areas, audio areas, and general logic areas. Note: VA3 boards can use the original lower voltage value capacitors in their place as marked in the list (10uf 25V to 16V; 47uf 16V to 10V), especially if the originals were Taicon and Chhsi; any other revision can use the higher voltage value capacitors in their place if desired. The designs between PCB revisions are pretty much the same. Capacitor Quantity 220uf 16V 1 100uf 10V * (7 on VA0/VA1/VA2/VA3/VA4 boards, 8 on VA5/VA6.x boards) 10uf 10V/16V/25V * (12 on VA0/VA1/VA2/VA3 boards, 13 on VA4/VA5/VA6.x boards - see Part Number List for matching specs) 220uf 10V 3 1uf 50V 6 47uf 10V/16V * (9 on VA0 boards, 8 on VA1/VA2/VA3/VA4 boards, 7 on VA5/VA6.x boards - see Part Number List for matching specs) 100uf 16V 1 220uf 6.3V 1 (for VA3 boards, used as bodge on bottom of PCB near VRAM pin 18 - VCC and ground) Capacitor Value List Part Number Rating C1 220uf 16V C4 100uf 10V C5 10uf 16V (16V or 25V on VA3) C6 (VA0) 47uf 10V C13 10uf 16V (16V or 25V on VA3) C23 (VA1/VA2/VA3/VA4/VA5/VA6.x) 100uf 10V C24 100uf 10V C30 10uf 16V (16V or 25V on VA3) C31 10uf 16V (16V or 25V on VA3) C32 220uf 10V C38 10uf 16V (16V or 25V on VA3) C40 1uf 50V C41 10uf 16V (10V on VA0/VA1/VA2, 25V on VA3) C42 1uf 50V C43 10uf 16V (16V or 25V on VA3) C44 1uf 50V C49 100uf 10V C50 220uf 10V C51 220uf 10V C52 100uf 10V C53 100uf 10V C55 10uf 16V (16V or 25V on VA3) C57 10uf 16V (16V or 25V on VA3) C58 1uf 50V C59 47uf 10V (16V on VA3) C60 47uf 10V (16V on VA3) C61 1uf 50V C62 1uf 50V C63 47uf 10V (16V on VA3) C64 10uf 16V (25V on VA3) C65 47uf 10V (16V on VA3) C66 47uf 10V (16V on VA3) C67 (VA1/VA2/VA3/VA4) 47uf 10V (16V on VA3) C68 47uf 10V (16V on VA3) C71 10uf 16V (25V on VA3) C72 10uf 16V (25V on VA3) C74 100uf 10V C79 (VA1/VA2/VA3/VA4/VA5/VA6.x) 100uf 16V C86 (VA2/VA3/VA4/VA5/VA6.x) 100uf 10V C111 (VA5/VA6.x) 47uf 10V C112 (VA5/VA6.x) 10uf 16V JPx (VA0/VA1/VA2/VA3/VA4) 47uf 10V (16V on VA1 and VA3 boards) C1 (PCB 839-0231, VA0) 47uf 10V (This is on the VDP clock fix board!) BOT (VA3) 220uf 6.3V (present on VA3 boards only so far, located on bottom side of board near VRAM pin 18 - VCC and ground) Capacitor Logic Type List Part Number [VA6.x ONLY; separate for now] Logic Type C1 Power C4 Power C5 Power C13 Power C23 Power C24 Power C30 Audio C31 Audio C32 Video C38 Power C40 Audio C41 Audio C42 Audio C43 Audio C44 Audio C49 Power C50 Audio C51 Audio C52 Power C53 Audio C55 Audio C57 Audio C58 Audio C59 Power C60 Power C61 Audio C62 Audio C63 Power C64 Power C65 Power C66 Power C68 Power C71 Power C72 Power C74 Power C79 Power C86 Video C111 Power C112 Power Rubycon Series Direct Replacement: TWSS (CE W/SSA code replacement; no 47uf 10V and 10uf 16V caps; discontinued, but NOS is still floating about) Rubycon Series Indirect Replacements: YXF (except 47uf 10V and 10uf 16V caps) YXJ (long life; except 47uf 10V and 10uf 16V caps) YK (discontinued; except 47uf 10V and 10uf 16V caps) PK (YK replacement as of December 2019; except 47uf 10V and 10uf 16V caps; recommended!) Panasonic Series Replacements: FC (except 47uf 10V and 10uf 16V caps) Nichicon Series Replacements: PW, UPW (except 1uf 50V) RS, URS (low profile; except 1uf 50V) LD, ULD (accidental find; long life; except 47uf 10V, 10uf 16V, and 220uf 6.3V caps) VR, UVR (except 1uf 50V) Nippon Chemi-Con Replacements: LXZ (except 47uf 10V and 10uf 16V caps) SMG (SME replacement as of March 2021; except for 47uf 10V, 47uf 16V, 10uf 16V, and 100uf 10V caps; recommended!) -- Diode list D1, D3 - 1N4002 100V 1A general purpose recovery rectifier D2 - 1S2473 40V 11A fast recovery rectifier [Apparently replaceable with a 1N914 or even a common 1N4148 zener diode] -- Proposed IC Socket List (for VA6/VA6.x board revisions only as of now) Sockets can either be dual-wipe or machine tooled. DIP 1x DIP-8 (300mil/0.3in/7.62mm spacing) [for LM358] 1x DIP-16 (300mil/0.3in/7.62mm spacing) [for CXA1034] 1x DIP-24 (400mil/0.4in/10.16mm spacing) [for CXA1145P, not applicable to VA6.8 boards as this component is a surface mount design] 1x DIP-24 (600mil/0.6in/15.24mm spacing) [for YM2612] 2x DIP-28 (300mil/0.3in/7.62mm spacing) [for Main PSRAM] 1x DIP-28 (600mil/0.6in/15.24mm spacing) [for Sound SRAM] 1x DIP-40 (600mil/0.6in/15.24mm spacing) [for Sound (Z80) CPU] 1x DIP-64 (900mil/0.9in/22.86mm spacing) [for Main (68000) CPU] ZIP 4x SIP-12 [for VDP ZIP RAM] or 8x SIP-6 [for VDP ZIP RAM]