Related to Obsolete Electronics Replacement & Redesign
Functional redesign of legacy electronics: keep the functions, modernise the design
Functional redesign is the route for legacy electronics when exact physical compatibility is not required: the functions the equipment depends on are preserved, while the architecture, components, construction and, where agreed, interfaces are modernised. Micro Digital Engineering defines what must be preserved and what may change, develops the new design and verifies by test that the required functions are kept.
Confidential task? We sign an NDA before you share technical files.
When is functional redesign better than repeating the old board?
When repeating the old board would also repeat its limitations: parts that are hard to source, several boards that could be one, known weaknesses of the original design, or missing functions such as monitoring and communication. If the equipment can accept a different board, connector or mounting, a redesign usually gives a more maintainable result than an exact copy.
When functional redesign is the right route
- Several old boards can be combined into one current design.
- The equipment’s functions must stay, but its electronics can change form.
- New functions, such as monitoring or communication, have to be added at the same time.
- An exact replacement would preserve problems of the original design.
- The original concept depends on components or technology that no longer exist.
What may change and what must be preserved
What may change, when agreed
The number of boards and the architecture, the components and their technology, the dimensions, mounting and connectors, the firmware and its microcontroller, and interfaces whose connected equipment is adapted at the same time.
What must be preserved
The functions the equipment depends on, the behaviour at every interface that stays unchanged, protection and safety functions, the agreed performance limits such as accuracy, timing and power, and the behaviour visible to operators, such as indications and settings.
Both lists are agreed in writing before design starts and become the acceptance requirements of the project.
How the preservation of functions is verified
- Function list. The functions of the original are established from the existing design, documentation and measurements, if needed with reverse engineering, and turned into requirements.
- Bench tests. The new design is tested against each requirement, and against the original unit where one is available, with measurements made with calibrated equipment.
- Changed interfaces. Where an interface changes, it is tested together with the adapted connected equipment.
- Tests in the equipment. The redesigned electronics is tested in the equipment under acceptance criteria agreed with you.
How the routes differ
| Route | What you receive |
|---|---|
| Obsolete electronics replacement | The choice of replacement route for an obsolete unit, and its implementation |
| Compatible replacement board | A board with agreed form, fit and function compatibility with the original |
| Functional redesign (this page) | A new electronic architecture that keeps the required functions, while construction, components and interfaces may change |
What’s included
Analysis of the existing electronics and its role in the equipment, the agreed lists of preserved and changeable features, architecture of the new design, schematics and PCB, firmware when needed, PCB fabrication through a manufacturing partner, in-house prototype assembly and bring-up, bench tests, tests in the equipment and documentation for repeat manufacturing.
PCB fabrication is performed by specialised manufacturing partners. Prototype component assembly, bring-up, debugging and verification are carried out in-house by our engineering team.
What you receive
| Deliverable | Format | How it is checked |
|---|---|---|
| Functional requirements | Document: preserved functions, permitted changes, acceptance criteria | Review and written approval |
| New architecture | Document: boards, interfaces, firmware platform | Design review |
| Schematics, PCB and BOM | Design files in the agreed format | Design review, availability check |
| Firmware, when needed | Source code with build instructions | Tests on the prototype |
| Prototypes, assembled in-house | The agreed number of units | Bench tests, then tests in the equipment |
| Verification report | Document | Results against each preserved function |
| Manufacturing package | Gerber or ODB++, assembly drawings, BOM | Review against the manufacturer’s requirements |
How the project runs
- You confirm that you own the equipment or are authorised to maintain it.
- The existing electronics and its functions in the equipment are analysed.
- The preserved functions, the permitted changes and the acceptance criteria are agreed in writing.
- The new architecture is defined and reviewed with you.
- Schematics, PCB and firmware are developed.
- The bare PCBs are fabricated by a manufacturing partner; the prototypes are assembled and brought up in-house.
- The prototypes are verified on the bench and in the equipment.
- Design files, verification report and manufacturing package are handed over.
See how we work.
What to send us
- A description of the equipment and the electronics to be redesigned.
- What must be preserved, and what you would like to change or add.
- Existing documentation, samples and a working unit if available.
- Constraints on the equipment side: space, connectors, cabling, standards.
Common questions
Can new functions be added during the redesign?
Yes. Monitoring, communication or diagnostics can be added as part of the new architecture, see also industrial equipment telemetry.
Will the equipment itself have to change?
Only as far as agreed. If mounting, connectors or cabling change, the required changes on the equipment side are listed in the requirements before design starts.
Can several old boards be replaced by one?
Yes, when their functions and interfaces allow it. Combining boards is one of the typical reasons for a functional redesign.
Does a redesign affect conformity of the equipment?
It can. Where the changes may affect conformity with the standards that apply to the equipment, this is identified at the start, and any repeat assessment is planned with you.
Related services
- Obsolete electronics replacement and redesign — choosing the route.
- Compatible replacement boards — when form, fit and function must stay the same.
- PCB reverse engineering — analysis of the original electronics.
- Firmware recovery and migration — when functions are implemented in firmware.
Discuss a redesign
Describe the equipment, the electronics to be replaced and what has to be preserved.
Confidential task? We sign an NDA before you share technical files.