Console modding/repair service – PS1/PS2 modchip install, MegaDrive RGB bypass and more!

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Description

Send me your retro gaming system and I will mod it for you! I can also repair consoles… just describe to me what the problem is (don’t order this product if it’s just a repair. email me and I’ll give you a price quote)

I provide services for PS1, PS1, Master System and MegaDrive I/II. These are the systems that I’m familiar with at present. I may or may not offer services for retro Nintendo stuff in the future.

See the drop down list above, for a list of services that I provide. You can order multiple mods by just adding different variants of this product to your shopping cart.

Some explanations of each mod provided in this collection of services:

PS1 8wire MM3 modchip

This is installed to the drive controller on the PS1 aswell as intercepting a few clock signals. It forces the PS1 to boot all games, even if burned to a CD-R.

Normally, the PS1 checks for a “wobble” in the early sections of the disc. This wobble contains region data and cannot be duplicated on CD burners. If not present, the game will not boot. The modchip intercepts these checks and injects the correct response so that the system will treat your backup CD-R game as an original disc, thus defeating the copy protection.

Originally, modchips sent these signals constantly. Newer games detected modchips and refused to boot. However, these modchips that I install are called stealth modchips because they only operate on bootup or when a new disc is inserted or when the reset button is pressed. This way, games cannot detect a modchip.

PS1 CSYNC on cvbs/luma

Normally, a PS1 outputs Red/Green/Blue but no Composite Sync. The sync signal (combining hsync and vsync) synchronizes the output so that different parts of the image are in the right place. Without a sync signal, there would be no way to get a stable image on the screen.

The PS1 *does* output Composite Sync, but it’s mixed into the Composite Video and Luma channels. Composite Video combines RGB signals, sync, subcarrier and a bunch of other stuff… it’s a very noisy and low quality signal but most TVs/upscalers will extract the sync signal from it anyway.

The Luma channel is part of S-Video and it controls brightness (Chrome controls the colour). The sync signal is mixed into Luma.

RGB with sync on Composite Video more or less defeats the purpose because you still get the interference from the subcarrier signal which will cause a jailbar effect in the video output. You *could* cut the subcarrier trace going to the video encoder…. but there’s no point. Composite Sync (on its own) is superior.

RGB with sync on Luma is a little bit better. You get a lot less interference but it’s still not the best possible signal.

RGB with clean csync is the best quality signal for most consumer TVs/upscalers and it’s also the most compatible (some equipment doesn’t work unless you feed it clean Composite Sync).

*Another* solution is to use a Sync Stripper on the Luma or CVBS channel… but you still get interference.

If you want the best possible picture quality, then you will want this mod to be done.

PS1 GPU outputs TTL sync. I attenuate it using a 470ohm+220uF setup.

PS1 dual PAL/NTSC crystals

I ship PAL PS1s. PAL PS1s when chipped can boot NTSC USA/Japan games but the main 53.2mhz PAL crystal oscillator, while correct for PAL, is also used for NTSC mode, which creates an off-spec vsync speed of about 59.3hz (the correct spec is about 59.9hz or very near it).

Pin 192 and 196 are the PAL and NTSC clock inputs on the PS1 GPU, respectively. I cut the trace leading to pin 196 and connect a 53.69mhz crystal oscillation signal to it. This is correct for NTSC, resulting in perfect NTSC timings.

This mod fixes NTSC game compatibility and also ensures correct function with any TV or upscaler that is NTSC/60hz compatible.

With this mod, Composite Video and S-Video will also now output correctly in colour on NTSC games, because the subcarrier clock is derived from the clock signal going into pin 196 on the GPU (NOTE: on PS1s later than SCPH-5xxx, the oscillator is replaced by a clock generator which generates the subcarrier signal separately so the output will be PAL60 but RGB will still have correct vsync timings at least).

PS1 RGBHV

Pins 158 and 159 on the PS1 are separated hsync+vsync outputs.

RGBHV is uncommon but some PVM CRTs support it. The OSSC (open source scan converter) also supports it.

For this, I cut +5V and cvbs on the multi-out and connect the hsync/vsync signals instead, attenuated (470ohm+220uF each) and I modify an RGB SCART cable (with sync on cvbs) to be a VGA cable instead (it’s not VGA which is 31khz hsync. the hsync will still be about 15khz).

For compatibility with light-gun games (e.g. time crisis) I can also install a break-out RCA jack for composite sync (attenuated 470ohm+220uF). This will enable to play light-gun games on a PVM CRT that takes RGBHV as input.

NOTE: Luma is intentionally left untouched. This means that S-Video output can still be used on the console (it also means that RGB SCART with csync pulled from luma will still work, though in that case you’d need to grab +5v from an external source rather than the PS1’s AV multi-out)

NOTE: If you wish it, I can also install a switch for toggling between +5V or hsync on the +5V pin on the multi-out. By setting it to +5V mode you will again be able to use RGB SCART cables on regular TVs with sync on luma being used…. but be careful! If you plug +5V into the hsync channel on your PVM you will blow up your PVM 😉

PS2 21-wire stealth modchip (modbo4)

PS2 copy protection is a true beast.

The “mechacon” chip in the PS2 acts as a hypervisor aswell as drive controller for the PS2. It checks the book type of the disc being inserted; if anything other than DVD-ROM, the disc is rejected. This alone makes it impossible to make compatible DVD-Rs since they have their book type set to DVD-R.

The same analog wobble is also used like on PS1 but it’s much more complex. Encrypted data is also laced throughout the media being inserted into the drive….

Still, hackers quickly cracked it back in the early 2000s 😉

The modbo4 is a clone of the original Matrix Infinity chip. It intercepts the Mechacon making it also accept discs with DVD-R book type (aswell as CD-R) and injects code into the PS2 BIOS to disable the copy protection.

The result is that you can download games on the internet and burn them straight to DVD then play them. Naughty!

PS2 csync

same as PS1 csync really. Though I don’t offer RGBHV since the PS2 is already VGA capable….

MegaDrive1 RGB bypass

I use voultar’s board for this. It replaces the default video encoder with a much more modern 4-line video driver that just acts as an RGB amp/buffer and it has a neat LPF on it to filter out noise. With this plus a few board tweaks (e.g. cutting subcarrier and re-routing a few signals, lifting the RGB outputs of the VDP out of circuit etc) results in much sharper video output on RGB.

Without this mod, colours on RGB are a bit off and there is a lot of interference causing some visual imperfections in the output. Sega consoles are infamous for this!

I hope to do a YouTube video on this at some point but you can find pics of this elsewhere on minifree.org

THS7374 is the product name of the encoder chip installed by this mod.

NOTE: all other video outputs like RF, CVBS etc are disabled by this mod.

MegaDrive1 M1 Mini Mega

For VA0-VA6 megadrives, the M1 mini Mega replaces the default audio amp, resulting in far superior audio output.

I *cut* mono audio going to the AV multi-out and simply connect the audio output from M1 Mini Mega to the stereo jack at the front of the console. I normally just output it directly to the jack, bypassing the potentiometer used for volume control (in case of noise), but I can connect it to that instead if you wish.

M1 Mini Mega is designed by someone online who goes by the alias FireBrandX

The audio output is at line level but still loud enough for a pair of headphones.

MegaDrive1 10MHz overclock

Pin 15 on the m68k CPU is the clock input, by default it’s about 7.5mhz. I cut the trace going to it and hook the pin up to a switch enabling to select the default 7.5mhz clock or a 10mhz clock. The 10mhz clock is from a crystal that I install.

For switching CPU clock speeds in game, a halt switch is also connected to pin 17 of the CPU. The switch is used to ground pin 17, which sends the CPU into a halt state. Halting the CPU is recommended if switching speeds in-game, then you just un-halt it.

NOTE: some games are unstable with the overclock but it is useful because it can reduce slowdowns in certain games (e.g. sonic when you lose a shitload of rings)

MegaDrive1/2 and Master System 50 60hz and language switch

I install a switch enabling PAL or NTSC mode (50 or 60 hz). I also replace the main crystal oscillator (53.2mhz) with a 53.69mhz one for correct NTSC speeds (I don’t bother with dual oscillotors because PAL games are crap anyway. Most of them are just NTSC games running much much slower, but if you dump the ROMs from PAL cartridges the checksum is often identical to the US/Japan counterpart!)

The vast majority of PAL games run correctly in 60hz, better than in the 50hz mode.

The region switch sets the console in english or japanese mode.

With 60hz+Japanese selected via switch, some games will even change language. For instance, a PAL Streets of Rage II cartridge is the exact same ROM as Bare Knuckle II, the Japanese version and when set this way, that PAL cartridge will morph into Bare Knuckle II 🙂

For Master System 2 I *do* use a dual oscillator setup so that PAL and NTSC games both have correct timings. This is not feasible on MegaDrive consoles due to where the oscillator signals are routed (it would cause a lot of interference).

MegaDrive I/II and Master System 2 capacitor replacement

Electrolytic capacitors fail. That’s simply a reality. Especially old ones.

When they fail, they can leak fluids which corrode the board. If I see this, I make sure to clean up the mess (using IPA, a toothbrush and, where needed, a fiber glass pen). If necessary I also repair traces that have been damaged by leaked electrolytic fluids.

When I’ve determined that the board doesn’t have any damage from corrosion by capacitor fluids, or that I’ve repaired them all, I then install high quality electrolytic capacitors. This vastly increases the lifespan of the console and it’s usually the only thing you need to do when repairing one of these old systems.

As a general rule of thumb, I do this on all of my pre-modded consoles. If you wish it, I can do so on a console that you buy from me.

This only applies to electrolytic capacitors. Ceramic capacitors do not need to be replaced.

Megadrive and Master System exclusively use THT mounted electrolytics, so I use a vacuum solder extractor to cleanly remove the old caps before inserting and soldering the new caps. (if they were surface mount, I’d instead use a hot-air gun to remove them, and either hot air + solder paste or just hand-soldering with iron + hard solder and flux to install the new caps).

MegaDrive2 Triple Bypass

This combines the RGB bypass and Mega Amp 2.0 mod into a single board. The Mega Amp 2.0 is very similar to the M1 Mini Mega.

The benefits are the same as that of separated RGB bypass + M1 Mini Mega on the MegaDrive1 models.

I use the board designed by dbElectronics.

The audio part of the Triple Bypass is designed to drive a pair of headphones.

MegaDrive 1/2 and Master System NTSC conversion

Similar to the 50/60hz service but in this case I hardcode NTSC only. I set the console in 60hz mode and replace the 53.2mhz crystal (for PAL) with a 53.69mhz crystal (for NTSC). I also install a switch for Japanese/English language selection.

Master System 2 RGB DIN slot

Master System 2 only outputs RF by default, which is crap. It’s combined Composite Video and Double Mono. Eww!

I install the DIN with the same pinout as on the Megadrive1, with proper csync. The DIN has separate pins for Composite Video and Composite Sync, so I also route Composite Video with the correct subcarrier signal for PAL or NTSC.

NOTE: If it’s the Sonic model of Master System II, the video encoder doesn’t have a direct composite sync output so I do sync on luma instead. If you wish it, you can use a sync stripper in your scart cable. Sync on Luma is virtually the same as pure Composite Sync in terms of quality and causes very little noise issue.

NOTE: I also do several jailbar fixes. Namely: re-route Z80 clock and colorburst clock signals. Re-route the VDP clock signal. I also cut the RGB traces on the VDP and lift the pins, then re-route RGB directly to the resistor network handling inputs to the encoder. This reduces noise from the board leaking into the cables. I *also* install 4.7uF and 10uF power filter capacitors on *all* 5V inputs to both the VDP and the video encoder. I *also* install a 47uF power filter capacitor on the DIN8 5V pin. All of this substantially reduces noise on the RGB output, leading to virtually non-existent jailbar lines. In my experience, an RGB bypass is not required on a master system 2 console. I even install 4.7uF and 10uF power filter capacitors on the in-line pull-up resistors for the RGB lines coming off of the VDP!

NOTE: I also use a resistor on the subcarrier signal. This reduces the current on the subcarrier signal, for safety reasons. Doing so also reduces jailbars even if using the subcarrier signal. I use the absolute largest resistor while maintaining compatibility with TVs/upscalers.

NOTE: The jailbar fixes also benefit composite video and svideo. If you wish it, I can also install additional break-out connectors for s-video and composite video, with break-out RCA audio connector and 3.5mm jack. This would be useful for Americans who do not have RGB on their TVs. If you wish me to do this, please order this service *twice*.

I also route mono audio to the DIN (its the 8 pin socket) and I install a break-out stereo 3.5mm jack with double mono.

I *also* install an AD828 based op-amp board to drive a headphone output connected directly to the Master System. HOWEVER, there is no volume control. You can buy a cheap audio wire online for your headphones, which will have a volume adjust on it.

MegaDrive1/2 cartslot widened for Japanese games

Japanese and USA/Euro carts have different shapes. Japanese carts won’t fit by default in a European megadrive, so I widen the slot. This makes Japanese carts fit (see pic above for an example. it shows phantasy star II Japanese version slotted into my megadrive)

Additional information

Select mods/repairs

PS1 MM3 8wire modchip, PS1 CSYNC on luma+cvbs, PS1 dual PAL/NTSC crystals, PS1 RGBHV, PS2 21-wire modbo4 modchip +picfix, PS2 CSYNC, MegaDrive1 RGB bypass, MegaDrive1 M1 Mini Mega, MegaDrive1 10mhz overclock, MegaDrive1/2 50/60Hz and region switch, MegaDrive1/2 capacitor replacement, MegaDrive2 Triple Bypass, MegaDrive1/2 NTSC with region switch (no 50/60hz switch) :, Master System 2 RGB DIN slot, Master System 2 PAL/NTSC switch, Master System 2 language switch, Master System 2 NTSC conversion with language switch, Master System 2 capacitor replacement, MegaDrive1/2 cartslot widened for Japanese games

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