This is weird.
NES Demo Unit
The following is an email I received from a
contributor, and, with his permission, am putting up the info
here. I apologize for not having a picture of the unit, I know
what the unit looks like, but I have been unable to find one
floating around; I know all text is a bit lame, especially
because this unit is pretty cool looking. Oh, well. If you can
help out with some info on this unit, please pass it onto me and
I will forward it to him (he wishes to remain anonymous). Thanks.
A couple of weeks ago I received a Nintendo "M82 GAME SELECTABLE WORKING
This would have been installed in shops selling NES games, to allow multiple
games to be demonstrated and played. It is different to the one illustrated
on tsr's NES Archive.
It is a desktop PC-sized unit, with a sloping portion at the front with
recesses for two controllers. The case (except the front panel) is metal,
and is designed to support the weight of a TV or monitor. There is a
"holster" on the side, for resting the Zapper. The two controllers plus the
Zapper are connected in such a way that to remove them requires opening the
front panel of the unit. There are two additional controller ports inside. I
don't know what these are for.
There are 12 NES cart slots, arranged in three columns of four. The game
name on the edge of each cart is visible though a window in the front panel.
There is a button that the player can press to cycle between games.
The unit is directly mains powered. On the rear panel there are A/V and RF
outputs, and a rotary switch to set the timeout value. This allows play time
to be limited to 30 seconds, 3 minutes, 6 minutes or 128 minutes. After this
time the unit resets.
When first powered on, there is an intro sequence. On the background of a 3D
starfield effect, the letters of the Nintendo logo appear one by one, and
then the words ENTERTAINMENT and SYSTEM scroll in from the left and right
below this. Then brief instructions for use are displayed. Background music
If left alone, the unit shows this intro sequence and then activates the
first game cartridge for a couple of minutes. It resets back to the intro,
then goes onto the next game and so on.
I tested the unit with the seven or so European games that I have, and it
seems to work okay. However, for some reason IRQs (as many MMC3 games use)
do not seem to be supported. Either this is a fault in the unit or a design
problem. I will investigate this. This causes graphical corruption (e.g.
text shown with the wrong bank), and makes some games impossible to play
(e.g. Shatterhand, Star Wars).
A black plastic cover on the rear covers a NES expansion port, as found on
the underside of a normal NES.
It came with a rather minimal service manual, which basically describes
how to change the controllers and power supply board. There was no
Other hardware information
The CPU, PPU and CIC are socketed, which would allow easy conversion to
NTSC format. However the crystal is not, and this would have to be
desoldered. Now I just need to find a source for an NTSC CPU, PPU, crystal
The modulator section is identical to that of a (European) NES. Two cables
lead from the A/V sockets to the sockets on the rear panel. There is no
voltage regulator and heatsink attached to the modulator casing. This
function is provided by the power supply board. The modulator section is
bolted to the casing, and is easily removable.
There is a jumper wire on the power supply board which can be moved to
select between 220V and 110V operation.
Next to the connector on the PCB which leads to the time selection switch is
what may be solderable jumper pads. Maybe bridging these disables the
The unit works with no cartridge inserted, and the intro is visible. This
implies that there is some kind of lockout-satisfying hardware inside, or
that the CIC reset signal is switchable in software (probably done by the
microcontroller). There is only one CIC inside the unit, a 3195A European
The service manual mentions a 68hc05c4 microcontroller. This is not marked
as such, but instead has this text printed on it:
(C) (M) 1987
Z IRS1 (or maybe IRSI)
Perhaps the 6805 handles game selection and whether the CIC is active. It
apparently has 4Kb of mask ROM inside. This internal ROM may or may not be
readable from the outside (by using a suitable programmer).
Main PCB size is about 190x450mm. Three 72-pin male edge connectors on the
front edge mate with three edge connectors on the reverse side of the cart
slots board. Silk-screened onto the PCB is this text:
(M) (C) 1987 Nintendo
IRS-45-003 Rev. F
Serial number label says M-000023431 (different to what the serial label on
the rear of the case says).
The startup/intro program is contained on two EPROMs. Label on the AM27C128
next to the CPU says:
Label on AM27C64 next to PPU says:
I hope to be able to dump these to disk eventually.
Latest chip manufacture date is 9031.
There is a small 20-pin socketed IC which has a label on top, on which is
printed "6505". Perhaps this is a Nintendo part number. Maybe this IC is a
PAL or similar.
74-series ICs on the main board:
ALS245 x 7
HCT541 x 8
ALS251 x 4
HCT4514 x 1
HCT373 x 2
HCT540 x 2
HCT139 x 2
HC04 x 2
HCT08 x 2
Silk-screened onto the PCB near the PPU, HCT541 & HC04 it says:
This probably refers to four pins on the HCT541.
That's about all for now. Has anyone ever seen one of these "in the wild"?
Thanks to H. Meun (email@example.com) for all of the scans
Click here to see page one of the manual for this unit (warning:
large 2550x3236 GIF file)
Click here to see page two of the manual for this unit (warning:
large 2550x3236 GIF file)
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