IGS PGM2¶
The follow-up to the PGM (2007), and a preservation case still open: each game's processor holds its own internal ROM, different from title to title. Until those chips are extracted, the games concerned do not exist in the archive.
Identification¶
| Field | Value |
|---|---|
| Manufacturer | IGS (Taiwan / China) |
| Years | 2007 onwards |
| CPU | IGS036 — ARM (ARMv5T, probably ARM9) core, with internal ROM |
| Graphics | IGS037 |
| Sound | YMZ774-S |
| Auxiliary MCU | R5F21256SN — IC-card communication, called MPU by the games |
| Memory | IS61LV25616AL (SRAM) |
| Architecture | bare motherboard + cartridge |
| PCB format | IGS proprietary |
The motherboard holds no ROM at all
That is the platform's structure: the motherboard is bare bones, with no ROMs whatsoever. Everything is in the cartridge — the IGS036, the data ROMs, and on some games Flash and SRAM as well.
A motherboard alone is therefore worth nothing without a cartridge, and the other way round.
⚠️ The preservation gap: undumped IGS036s¶
This is the subject of the page.
Each game has its own internal ROM, and not all are dumped
The IGS036 is an ARM CPU with internal ROM — like the IGS027A on the original PGM. And that internal ROM differs from game to game: it carries title-specific code.
The MAME driver puts it plainly in its outstanding work: “Support remaining games (need IGS036 dumps)”. In other words, several PGM2 games are not preserved, for want of being able to read their processor.
The direct consequence: a PGM2 cartridge of an undumped game is potentially the only copy of that code. Treat it as such.
The holographic stickers
MAME records that the IGS036s carry holographic stickers with a printed number whose relationship to the game is not established. It is a useful physical identifier to photograph, but nothing is inferred from it.
Cartridges that are not alike¶
Depending on the game, the cartridge holds:
- the IGS036 and the data ROMs — the general case;
- Flash + SRAM in the ROM socket, on some titles;
- a dedicated program ROM module, on Knights of Valour 3 only.
→ What holds for one cartridge therefore does not necessarily hold for the next.
Notable games¶
Oriental Legend 2 (2007, several revisions and Chinese versions) · Knights of Valour 3.
Common faults¶
| Symptom | Probable cause | Next step |
|---|---|---|
| Motherboard alone, nothing boots | normal — it holds no ROM | The cartridge is required |
| Will not boot with the cartridge | cartridge contacts, or the IGS036 | Clean the contacts with isopropyl alcohol |
| No sound | YMZ774-S | Independent stage |
| IC-card reading fails | R5F21256SN (the “MPU”) | MCU dedicated to that function |
| Corrupt graphics | IGS037 or the SRAM | Diagnose by comparison — no replacement chips |
Repair (technician)¶
- Never bin a cartridge, even a dead one: it may hold a never-extracted IGS036. See the box.
- Two separate items: the motherboard and the cartridge fail independently. Trying the cartridge on another motherboard settles it quickly.
- No IGS chip has a replacement: the IGS036 and IGS037 are diagnosed by comparison.
→ Methods: PCB diagnosis · Recap
Procedure — a dead board, step by step ✅¶
What this adds
The general method lives in PCB diagnosis. This is its application to this platform: the same order, but with the values actually expected here, so you do not have to go back and forth.
Tools: multimeter, oscilloscope (or frequency counter), current-limited bench supply, desoldering braid. → Tooling
If the board is still in a cabinet
A CRT holds its charge with the machine unplugged. → CRT safety
1. Inspection, power off. Corrosion, cut tracks, oxidised EPROM legs, leaking SMD capacitors, dubious earlier repairs.
2. The connector, before anything else. A large share of "dead boards" are a contact problem, not a fault. Clean the contacts with isopropyl alcohol and reseat — not with an abrasive eraser on a gold edge, which takes the plating off and brings the problem back worse. It costs two minutes and settles the question.
3. Power, measured on the board. Aim for +5.0 V measured as close as possible to where power reaches the board — not at the PSU output: the drop is in the loom, and that is exactly what makes a board boot on the bench and not in the cabinet. Where you probe depends on this board's connector — JAMMA edge, JVS loom or a proprietary harness — plenty of makers kept one long after JAMMA arrived — see Identification above. → Wiring Check −5 V and +12 V too if the sound stage uses them. Suspected short: bring it up current-limited and find the hot spot.
4. /RESET. It must release after power-up. Held low = the CPU never starts. A 1–2 Hz loop is not the reset circuit, it is the watchdog: the CPU is crashing at boot, so look at the bus, not at the reset.
5. Clocks. There is no measurement table for this platform — MAME's sources yield nothing usable for it. Any frequency quoted under Architecture on this page serves as a marker; otherwise compare against a working board rather than against a number: an invented value condemns healthy parts. → PCB diagnosis
6. Bus. Activity on the main CPU's address lines tells you whether it is running or frozen. Frozen with good clocks and good reset → work RAM, bus buffers, ROMs.
7. It boots but the picture or the sound is wrong — that is another job: see Common faults on this page, then signal tracing.
Modernisation & mods¶
- ⚠️ Do not host ROMs or IGS036 dumps — method only.
- Neighbours: see the original PGM, whose IGS027A poses the same kind of problem.
Emulation & FPGA¶
MAME covers the platform (igs/pgm2.cpp, driver by David Haywood, Xing Xing and
Andreas Naive). Decryption is correct in most cases according to the driver —
but the remaining obstacle is not the encryption: it is the missing IGS036
dumps.
Photos / assets¶
(To take: the bare motherboard, an opened cartridge with its IGS036, and the chip's holographic sticker — the detail nobody photographs.)
Sources & attribution¶
Text (synthesised here; sources listed for attribution):
- MAME —
src/mame/igs/pgm2.cpp(BSD-3-Clause / GPL, driver by David Haywood, Xing Xing and Andreas Naive): the bare motherboard with no ROMs at all, the IGS036 (ARMv5T CPU with internal ROM differing per game), IGS037 (graphics), YMZ774-S (sound), R5F21256SN (IC-card MCU, called MPU by the games), IS61LV25616AL SRAM; the cartridge variants (Flash + SRAM in the socket on some titles, a dedicated program ROM module for Knights of Valour 3); the outstanding task “Support remaining games (need IGS036 dumps)”; and the note about the IGS036s' holographic stickers whose number does not appear tied to the game — https://github.com/mamedev/mame/blob/master/src/mame/igs/pgm2.cpp
Review & corrections
How this space is used
Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.
Reading is open to everyone; posting requires signing in with Discord. Reports from the wiki's declared reviewers are handled first; anyone else's are read too, but go through a human before anything is changed.