A modern CAD replica of the LC-67183-1 relay board from the power supply of a Yamaha CR-2020 reciever.
This project faithfully recreates the original board based on a sample LC-67183-1 board from a 1976 North American market CR-2020. A complete BOM is provided, including modern part substitutions where original parts may not be available. The KiCAD project files are available for download from this repository (direct link).
The replica doesn't perfectly recreate original board - some liberties were taken to make the design more suitable for modern components, and to make some practical changes.
AK user Jayfree also designed a replacement for the relay board, his is a modernized two-layer design instead of a reproduction of the original design. Available here: https://www.audiokarma.org/forums/index.php?threads/cad-new-yamaha-cr-2020-capacitor-board.912553/page-7#post-14397551 (Photo)
Replica filter capacitor boards have been made as well:
- niclasf's board - to get one, contact niclasf on AK, or use his web store at https://www.facebook.com/foogadgets/
- jayfree's board - (Photo)
- There are some small differences between model years, but as far as I can tell, this board should work for any model year. Check your CR-2020's power supply carefully before trying to use this reproduction board.
- At least 2oz copper is required for the PCB.
- The board's silkscreen includes very small text which isn't always clearly readable. A PDF export of the silkscreen markings is included for reference.
- Read this thread first: https://www.audiokarma.org/forums/index.php?threads/cad-new-yamaha-cr-2020-capacitor-board.912553/
A collection of reference information useful for working on the CR-2020 is included in this repo. The collection contains:
- Recap BOMs for all CR-2020 PCBs
- Broken-out PCB diagrams with some corrections made for misprints and errors in the original diagrams
- Datasheets for many of the original transistors and diodes
- Service Manual and power supply service bulletins
- High resolution copies of the block diagram, schematic diagram, and wiring diagram
Most of this information can be found on the Internet already, but hopefully this collection will save time for those working on a CR-2020.
https://github.com/flakzilla/cr2020-relay-board/tree/main/CR-2020%20reference%20information
The author would like to thank AudioKarma users avionic, niclasf, and jayfree. Owe each of you a beer or 3. :)
Recommend JLCPCB: https://jlcpcb.com/.
Prepared gerber files for this board: Gerbers, v1.0
Board requires 1.6mm PCB thickness and 2oz copper weight. Thicker copper is mandatory due to high current passing through the relay.
BOM:
Carefully read and understand the notes in the BOM sheet, and check everything against your own CR-2020. Plan to recover and reuse the factory TO-92 transistors. Note that this BOM is not compatible with Jayfree's modernized relay board (see the Summary section above).
Reference materials:
- Board diagram from the service manual, typos and mistakes present in the original diagram have been fixed
- PDF of PCB markings since the silkscreen text on the board might be too small to read clearly
- Some examples of TO-220 heatsinks that can be used for TR712/715
This project is released under the terms of the Creative Commons Attribution + Noncommercial + ShareAlike (BY-NC-SA) license. https://creativecommons.org/licenses/by-nc-sa/2.0/
This project is distributed 'as-is' in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.