What's inside (and outside) the Atari Falcon?

It took me 30 years to upgrade from my Atari #Mega-STE to a Falcon! But last week I had an opportunity to finally get one at a reasonable price (even if it means I have to fix a few things…)

This is what it looks like:

It’s got a German keyboard but, as we’ll see later the casing and the motherboard are UK… and the TOS inside is US ;)

This machine definitely has had a long life before reaching me, and it’s probably an assembly of 2 or 3 original computers…

Ports

Let’s have a quick look at the ports.

First, the mouse and standard joystick ports are still under the keyboard, hard to access, as in previous ST computers.

Then, the backside:

From left to right:

DSP port: DB26 female port. This is new on the Falcon (compared to previous #Atari ST/TT computers). Contrary to the other ports, the pinout is not documented in the user manual. However, the manual mentions that it “allows easy connection of low-cost 19.2K baud fax/data modems, voice-mail systems, direct-to-disk digital audio recorders, JPEG/MPEG image compression, etc.”
Headphone jack: Stereo 3.5mm
Microphone jack: Stereo 3.5mm
SCSI II 50-pin female connector
Monitor connector: proprietary D19 connector that Atari introduced on the Falcon. Nothing standard can connect to this. You need to buy (or make) and adapter for:
1. either a low res RGB TV/Monitor like on STs,
2. or a B&W “Hi res” monitor also like on STs,
3. or more interestingly: a VGA monitor
A “Television” RCA composite output. I think this port is odd:
- It’s basically bad quality and was already outdated at the time the Falcon came out
- It should be Yellow like all other composite signal connectors in the world :p
A DB25 Female parallel port marked “Printer” but it’s actually bidirectional so it could also be used by scanners or other input devices.
A DB9 Male Serial port called “Modem” but it’s a standard #RS-232 port that can be used for all kinds of Serial devices (in/out)
A port marked “LAN” (8-pin Mini DIN Female) which is compatible with AppleTalk but even more interestingly, the user manual calls it “SCC Connector” and seems to imply that it is compatible with #RS-422 and RS-423.
A standard power connector
A reset push button

Then, on the Left side:

MIDI Out/Thru and MIDI In ports: DIN 5 Female connectors
Cartridge port (cartridges can attach 128 KBytes of ROM to the system)
Enhanced Joystick ports: these are new on the Falcon and would allow to connect analog joysticks (I am not sure any games ever took avantage of that)

Finally the right side:

The only standard equipment on this side is the floppy disk drive ( #FDD ), which is a standard High Density 1.44 MB dive. Interestingly, Atari no longer used a special shape for the eject button on the Falcon and just went with a standard rectangular cutout that could accommodate any standard FDD facade.
The other connector you see is a mod in inherited from a previous owner, it allows to connect an external Atari keyboard. I tried it with my Mega STE keyboard and it worked fine. The connector was glued inside the box which made it flush with the outside. It looked nice but made it a huge pain to open the case. So for now I got it “out of the way” like this.
- The red switch is for selecting between internal and external keyboard.
- All in all this mod is a nice addition if I don’t want to use a German keyboard.

Disassembling

There are more screws than on STs and some of them now use metallic inserts which makes them much nicer to remove and put back multiple times.

The first thing we see when we remove the cover and the internal keyboard (TODO: add photo with keyboard ;) is the internal RF shielding:

We also see the internal speaker which is of poor quality but probably deemed useful for users who would connect to a VGA Monitor which typically has no sound (contrary to TVs or previous low res monitors).

Once we remove the shielding we see a bit of the motherboard but it’s covered with the power supply and the Floppy Disk Drive:

We also see the RAM module which could be easily replaced at this stage. In this case it’s a 4 MB module. It seems the same board was also used for 1 MB modules.

I know the Falcon could also support 14 MB RAM modules but I have never seen an original one from Atari.

The power supply looks more robust than the ones found on STs. Maybe the board color alone, which is not brown, plays a big role in conveying a higher quality impression ;)

After removing the power supply and the FDD:

I believe the empty socket under the power supply is for an optional Motorola 68881/2 arithmetic coprocessor.

The FDD is an Epson SMD-300:

Pin 1 (the red marking on the ribbon cable) is on the left.

There is no sticker to explain all the jumpers. Here is a datasheet for the SMD-340 which is probably close enough for future reference.

Next we can take out the whole motherboard and shielding assembly:

Here I have removed the RAM module and we can see the TOS ROM underneath (512 KB).

And remove the top shielding completely:

This reveals the very noisy fan. It’s unclear what it is supposed to cool and how the air flow has been designed. The main processor sits far away under the power supply. It’s very difficult to see how the fan will cool the processor and the power supply…

What’s on the board

CPU: Motorola 68030 operating at 16 MHz
FPU: Socket for an optional Motorola 68881/2
BUS: The Atari manual says “32 bit data and 32 bit address” but I believe in reality the data bus is still 16-bits, just as on the ST. Only the Atari TT or accelerator cards like the CT60/CT63 have a true 32 bit data bus…
DSP: Motorola 56001 operating at 32 MHz
Processor expansion headers that the manual describes as “Internal direct processor slot for 386SX PC emulation, DMA coprocessors, etc. "
Blitter
Real Time Clock and NVRAM Chip: ST MK48T87B-24 “Timekeeper™ RAM” (equivalent to Dallas DS1287 or DS12887 which is more recent)

The extra chip and wires at the bottom (on U63) is an official Atari modification for fixing a “hardware bug” on the clock line that is distributed to the various parts of the system.

The bottom shielding can then also be removed: