Junior interface
About the Junior interface PCB
Junior interface is an open source PCB design by laurent-fr, published on GitHub under the CC-BY-NC-4.0 license. It is a 2-layer board measuring 217.2 × 113 mm, with 116 components from 61 distinct parts.
Other key parts include the 6522, 2114, 2716, NE565 and LM311. By type, the board carries 37 resistors, 32 connectors, 22 capacitors, 17 ICs, 3 transformers and 3 diodes.
It belongs with the retro computing designs in this gallery.
From the project
A replica of the Junior Computer (a KIM-1 clone) published by Elektor in the 80's
This is a replica of the expansion board for the Junior Computer, published in Elektor magazine in 1981
This is a replica PCB I made with KiCAD.
The best source of information for this computer is Elektor Magazine from 80's , but you can find a lot on this website : http://retro.hansotten.nl/6502-sbc/elektuur-junior/
I made some changes from the original : The board can only use 2716 Eproms, no 1K ROM or 1K EPROM The PROM used for bus read/write signals is replaced by a GAL * The RCA connectors for the tape are replaced by smaller 3.5mm jacks, which allows a better placement of DB25…
Main components on the Junior interface
Junior interface bill of materials (BOM)
116 components, 61 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 6522 | DIL-40 | IC1 |
| 2 | 2114 | DIL-18 | IC2, IC3 |
| 2 | 2716 | DIL-24 | IC4, IC5 |
| 1 | NE565 | DIL-14 | IC6 |
| 2 | LM311 | DIL-8 | IC7, IC8 |
| 2 | 74LS241 | DIL-20 | IC9, IC10 |
| 2 | 74LS243 | DIL-14 | IC11, IC12 |
| 1 | 74LS27 | DIL-14 | IC13 |
| 1 | 74LS01 | DIL-14 | IC14 |
| 1 | 74LS30 | DIL-14 | IC15 |
| 1 | 74LS00 | DIL-14 | IC16 |
| 1 | GAL16V8 | DIL-20 | IC17 |
| 4 | CONN_01X03_SOCKET Conn_01x03_Socket | Support-Jack-3.5 | J1, J2, J3, J4 |
| 6 | — | CONN-1 | J5, J21, J22, J23, J27, J40 |
| 1 | C64AC | DIN-41612-AC | J6 |
| 1 | C64AB | DIN-41612-AB | J7 |
| 1 | +5V | CONN-1 | J8 |
| 1 | DB25_FEMALE DB25_Female | DB25-F-CI | J10 |
| 1 | CONN_01X20_MALE Conn_01x20_Male | Conn-20-L | J11 |
| 2 | CONN_01X03_MALE Conn_01x03_Male | CONN-3 | J12, J30 |
Show 41 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | +12V | CONN-1 | J13 |
| 1 | -5V | CONN-1 | J14 |
| 1 | -12V | CONN-1 | J15 |
| 1 | 0 | CONN-1 | J16 |
| 4 | — | PIN | J17, J18, J19, J20 |
| 1 | P | CONN-1 | J24 |
| 1 | Q | CONN-1 | J25 |
| 1 | D4 | CONN-1 | J26 |
| 1 | D5 | CONN-1 | J28 |
| 1 | CONN_01X06_MALE Conn_01x06_Male | CONN-6 | J29 |
| 1 | 5k | POT-MULTITOUR | P1 |
| 1 | 1k | POT | P2 |
| 2 | relay_reed | DIL-14 | Re1, Re2 |
| 1 | BC547 | TO-92 | T1 |
| 2 | BC516 | TO-92 | T2, T3 |
| 3 | 1N4148 | Diod-4 | D1, D2, D3 |
| 1 | 220N 220n | CAP-3 | C1 |
| 4 | 10uF 16V | CAP-POL-3 | C2, C11, C12, C13 |
| 1 | 22N 22n | CAP-3 | C3 |
| 1 | 1n | CAP-3 | C4 |
| 3 | 6N8 6n8 | CAP-3 | C5, C6, C7 |
| 1 | 100N 100n | CAP-3 | C8 |
| 1 | 47N 47n | CAP-3 | C9 |
| 7 | 1uF 16V | CAP-POL-3 | C10, C14, C16, C18, C19, C20, C22 |
| 2 | 1uF 16V | CAP-POL-2 | C15, C21 |
| 1 | 1uF 16V | CAP-POL-2.5 | C17 |
| 8 | 1K | Res-5 | R1, R2, R3, R4, R32, R33, R34, R35 |
| 1 | 22K 22k | Res-5 | R5 |
| 9 | 10K 10k | Res-5 | R6, R10, R11, R14, R15, R24, R26, R27 +1 |
| 3 | 8K2 8k2 | Res-5 | R7, R8, R36 |
| 4 | 4K7 4k7 | Res-5 | R9, R18, R22, R23 |
| 1 | 6K8 6k8 | Res-5 | R12 |
| 3 | 2K2 2k2 | Res-5 | R13, R25, R31 |
| 1 | 100 | Res-5 | R16 |
| 1 | 330 | Res-5 | R17 |
| 1 | 470 | Res-5 | R19 |
| 1 | 1K2 1k2 | Res-5 | R20 |
| 1 | 15K 15k | Res-5 | R21 |
| 1 | 33K 33k | Res-5 | R29 |
| 1 | 4M7 | Res-5 | R30 |
| 1 | 33 | Res-5 | R37 |
Junior interface design files
The KiCad project lives in the laurent-fr/junior_computer_replica repository on GitHub; these links point at the commit this page was built from.
Junior interface: common questions
How big is the Junior interface PCB?
The Junior interface measures 217.2 × 113 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Junior interface?
116 components, from 61 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Junior interface design files?
From the laurent-fr/junior_computer_replica repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Junior interface design in my own project?
It is published under CC-BY-NC-4.0, which limits how it may be reused; read the license before building on it.
More boards in junior_computer_replica
Junior computer
217.2 × 113 mm80 parts2LCC-BY-NC-4.013
Junior computer - Copie
204.5 × 104.1 mm77 parts2LCC-BY-NC-4.013
Junior universal memory
160 × 100 mm38 parts2LCC-BY-NC-4.013
Junior bus
116.8 × 100 mm13 parts2LCC-BY-NC-4.013
Junior interface conn
91.4 × 19.7 mm9 parts2LCC-BY-NC-4.013
Junior computer display
77.5 × 31.8 mm7 parts2LCC-BY-NC-4.013
Ram adapter
34.3 × 33 mm5 parts2LCC-BY-NC-4.013
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