DIP switches:

reset circuit:

clock source:

address decoding:

DE-9F connections, for main RS-232:

ACIA1 crystal circuit:

ACIA2 circuit (primarily for MIDI and Lynx wireless connections)

MIDI cable to musical keyboard:

ACIA3 circuit (which was intended for tape modem, which is now obsolete):

A/D converter circuit:

There's another page farther down showing how this is connected to the outside world.

DIP header for A/D's op amp parts:

D/A converter circuit:

There's another page farther down showing how this is connected to the outside world.

SS22 interface:

parallel printer connector pinout:

the mass of stuff interfaced via VIA1
From top to bottom: NMI is used with T1 for realtime clock & calendar plus Abort key circuit (shown at the bottom); then there's a synchronous-serial port, beeper, I²C, printer, LCD, keypad, and Abort circuit:

front panel layout:

The round A/D and D/A connectors are 3.5mm 3-conductor jacks.

The four larger annunciator LEDs here are turned on and off by software, so you can use them to monitor where you are in a program.  In Forth, you can use lines like

   TURN ON #2 LED

   TURN OFF #4 LED

remote LCD and keypad header:

remote keypad diagram:

front-panel Abort key circuit:

front-panel I²C port (compatible with I2C-6, but this was before we added I2C-6's interrupt pin and keyway):

front-panel frequency/event counter & control header:

D/A anti-alias filter socket, and front-panel D/A connections:

(This is the page shown in the picture at the end of the main web page about workbench computers.)

A/D anti-alias filter socket, and front-panel A/D connections:

data converter socket locations:

mezzanine connections:

maximum mezzanine dimensions:

mezzanine parts locations:

mezzanine circuit for 65SIB, also PC keyboard and Dallas Semiconductor's (Dallas in now part of Maxim) 1-Wire interface:
I should have put a DIP switch on one of the 138's E inputs so an uninitialized VIA3PB doesn't enable anything, and S7 (switch 7) should optionally disable IRQs by shorting D4-A to ground.

65SIB header pinout on mezzanine:

mezzanine header for raster graphics on an analog oscilloscope and for large memory on a serial interface:

raster graphics on an analog oscilloscope, circuit built up on a separate board, not on Bench-1:

LCD characters.  This page is cut out from a data sheet, and needed to be folded to fit in the tiny ring binder.

other side of the LCD character page, showing instructions:

LCD instructions, put another way:

and other side:

board-edge connector pinout:

regulator circuit:

The .25" 3-conductor phone jack for power was not a very good choice.  I'm not sure what the best would be; but there are a lot of things that need a higher plus and minus voltage (rather than just +5V or +3.3V), so unless you convert the voltage on the board itself with switching regulators, I still suggest using a plus and minus input, like ±10V.  The exact voltage is not critical at all for most things.  I use it to power:

• the LT1124 op amps for the A/D and D/A converter input and output circuits,
• the sockets for the anti-alias filters (which have op amps on them too),
• the MC145406 (same thing as the SN75C1406) 16-pin triple line drivers and receivers (which have more channels and take less board space than the popular MAX232),
• my home-made PIC microcontroller programmer which needs a +13V Vpp for most PICs,
• and some supertwist LCDs need a negative backplane voltage.
• The 65SIB port delivers the ± voltage for 65SIB devices as well, partly so devices won't need their own power supply and they can have local 78L05 or similar regulators so power-supply I²R losses on the ribbon cable don't cause problems, and so they can also use parts that require the higher voltages if needed.