Recovering old PCB data: from films and dead CAD formats to current files
Sometimes the data still exists – but nobody can open it. A Protel project from the 1990s, Gerber files without aperture lists or a box of photo films. In most cases this can be converted into data today's fabricators accept.
Updated:
Formats we regularly see
| Format | Problem | What we do |
|---|---|---|
| Gerber RS-274D | Old standard without embedded apertures; needs a separate aperture list | Reconstruct apertures, convert to RS-274X / Gerber X2 |
| Gerber RS-274X | Readable, but often no netlist, outline or stack-up | Check against the board, add missing layers and drawings |
| Excellon / drill files | Missing tool table or units unclear | Reconstruct from the board and the Gerber data |
| Protel, old Altium, OrCAD, PADS, Eagle | Software or licence no longer available | Import and convert to KiCad, or recapture |
| Photo films and paper plots | Only analogue copies exist | High-resolution scan, scale calibration, vectorisation |
| HPGL or DXF from old drawings | Geometry without electrical meaning | Use for the outline and mechanical data |
Why converted data must be checked
Old files are often not the last revision. Boards were modified on the production line, wire bridges were added, components changed. A conversion without comparing it to a real board can reproduce an outdated version. We therefore always compare the converted data with a physical sample or with photos of it.
Which formats you receive
- Gerber X2 or RS-274X and Excellon – accepted by practically every fabricator worldwide
- ODB++ or IPC-2581 on request, for fabricators that prefer an intelligent format
- An editable KiCad project – open source, free and readable in ten years
- PDF drawings for fabrication and assembly
Keeping data usable for the future
Store each board revision as a complete, self-contained package: manufacturing files, BOM, drawings and a short readme with revision, date and changes. Keep at least one open format. That turns the next obsolescence case from a rescue project into a routine order.
Questions
Can you convert Gerber files back into a schematic?
Gerber files contain only geometry, not the circuit. We can rebuild the netlist from the copper and draw a schematic from it; the component values come from the BOM or the board.
What if I only have a paper plot?
If the scale is known or a dimension is printed on it, a high-resolution scan can be vectorised. The result is then checked against a board.