Mainboard
About the Mainboard PCB
Mainboard is an open source PCB design by btb, published on GitHub. It is a 2-layer board measuring 414.3 × 266.7 mm, with 155 components from 58 distinct parts.
Other key parts include the 6116, 2716, MC6800, 74LS241 and 7408. By type, the board carries 73 ICs, 43 capacitors, 24 resistors, 3 transistors, 3 diodes and 1 module.
From the project
The Telcon Ambassador was a series of portable terminals by Telcon Industries (who later created the Zorba portable computer).
The Telcon Ambassador was a series of portable terminals by Telcon Industries (who later created the Zorba portable computer).
The info here is primarily derived from my reverse-engineering of a Telcon Ambassador IV which I acquired in very rough shape.
Main components on the Mainboard
Mainboard bill of materials (BOM)
155 components, 58 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | 6116 | DIP-24_W15.24mm | U3, U4 |
| 2 | 2716 | DIP-24_W15.24mm | U5, U6 |
| 1 | MC6800 | DIP-40_W15.24mm | U7 |
| 3 | 74LS241 | DIP-20_W7.62mm | U8, U9, U56 |
| 3 | 7408 | DIP-14_W7.62mm | U10, U39, U53 |
| 4 | 7400 | DIP-14_W7.62mm | U11, U33, U50, U67 |
| 5 | 7404 | DIP-14_W7.62mm | U12, U43, U51, U75, U76 |
| 3 | 74S139 | DIP-16_W7.62mm | U13, U14, U21 |
| 12 | 74163 | DIP-16_W7.62mm | U15, U16, U17, U30, U31, U32, U35, U36 +4 |
| 3 | 74157 | DIP-16_W7.62mm | U18, U19, U20 |
| 6 | MM2114 | DIP-18_W7.62mm | U22, U23, U24, U26, U27, U28 |
| 7 | 7474 | DIP-14_W7.62mm | U34, U41, U63, U64, U65, U66, U72 |
| 2 | 7420 | DIP-14_W7.62mm | U38, U54 |
| 2 | 74S138 | DIP-16_W7.62mm | U40, U52 |
| 1 | 12.5MHZ | Oscillator_DIP-14 | U44 |
| 1 | 74LS163 | DIP-16_W7.62mm | U45 |
| 1 | 6810 | DIP-24_W15.24mm | U47 |
| 3 | 74175 | DIP-16_W7.62mm | U58, U59, U68 |
| 1 | 2758 | DIP-24_W15.24mm | U60 |
| 1 | 74166 | DIP-16_W7.62mm | U61 |
Show 38 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 7486 | DIP-14_W7.62mm | U62 |
| 1 | 5307 | DIP-14_W7.62mm | U69 |
| 2 | 6821 | DIP-40_W15.24mm | U70, U71 |
| 2 | 75150_2 | DIP-8_W7.62mm | U73, U79 |
| 1 | 8251 | DIP-28_W15.24mm | U74 |
| 2 | 75154 | DIP-16_W7.62mm | U77, U78 |
| 1 | 7414 | DIP-14_W7.62mm | U80 |
| 1 | Conn_01x05 | SolderWire-0.75sqmm_1x05_P6.35mm_D1.25mm_OD2.3mm | A1 |
| 3 | 2N3904 | TO-92_Inline | Q1, Q2, Q3 |
| 1 | 921.6KHZ | Crystal_HC33-U_Horizontal_1EP_style2 | Y1 |
| 1 | Presets | DIP-16_W7.62mm | P1 |
| 1 | Conn_01x04 | SolderWire-2sqmm_1x04_P7.8mm_D2mm_OD3.9mm | B1 |
| 1 | Conn_01x20 | SolderWire-0.75sqmm_1x020_P3.96mm_D1.25mm_OD2.3mm | JC1 |
| 1 | Jumper_2_Bridged | SolderWire-0.5sqmm_1x02_P10.16mm_D0.9mm_OD2.1mm | JW1 |
| 1 | Jumper_2_Bridged | SolderWire-0.5sqmm_1x02_P12.7mm_D0.9mm_OD2.1mm | JW2 |
| 1 | Speaker | Buzzer_15x7.5RM7.6 | LS1 |
| 1 | TestPoint | TestPoint_THTPad_1.0x1.0mm_Drill0.5mm | TP1 |
| 1 | Conn_01x21 | SolderWire-0.75sqmm_1x021_P3.96mm_D1.25mm_OD2.3mm | D1 |
| 2 | 1N4148 | D_DO-35_SOD27_P7.62mm_Horizontal | D2, D17 |
| 39 | 220nF | C_Disc_D4.3mm_W1.9mm_P6.35mm | C1, C2, C3, C4, C5, C6, C7, C8 +31 |
| 1 | 10 | CP_Radial_Tantal_D4.5mm_P5.00mm | C23 |
| 1 | 22 | C_Disc_D11.0mm_W5.0mm_P7.50mm | C24 |
| 1 | 130PF | C_Disc_D11.0mm_W5.0mm_P7.50mm | C25 |
| 1 | C_Polarized_US | CP_Axial_L18.0mm_D10.0mm_P25.00mm_Horizontal | C26 |
| 1 | 3.9K | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R1 |
| 1 | 10 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R2 |
| 6 | 220 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R3, R4, R5, R6, R7, R8 |
| 1 | heatshrink bodge | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R9 |
| 2 | 3.3K | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R10, R11 |
| 2 | 680 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R12, R14 |
| 2 | 150 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R13, R15 |
| 2 | 4K7 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R16, R18 |
| 1 | 6M2 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R17 |
| 1 | 100 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R171 |
| 1 | 47K | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R172 |
| 1 | R_Network09_US | R_Array_SIP10 | RN1 |
| 2 | 3.3K | R_Array_SIP10 | RN2, RN3 |
| 1 | R_Network09_Split | R_Array_SIP10 | RN4 |
Mainboard design files
The KiCad project lives in the btb/Telcon-Ambassador repository on GitHub; these links point at the commit this page was built from.
Mainboard: common questions
How big is the Mainboard PCB?
The Mainboard measures 414.3 × 266.7 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Mainboard?
155 components, from 58 distinct parts. The full bill of materials is listed on this page.
Where can I download the Mainboard design files?
From the btb/Telcon-Ambassador repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Mainboard design in my own project?
The repository has no license, so all rights stay with btb. Use it as a reference, and ask the author before reusing the design.
