When is a PCB Design required to be Redone or Spun Again?

A spin design is one version of a PCB layout that is created with a purpose of changing or modifying the previous version. A spin is usually done after testing a prototype, determining compliance, checking for any faults in operation in the field or changing suppliers.

Some typical reasons for making a spin are:

  • The lack of stability while starting working of the CPU
  • Faults at programming/debugging points
  • Unstable operation of USB, Ethernet, memory or wireless interfaces
  • Inefficient operation of power supply
  • Noise picked by sensors caused by clocks, LEDs, motors
  • Heating of the board inside the casing
  • EMI/EMC testing shows high level of radiation
  • Having problems with connectors, holes, and components dimensions according to casing design
  • Making certain points hard to access during manufacturing
  • A component being old or unavailable
  • Reduced level of yield of the manufacturing process
  • Reduction of price of manufacturing

A spin is done hurriedly without identifying the root cause of the problem.

How We Rescue an Existing PCB

Establish a Reliable Design Baseline

We begin by collecting the available schematic, PCB source, Gerber files, BOM, firmware, enclosure model, test records and known failure reports.

Not every inherited project has complete source files. When editable data is missing, we determine what can be recovered from fabrication outputs, assembled boards, photographs and measurements. Assumptions are recorded instead of silently being treated as facts.

We also identify the hardware revision used in each test. This prevents conclusions from one revision being applied incorrectly to another.

Reproduce the Failure

A problem that cannot be reproduced is difficult to fix confidently. We define the conditions under which the failure occurs: input voltage, temperature, load, cable, radio activity, firmware version and enclosure state.

Depending on the symptom, investigation may use an oscilloscope, logic analyser, power analyser, thermal camera, debugger or protocol tools. Inspection may also examine solder joints, footprints, polarity, assembly substitutions and manufacturing defects.

The purpose is to separate schematic faults, layout faults, component problems, firmware behaviour and assembly defects.

Control the Revision

Once the reason is known, we identify the smallest number of modifications appropriate for this situation. All changes are registered in a record of revisions and connected to a verification stage.

The new revision may consist of the schematic diagrams, native PCB files, output documents for fabrication, the BOM modifications, generally accepted alternatives, assembly drawings, upgrades of firmware, and testing instructions.

Case Study: Recovering a Failed MSP430 Control-Panel Prototype

Recovering a Failed MSP430 Control-Panel Prototype
Phase 01 · Requirement

The Client and the Initial Requirement

One of the medium-sized producers of household appliances later turned to Adequate Infosoft for the creation of a touch control panel capable of withstanding high humidity levels to be installed in a premium washing machine.

The developed product is based on a Texas Instruments MSP430FR2633 chip featuring CapTIvate technology. Among other things, it included five capacitive buttons, a sliding control bar, status LEDs, a USB-to-serial converter, and a glass covering.

The company was required to substitute the unreliable mechanistic controls with an interface possessing high resistance to wet cleaning and damp working environment.

The design used four PCB layers. Capacitive electrodes and sensitive routing occupied the top layer, a continuous ground reference was placed internally, and control, communication and LED connections were routed separately. Hatched copper beneath the sensing regions helped manage parasitic capacitance.

Phase 02 · Failure

Failure Found During Board Bring-Up

The prototype that was first fully assembled passed the basic power and continuity tests but could not establish communications through the JTAG programming interface.

Instead of ordering another circuit board right away, the engineers went on to check the signals of the programming. The results obtained from an oscilloscope showed that the TCK clock line was constantly at 1.5 V instead of switching as expected at the logic level of 3.3 V.

The root cause was pin contention. The UART transmit and receive functions shared connections with the JTAG programming path, and the CP2102N USB-to-serial device was driving those lines while the programming probe was attached.

This was not a firmware defect or a defective microcontroller. It was an architectural conflict between two valid circuit functions.

Phase 03 · Re-spin

The Re-spin

The board was revised to bring in zero-ohm resistor jumpers that can break the circuit between the serial transceiver and the processor.

This has provided the development and production teams with the means of achieving the isolation of the connections for programming purposes.

Layout design also solved another key issue observed during testing: it caused noise in the capacitive sensing paths from the LED switching.

The routes were separated into analog and digital, LED signals were routed from the opposite side of the board, and crossings were done at 90 degrees.

After the revision, the team completed programming and used TI's CapTIvate tools to tune the touch thresholds through a 2 mm glass surface.

Phase 04 · Result

Verification and Result

The new prototype underwent evaluation in environmental, EMI and thermal areas of study. The usage of PWM in LED control has cut down unnecessary digital activity. Furthermore, thermal pathways have enabled the device to function without a heatsink.

According to the published case study, the prototype took around 12 weeks to be completed, and features IPX7 waterproof rating and less mechanical wear parts.

The important outcome was not simply that a second PCB worked. The failure was measured, traced to a specific conflict, corrected through a controlled hardware revision and verified in the real product environment.

Read the case study

Component Obsolescence Engineering

A product can remain commercially useful long after one of its components reaches end of life. Obsolescence engineering keeps that product manufacturable without introducing uncontrolled design changes.

We review the BOM for:

  • End-of-life and not-recommended-for-new-design parts
  • Manufacturer product-change notices
  • Single-source dependencies
  • Long or unstable lead times
  • Unauthorised sourcing risks
  • Parts with limited regional availability
  • Components approaching lifecycle transitions

Just because a substitute is ideal does not mean that it comes from the closest datasheet match. A substitute must be assessed based on electrical characteristics, physical dimensions, layout, switching characteristics, start-up characteristics, thermal characteristics, firmware support, and compliance impacts.

Form, Fit and Function Analysis

Replacement may be physically compatible but not function in the same way. For example, regulators can behave differently in transient response, sensors may need new register maps, and memory components can differ in time characterizations.

Modules using a wireless connection can impact the overall safety certification. We note whether the selected part is suitable as a plug-and-play replacement, just needs a BOM update, needs modification of the firmware, or requires a change in layout.

Where appropriate, we can create alternate footprints, configurable component options or approved substitute lists to reduce future supply-chain risk.

Evidence from Related Delivered Projects

Recovering a circuit board is a process that necessitates a deep understanding of the physical prototypes involved, adherence to compliance regulations, and several iterations of design. Some lesser-known cases undertaken by Adequate Infosoft illustrate these aspects.

Medical Wearable Compliance Remediation
Medical Wearable

Medical Wearable Compliance Remediation

The engineering team took a look at a wearable gadget manufactured using the STM32L496 and nRF52840 that required compliance with the IEC 60601 standard.

The design had several problems including isolation, electromagnetic compatibility issues, battery safety, and wireless coexistence.

The engineering team changed the architecture so that the power supply was isolated, they isolated the electrical systems, filtered the power supply made changes to the antenna system and routing of high-frequency signals. The results showed that the gadget that should have failed the electromagnetic compatibility test at 480 MHz passed the test and stopped sending the faulty Bluetooth packets.

Read the case study
AI Industrial Camera PCB Re-spins
Industrial Camera

AI Industrial Camera PCB Re-spins

For a North American industrial automation startup, Adequate Infosoft developed an eight-layer AI camera board integrating an NXP processor, image sensor, DDR3 memory, eMMC storage, Edge TPU and industrial communication.

The published case study records two layout re-spins during optimisation. A MIPI signal-integrity issue on the first revision was corrected by revising matched routing and shielding. Thermal throttling was addressed through improved heat transfer to the enclosure.

Read the case study
Wearable Device Using Different Components
Sports Wearable

Wearable Device Using Different Components

For a startup dealing with devices used in athletics, our team has created the circuit diagram, a four-layer printed circuit board (PCB), Gerber documentation, a BOM associated with sourcing as well as data on pick and place.

The availability of materials that are required was considered as an engineering aspect. The BOM that was created contained alternatives for the most important parts of the product including those related to sensing, energy and processing.

Read the case study
Existing STM32 LoRaWAN Device Optimisation
LoRaWAN

Existing STM32 LoRaWAN Device Optimisation

Adequate Infosoft also worked with an inherited STM32 LoRaWAN animal-farming device.

The project required a thorough evaluation of the current hardware and firmware, removal of unnecessary wake events, optimization of scheduling, addition of diagnostics, and readiness of the device for RF tests and pilot production.

The project is a good example of our capability to improve an existing embedded device without rejecting previous achievements.

Read the case study

What We Check Before Releasing a New Revision

A revised board should answer the original failure and remain suitable for manufacturing. Our review can cover:

  • Schematic and PCB consistency
  • Power-tree and sequencing behaviour
  • Decoupling and return paths
  • Clock, reset and boot configuration
  • Programming and debugging access
  • High-speed and differential routing
  • RF antenna placement and matching provisions
  • Thermal spreading and enclosure contact
  • Component lifecycle and sourcing
  • Footprints, polarity and assembly orientation
  • DFM, DFT and test-point access
  • Fabricator and assembly-house design rules

The verification plan is tied to the change list. If the re-spin modifies a power supply, we test startup, shutdown, peak load and fault behaviour. If it changes a communication interface, we exercise that interface under realistic traffic and environmental conditions.

Deliverables and Ownership of Design

The scope of the deliverables varies depending on the project. Some of the components include:

  • Finalized schematic and printed circuit board (PCB) files
  • Documentation of all changes discussed and covered in the project
  • Investigation report of the main cause of the problem established through the project
  • Updated bill of materials and approved substitutions
  • Output files for the creation of printed circuit boards
  • Finished drilling, placing and assembly data
  • A new version of a 3D board model
  • Test protocol for the prototype created during the project
  • Changes of the firmware and notes for the release
  • Instructions for the production
  • Requirements for testing the board in factory conditions

Ownership of the files, their licensing, and third-party dependencies are specified in the project agreement.

Bring Your Existing PCB Back to Production

It's not always the case that a failed prototype or an outdated component would require a complete redo of the process. It's often possible to keep some parts of the design and just work on the broken elements.

Share your PCB design and layout, schematic, parts list, firmware, tests, and assembled boards with Adequate Infosoft. We can evaluate your design and propose an optimal way to fix issues.

Frequently Asked Questions

Can you redesign a board if we only have Gerber files?

Maybe. Gerber files will allow reconstructing the circuit board, but they do not have all required schematic information. We need to evaluate these files along with actual boards and documentation to evaluate the effort required for recovery.

Should we rework the existing PCB or order a re-spin?

Rework is valuable for confirming a suspected solution. A re-spin is normally appropriate when the correction must become repeatable, manufacturable and suitable for production.

Can you replace an obsolete microcontroller?

Yes, but an MCU replacement may affect the footprint, peripherals, clocking, memory, firmware and programming process. We assess hardware and software migration together.

How do you reduce the risk of another failed revision?

We attribute a particular reason and a test to every design change. All reviews, DFM checks, prototype launches, and revision logs help to avoid any surprises before the mass production stage.

Editorial Sources

Adequate Infosoft

Capacitive Touch Control Panel Development Using TI MSP430

Read source
Adequate Infosoft

PCB Design, Layout and Fabrication Services

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IPC

Electronics Standards and Qualification Resources

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Omkar Prayag
Omkar Prayag
IPC CID+ Certified Hardware Designer
High-Speed PCB Layout Design | Signal Integrity (SI) & Power Integrity (PI) Analysis | Fault-Tolerant System Design | Multi-Layer PCB Development | Hardware Architecture & Circuit Design | Prototype to Production Engineering
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