Reconstructing schematic from two layer PCB - Page 1
Forum section: electronics / projects

author: bigmac
author_rank: Newbie
timestamp: January 03, 2020, 10:36:35 am
content: So... i've got myself into a bit of a project.Quick story.I bought an electric car, a Kewet El-Jet 4 from 1995. Not working. Turned out it had the wrong type of computer installed.So.. I sourced another El-Jet 4 in order to get the computer.My plan is to copy the computer.so i ripped the computer out, photographed it, documented all of the parts, desoldered, scanned, retraced in sprint layout....but now i'm kinda stuck. I can export gerbers from Sprint layout, but to where? What would be the best route here? (pun intended) thank you

author: mc172
author_rank: Frequent Contributor
timestamp: January 03, 2020, 10:57:18 am
content: Why do you need the schematic in order to make a copy? If you've copied the layout and know all of the component values, that's all you need.

author: Rerouter
author_rank: Super Contributor
timestamp: January 03, 2020, 11:02:21 am
content: kicad can import the gerbers and allow you to edit them, and I suspect rebuild into a schematic + project, I just have not used it in this manner before,

author: digsys
author_rank: Unknown
timestamp: January 03, 2020, 11:54:58 am
content: If you have all the board details, why not source a spare board or two off ebay / alibaba / aliexpress etc etcI've found heaps of rare boards for various project I do, rarely failed to find one. Or do you intend to mass produce them?

author: mikerj
author_rank: Super Contributor
timestamp: January 03, 2020, 12:43:21 pm
content: Easy-PCcan apparently do this, though it's a pretty expensive licence for a hobbyist.Quote from: mc172 on January 03, 2020, 10:57:18 amIf he's also reverse engineering the firmware then a schematic is going to be pretty essential to understand the operation of the board and debug it.

author: Yansi
author_rank: Super Contributor
timestamp: January 03, 2020, 12:51:18 pm
content: Problem is, it is not a two layer, but a four layer PCB, or you have a lot of traces missing.Dead giveaway is the JP7 at the bottom, which is a RS232 connector, missing a GND connection from pin 5, that likely is going to an internal GND layer.

author: mikerj
author_rank: Super Contributor
timestamp: January 03, 2020, 01:07:19 pm
content: Quote from: Yansi on January 03, 2020, 12:51:18 pmAgreed, most of the bypass caps show only one pin connected, and C16 has no pins connected. A large number of unconnected IC pins as well.

author: tooki
author_rank: Super Contributor
timestamp: January 03, 2020, 01:13:47 pm
content: Besides, are the ROMs even copyable? If it uses a CPU or MPU with mask ROM or read-only EPROM, then even if you copy the board, it’d be useless.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: January 03, 2020, 02:43:04 pm
content: Quote from: tooki on January 03, 2020, 01:13:47 pmThe current project I'm working on is exactly doing that. In fact, it's of similar vintage so maybe it's the same CPU?"Is it possible to learn thispowerROM?""Not from aJedimask"

author: bigmac
author_rank: Newbie
timestamp: January 03, 2020, 03:39:46 pm
content: Quote from: mikerj on January 03, 2020, 01:07:19 pmGround planes on both sides. Removed for clarity. Good spotting though!

author: bigmac
author_rank: Newbie
timestamp: January 03, 2020, 03:46:11 pm
content: Latest gerbers uploaded. If anyone could give me a hint on how to proceed id be very thankful thanks

author: ebclr
author_rank: Super Contributor
timestamp: January 03, 2020, 10:03:05 pm
content: If you are looking for a paid service those guys may help youhttps://www.pcbic-reverse.com