check out this wackiness in a removable hard drive sled inside a TASCAM MMR-8: It has a key lock, but the key lock doesn't lock the door, as you'd expect. Instead the lock is just a switch, and it communicates back with some board, which controls a solenoid to unlock the door. Now that's some paranoid over-design!

heh. The manual lists the approved hard drives for use with it.
I guess none of the letters in "SCSI" are "standard"!

also the weird one in that list is the Nikon thing with the asterisk.
It turns out it's a 2.5gb magneto-optical drive that I think was only released in japan?

https://item.rakuten.co.jp/waysas/10015260/?scid=s_kwa_pla_unpaid_211514

Anyway, this is the TASCAM MMR-8.
Sadly it's not as useful (for me) as I was hoping: it has a lot of video support, but it's not really for doing video: it's for syncing audio TO video. This is specifically an audio device, not a video device. Whoops.

fun fact: it turns out that inside it's built on a Socket 7 motherboard. From ASUS!

Also apparently the OS is stored on a Quantum Fireball IDE drive.

So the motherboard is an ASUS TX97. That's based on an Intel 430TX chipset, and can run Pentiums throughs AMD-K6.
It supports up to 256mb of RAM in 168-pin SDRAM slots. 3 ISA slots, 3 PCI slots, and one combination PCI/MediaBus/ISA slot.
Built in IDE, can be powered by AT or ATX power supplies.

And it turns out that CPU is a Pentium 133mhz, SY022.

Let's go through the boards.
The smallest one is this MMR Biphase Option (BOB), ASSY 70303.
Seems to have a bunch of RJ-?? plugs.

Then a Symbios SYM8600SP SCSI board. Seems to be pretty standard, this is probably just an off the shelf component.

The first big custom board is this TimeLine Sync2 ASSY 70386.
A bunch of FPGA chips, custom ASICs, and EEPROMs.
It's 16-bit ISA, but it seems to talk to other boards through that big locking IDC connector on the top left, so that probably doesn't matter much.

Then the MMR UIB, ASSY 70302.
More FPGAs, ASICs, and EEPROMs.
They integrated the serial port from the motherboard into this card, it seems.

Then the 70384 DIO.
Digital I/O, I suspect.

It's got 4 of these CS8411-CS digital audio receivers, and then 4 of these CS8401-CS digital audio transmitters.

And four of these IDT7132SA20J 2 kilobyte dual-ported static-ram chips. Probably for audio buffering/processing at super-low latency

Then another of the same board, but this one is missing the receiver/transmitter chips. It's just got the RAM and FPGA.

Then the final board is a Timeline PRX ASSY 70383.
More SRAMs and lattice chips, and a PLX PCI9060 bus controller.
So I suspect that many-pins backplane they use to connect all the boards may be a second PCI bus.

It's also got a Motorola DSP56002PV80, a 24-bit DSP.

The front-panel display is a Optrex DMC-2026I display. 20x20 characters, each character being 5x8 pixels. This variant has a backlight, and it's built on the standard Hitachi HD44780 chip.

The front panel is communicated with through this MMR FP/UIB Interface, Assy 70301.

It's just a bunch of caps and resistors?

and it's got three 32mb SDRAMs.
So 96mb in total. That's a bunch for a Pentium 1!

So it's got a separate power supply inside the case, plugged into a splitter on the power button line. (which, on an AT system, carries the full AC wall voltage)
It provides ±18v at half an amp.

Those power these two boards (with room for a third, missing on this model)
This one is the MMR Input Converter, ASSY 70395. 8-channels.

And an MMR Output Converter, ASSY 70372.

And the floppy drive is a TEAC FD-235HF, one of the most common models of 3.5" floppy disk drives.

The back panel has two PCBs.
The top one is a Parallel Remote board, ASSY 70374

It's got 4 of these UCN6821A 8-channel line drivers.

Then the bottom board is the MMR Rear Panel, ASSY 70389.
Left to right, we've got Transport, Editor, two Lynx ports, Timecode Out/In, MIDI thru/out/in, video out/in, and word clock out/in.

The power supply is a US Power SP2-4200F, a 200 watt AT supply.
But modified to have a different connector for the front power switch, so it can be branched off to the other power supply.

So the front panel. There's three PCBs.
The big one is the 8 TRK FP-70311, which the other two little ones connect to.

No chips on the other side. Just a bunch of buttons and LEDs. Interesting there's some spots for buttons that aren't present here.

Doesn't seem to be any smarts on the board. Another of those UCN 5821A 8-channel drivers, and 5 Maxim MAX7219CWG LED drivers

Other two boards:
first an MMR Headphone Monitor, Assy 70396

and the MMR Transport SW, ASSY 70392.
I think these are combination buttons/lights.

So yeah. That's the box! I'll plug in my archive box and try to dump the drive later.

I lit up some of the buttons using a bench power supply. Nice glow! I wonder if they're incandescent?

okay I dumped the hard drive

it's DOS 6.22

was not expecting that.

it also includes a shareware copy of PKZip 2.04g

come on TASCAM, pay for your shareware!