Replica of a 286 Mainboard
- V0.1 Initial revision 2022 made with Sprint-Layout
- V0.2 Silkscreen updated, component positions and mounting holes modified
- V0.3 First working revision
- V0.4 Switch to KiCAD, still some RAM errors
- V0.5 Stabel System at 20Mhz with no RAM errors :-)
This replica of a 286 motherboard is based on the Headland HT12P-16/A chipset. It supports 286 CPUs.
Top view
| Quantity | Description | PCB/Schematic's Reference |
|---|---|---|
| 17 | CAP ELKO 10 uF 25 V | C1, C6, C9, C11, C15, C17, C22, C24, C27, C30, C34, C36, C49, C66, C67, C68, C69 |
| 39 | CAP CER 100 nF RM 5,0 | C2, C3, C4, C7, C8, C13, C14, C18, C20, C21, C25, C28, C29, C31, C35, C39, C40, C41, C42, C43, C44, C45, C46, C50, C51, C52, C53, C55, C56, C57, C58, C59, C60, C61, C62, C64, C65, C70, CXX |
| 2 | CAP CER 15 pF RM 5,0 | C32, C33 |
| 1 | CAP CER 27 pF RM 5,0 | C12 |
| 3 | CAP CER 47 pF RM 5,0 | C38, C47, C48 |
| 1 | CAP CER 4.7 nF RM 5 | C19 |
| n.c. | C5, C10, C16, C23, C26 | |
| 4 | DIODE 1N4148 | D1, D2, D3, D4 |
| 1 | CON 5 PIN | J1 Keylock & Power LED |
| 2 | CON 4 PIN | J2 Speaker, J6 Battery |
| 3 | CON 2 PIN | J3 Turbo LED, J4 Turbo switch, J5 Reset switch, JP1 Monochrome/Color |
| 1 | CON AT Power connector | CN1 Power |
| 1 | CON DIN 5 | CN2 Keyboard |
| 2 | Ferrite | L1, L2 |
| 1 | Quarz 32 MHz | OSC1 |
| 1 | Quarz 14.31818 MHz | OSC2 |
| 2 | 3904 | Q1, Q3 |
| 1 | 3906 | Q2 |
| n.c. | R15, R29, R37, R38, RP1, RP3 | |
| 1 | RES 22 Ohm 5% 1/4W | R27 |
| 8 | RES 33 Ohm 5% 1/4W | R1, R2, R21, R22, R23, R24, R26, R31 |
| 1 | RES 47 Ohm 5% 1/4W | R34 |
| 2 | RES 150 Ohm 5% 1/4W | R3, R4 |
| 4 | RES 330 Ohm 5% 1/4W | R10, R11, R16, R20 |
| 4 | RES 470 Ohm 5% 1/4W | R5, R12, R14, R25 |
| 6 | RES 1 k Ohm 5% 1/4W | R6, R13, R17, R30, R39, R40 |
| 6 | RES 10 k Ohm 5% 1/4W | R8, R9, R18, R33, R35, R36 ?? |
| 1 | RES 51 k Ohm 5% 1/4W | R7 |
| 1 | RES 100 k Ohm 5% 1/4W | R28 |
| 2 | RES 2 M Ohm 5% 1/4W | R19, R32 |
| 1 | RES Network 22 Ohm 4x parallel | SIP1 |
| 4 | RES Network 47 Ohm 4x parallel | SIP2, SIP3, SIP4, SIP5 |
| 2 | RES Network 1 kOhm 9+1 Stern | RP2, RP7 |
| 7 | RES Network 10 kOhm 9+1 Stern | RP4, RP5, RP6, RP8, RP9, RP10, RP11 |
| 4 | CON 30 POL SIM | SIM1, SIM2, SIM3, SIM4 |
| 1 | CON 8 Bit ISA Socket | SL1 |
| 5 | CON 16 Bit ISA Socket | SL2, SL3, SL4, SL5, SL6 |
| 1 | 74LS244 | U1 |
| 3 | 74HCT373 | U2, U3, U10 |
| 1 | 74LS245 | U4 |
| 1 | 74HCT14 | U5 |
| 1 | HD146818P | U6 |
| 1 | 74LS245 | U7 |
| 1 | HT12P-16/A | U8 |
| 1 | 80C286 | U9 |
| 1 | P8042AH | U11 |
| 1 | 74F245 | U12 |
| 1 | BIOS HI | U13 |
| 1 | 80287 | U14 |
| 1 | BIOS LO | U15 |
| 2 | 41256 | U18, U19 |
| 8 | 44256 | U20, U21, U22, U23, U26, U27, U28, U29 |
| 0 | ??? | U24, U25 |
| 1 | 7406 | U30 |
| 1 | 74F125 | UX1 |
| 1 | 74LS86 | UX2 |
| 1 | Y1 | |
| 1 | 8 MHz | Y2 |
The project is free for non-commercial reproduktion. Do not sell it on ebay or other platforms for profit. Do not make a closed source. Share your experiences and ideas with the community.