SBC6120 Front Panel

The FP6120 adds a traditional PDP-8/E style Programmer’s Console to any SBC6120 system. Twenty seven LEDS provide continuous display of the current memory address as well as memory or register contents, and a additional LED displays the running or halted state of the processor. Twelve data switches allow for direct entry of binary data and an additional eight switches provide program control functions including BOOT, ADDRESS LOAD, EXTENDED ADDRESS LOAD, CLEAR, CONTINUE, EXAMINE, DEPOSIT and HALT.

The FP6120 is designed as a peripheral device which plugs into the standard SBC6120 expansion bus, however because of its physical size the SBC6120 actually mounts directly to the back of the front panel. Additional space is available on the back of the FP6120 to mount another I/O board as well as either a CompactFlash memory card or a standard 2½” laptop hard disk drive. Finally, the FP6120 contains a switching power supply which can supply all necessary power for the SBC6120, one or two daughter boards, and the FP6120 itself from a single unregulated source of +9 to +12VDC.

The entire FP6120 and SBC6120 assembly, including a hard disk drive, is less than 2” thick and can be framed like a painting and hung on the wall. Just imagine it – a complete PDP-8/E clone, including disk drive, hanging on the wall above your desk!

The Faceplate

The front panel façade you see in these photos was custom manufactured for Spare Time Gizmos by the Ms Carita Corportation in Livermore California.  We owe a special thanks to Tom, Francine and the other people at MS Carita who helped make the faceplate a reality.  The colors came out great, the graphics artist in the print shop did an excellent job of cleaning up my text labels (which I could never get centered exactly right, the laser cut holes for the paddle switches are perfectly smooth and clean, and all the mounting holes line up just right with the PC board.

If you're interested in how they're made, it's a surprisingly complex process. The graphics are screen printed, with no less than five colors and five separate printing steps, onto a 15 mil (that's 0.015"!) polycarbonate film.   In a separate step a 3/16" thick piece of acrylic is laser cut to size and drilled for the mounting holes. The mounting hardware is then attached to the back of this panel and permanently glued into place.  In yet a third separate step, a sheet of adhesive film is cut to size and then stamped with a custom made die to cut out circular openings in the exact size and position of the LED windows. Now, those three separate pieces, the film with the graphics, the adhesive, and the 3/16" panel are all laminated together into a single piece and finally the entire thing is laser cut again for the switch openings.

One nice feature of this is that the faceplate is all one piece when you get it, so there's no complex assembly required on your part (like aligning and sandwiching a film between two sheets of plastic). Another nice feature is that the silkscreen is actually printed on the back side of the polycarbonate film, so that when it's assembled all the printing is protected by the 15 mil thick film. This means the graphics will never rub or wear off and they're even pretty hard to scratch (although I don't recommend you test this claim on your faceplate!).

Construction

The entire FP6120 is constructed on a single large (approximately 12.4 inches by 6.2 inches) double sided PC board.  The LEDs, switches and other electronic components mount on the front (component) side of the PC board, and the entire SBC6120 PC board mounts to the back side.

In the PDP-8/E, the front panel plugs into the computer, but in the SBC6120 the computer plugs into the front panel!

The large gray/black bar that you see across the front panel was also custom manufactured for Spare Time Gizmos by Philip Freidin of Fliptronics and is both an alignment fixture and a light well for the LEDs.  It keeps the LEDs, which have to be mounted approximately 9/16 of an inch above the PC board, straight and aligned with the holes in the front panel facade, and it keeps the light from one LED from leaking out of its neighbor's hole.

The row of white paddle switches and the rotary switch (less knob) are also clearly visible in this picture.  No, white switches are not the official PDP-8 colors, but they are the only color we had available to us (and we felt lucky to get them!).  The paddle switches used are approximately 0.500" wide, and this sets the scale for everything else.  The entire FP6120 is approximately 2/3rds of the size of an actual PDP-8/E front panel.

This picture shows the back (solder) side of the FP6120.  The SBC6120 is mounted in the middle, face down, and the IOB6120 (or any other daughter board) is mounted on the right, face up.  The space to the left of the SBC6120 contains mounting holes that can be used to attach a 2.5" laptop hard disk drive, or a CompactFlash adapter (in addition to the CF socket on the IOB6120).

Enclosure

Spare Time Gizmos does not currently supply any enclosure for the front panel, however because of the FP6120's construction in which everything mounts to the faceplate, including the front panel PC board, SBC6120 and any I/O boards, you can simply take the entire thing to any art supply store and have it framed, like a painting or photograph.  The frame depth will be approximately two inches, depending on the I/O daughter card installed.  This final picture shows Debee holding the completed SBC6120/FP6120 combination mounted in a stylish black anodized aluminum picture frame. 
 

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