ECB 12-Slot Backplane for Siemens 505-6508


This is a 12-slot ECB backplane specifically designed to replace the backplane in the Siemens 505-6508 chassis unit, which can be readily obtained as a surplus item. This give the builder the opportunity to place their ECB system inside a nice case. Pictures on this page show version 1 whcih features different component placement and an on board regulator.

Hardware Documentation

Build Information

Parts List

Wiring Instructions

22 yellow jumpers: install to complete the Interrupt and DMA priority chains. I omit them, since only Zilog Peripherals board uses them; no other N8VEM board does.

2 blue (*) asterisks: Install only if you will be using Kontron-compatible RESET. All of your boards must be jumpered for Kontron compatibility to use these inputs. This admonition applies to SW2 and P81. All N8VEM legacy boards drive connector pin C31 from the CPU board, and a short to ground could blow the driver chip. If in doubt, do not stuff either component.

LED colors – recommended color code: +12v (yellow), +5v (red), Vcc ON (green).

3 green circles: Power connection. If using the Siemens 505-6508 chassis, it is suggested that SW1 and power connector P2 not be stuffed. Instead, solder connections to +12v(optional), GND, and +5v at the points indicated. Short SW1 to take advantage of C26 and C23, below.

Note that the +12v connection goes only the the LED monitor. It connects nowhere on the backplane. +12v is used by disk drives which may accompany the backplane and N8VEM circuit boards. N8VEM boards connect only to Vcc(5v) at A1,B1,C1, and to GND at A32,B32,C32.

White rectangle: For all power connections, stuff these two components, C26 and C23.

Construction Notes/Suggestions

Extended Backplane 12-slot rev. 1.0-002 23-Sep-2015 John Coffman

  1. The 12-slot backplane may be used stand-alone or with the Siemens 505-6508 chassis. If used stand-alone, say, mounted to a plywood backing, support should be provided at both ends of each of the DIN 41612 connectors.
  2. The RESET switch and 2-pin connector should not be used with older N8VEM boards which do not support the Kontron-compatible RESET operation. If the RESET switch or connector is used, then all boards should be set for “Kontron-compatible” RESET function.
  3. Suggested LED colors are : RED for +5v on power input; GREEN for +5v power switch ON; YELLOW for +12v on power input. The +12v is not connected to any pin on any of the 96-pin DIN 41612 sockets. The 1K current limiting resistor on the Yellow LED may be increased to as much as 4.7K to restrict the brightness of the Yellow LED. I suggest you try a couple resistor values to achieve brightness comparable to the Red and Green LED's.
  4. Additional decoupling is strongly recommended. Electrolytic caps chosen for their small size, in the range 100-470uF should be substituted for about 6-8 of the 0.1uF caps, both above and below the line of DIN connectors. The board is not marked for polarity, so be very careful to orient them correctly. Suggest use 6-8 x 220uF.
  5. Female 96-pin DIN 41612 connectors to use: (“x” denotes pin finish, gold or nickel) AMP 535090-x 0.130” short pins – best for this 12-slot (1/16” board thickness) AMP 535043-x 0.180” long pins (suit 8-slot backplane 1/8” board thickness) Either connector may be used with either backplane, but the long pins are unnecessary on the 12-slot backplane.
  6. Not all connector positions need be filled. Boards in the process of debugging will likely be inserted spaced farther apart.
  7. The 8-slot backplane uses 3/8” 4-40 pan-head screws & nuts (optional). The 12-slot backplane is 1/16” thinner, so a shorter screw may be used. The 96 solder positions make the use of nuts & bolts optional. (Metric size M2.5, of similar length.)
  • RetroBrew boards that plug into the Backplanes may use the following connector, or others: AMP 650913-x right angle, male connector.
  • I recommend this connector because it has tabs that may be soldered to the board mounting holes for physical stability. It does not need M3 or 4-40 hardware to solidly anchor it to the board.

File List

FilenameFilesizeLast modified
545-8101-2.pdf695.4 KiB2019/01/09 08:49
archive_-_version_001.zip1.2 MiB2015/10/31 00:34
bkpl12-6508-002-gerber.zip207.0 KiB2019/01/09 07:49
bkpl12-6508-002-kicad.zip2.4 MiB2019/01/09 07:56
extbackplane6508-brd-002.pdf768.1 KiB2015/10/31 00:34
extbackplane6508-sch-002.pdf712.0 KiB2015/10/31 00:34
extbkpln-6508-wiring-instructions.txt1.6 KiB2015/11/01 23:24
extbkpln6508-parts-002.txt1.8 KiB2015/11/01 23:24
boards/ecb/backplane-505-6508/start.txt · Last modified: 2019/02/08 19:46 by b1ackmai1er
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