Top from left to right:
| 6HP Panel | with power switch |
| Vero Bivolt PK60 PSU module (8HP) | providing 5V@6A and +12V@2A |
| LCD Monitor Module | my design |
| Dual 5.25" Floppy Disk Module (Horizontal) (42HP) | my design with a GOTEK in a 3.5" bay adapter (0/2) and a 5.25" 40T DS TEAC FD-55BR drive (1/3) |
Bottom from left to right:
| 14HP Panel | with reset switch |
| 6502 CPU Cassette Board | System 1 Trainer in Rack Mount Configuration |
| 40x25 VDU (Teletext) Interface Board | my replica |
| Versatile Interface Board | my replica |
| CUMEM | my replica with 8K RAM, DOS40B, NFS, BASIC and FP in 2532 EPROMs |
| 32K Dynamic RAM Board | original Acorn Board with 32K DRAM |
| Floppy Disk Controller Board | my replica |
| Econet Node Board | my replica (ID14) |
| PROM Programmer Board | my replica |
| Tesla PROM Programmer Board | my design |
| 4 spare slots |
The CUMEM Board is fitted with DOS40B in a 2532 EPROM, the memory board is fitted with BASIC and FP Extension in 2532 EPROMs. The two memory boards provide 40k of continuous memory from 2000 to BFFF.
Rather than use a pair of 3U Card Frames attached one above the other, as I think the original Acorn System 4 was built, I have built a 6U high Card Frame. This is fitted with an original Acorn 14-slot Backplane, this has had the Side-B connections made as well using a a length of Veroboard.
Acorn must have had a bespoke PSU module that plugged into the 32-way sockets on the left of the backplane. I have used a Vero Bivolt PSU which plugs into an H15 type socket, this is attached directly to the card frame and the power supply wired to the backplane. The 14HP panel conceals the two 32-way sockets and provides a mounting for a reset switch, the mains on/off switch is attached to the upper 6HP panel.
Card Frame Details
The Card Frame is 6U high, 84HP wide and 240mm deep (1U = 1¾" or 44.45mm, 1HP = 5.08mm).
|
Part |
Dimensions |
Quantity |
Original Vero KM6 Part No. |
VeroTec KM6-II Equivalent Part No. |
|
End Plate |
6U x 240mm |
2 |
173-12535J |
|
|
End Plate Front Angle |
6U |
2 |
173-12540J |
|
|
Upper Front Tie Bar |
84HP |
1 |
173-12552K |
|
|
Lower Front Tie Bar |
84HP |
1 |
173-12551B |
|
|
Upper Rear Connector Mounting Rail |
84HP |
1 |
173-13018E |
|
|
Lower Rear Connector Mounting Rail |
84HP |
1 |
173-12701A |
|
|
Front Location Moulding |
|
2 |
173-12557F |
not required |
|
Rear Location Moulding |
|
2 |
173-12558C |
|
|
Tapped Strip |
84HP |
|
173-12704C |
|
|
|
160mm |
44 |
173-12553G |
|
|
Module Guide |
160mm |
4 |
173-12554D |
|
|
Front Panel |
|
|
|
|
|
Front Panel |
3U x 6HP |
1 |
174-12904G |
957-235351K |
|
Front Panel |
3U x 14HP |
1 |
174-12910D |
957-235357J |
|
Module |
3U x 42HP x 160mm |
1 |
174-12929F |
957-235950K |
|
Screws |
M4 x 12mm |
10 |
173-12529A |