PCB repair and rework: diagnosis, repair and design modifications
Faults found, boards repaired to IPC-7711/7721, changes implemented under change control and every board retested before it returns.
In short: Comtec Labs repairs and modifies printed circuit boards in Vaasa, Finland. Our engineers diagnose the fault, repair the board to the IPC-7711/7721 rework procedures and retest it, and the root cause is fed back into the process and, where relevant, into the design. Design updates on built boards run as an engineering change order with your approval, and every rework is logged per board with the operator and the procedure used.
Who this service is for
Repair and modification are usually needed at moments when time matters: a batch has a fault, a product in the field needs an update, or a design change has to reach boards that are already built. Typical situations are:
- correcting manufacturing issues found in test or inspection, so the boards can still be delivered instead of scrapped
- implementing a design update, such as a changed component value, a replaced part or a revised circuit, on boards that are already assembled
- improving a product in the field, so its electronics last longer and the investment in it is protected
- product teams that need a faulty prototype or pilot board analysed to learn whether the cause is the process, a component or the design
We also repair boards built by other manufacturers.
How a repair or modification runs
- Fault description. Tell us the symptom, the board revision and serial numbers, and any test results you already have. For a modification, send the change description or the updated schematic and BOM.
- Diagnosis. Engineers locate the fault using visual and automated optical inspection, X-ray on area-array packages and electrical or functional test.
- Change control. When the fix changes the design, it runs as an engineering change order with your approval at each step and an updated BOM revision.
- Rework. The board is repaired to the IPC-7711/7721 procedures in an ESD-protected environment. Where a board is coated, the coating is removed locally, the repair made and the area recoated.
- Verification. The repaired board is inspected and retested before it returns to you or to the production flow.
- Record and feedback. The rework is logged against the board with the operator and the procedure used, and the root cause is fed back into the process and, when relevant, into your design.
What we repair and modify
| Type of work | What it covers |
|---|---|
| Fault diagnosis | Locating the cause of a failure with inspection and electrical or functional test |
| Repair | Rework of solder joints and replacement of faulty components to IPC-7711/7721 |
| Design modifications | Design updates on built boards, run as an engineering change order with your approval |
| Manufacturing corrections | Correcting issues found in inspection or test so the batch can be delivered |
| Coated boards | Local coating removal, repair and recoating |
| BGA and QFN | Rework and reballing on a BGA/QFN rework station, checked with X-ray |
| Verification | AOI, X-ray on area-array packages and functional test with the same test used in production |
Turnaround
How long a repair takes depends mostly on two things: how quickly the fault can be located, and whether replacement components are in stock. A modification that only changes a component value is fast; one that needs new parts waits for those parts. Repairs of boards we build in production are handled within the same flow as the batch, so a failed board is analysed, repaired and retested before the batch ships.
After we receive a board, it is assessed within 1 working day, and a typical repair takes 2–5 working days.
Environment and equipment
Repairs are done in the same ESD-protected production environment in Vaasa where we assemble, inspect, test and coat boards. That gives a repair access to the same automated optical inspection, the same functional test fixtures, which are built in-house, and the same automated selective coating line used in series production.
Area-array parts are reworked on a BGA/QFN rework station and checked with in-house X-ray.
See the full equipment list, capabilities and lead times
Quality and standards
- Rework and repair follow the IPC-7711/7721 procedures.
- Every rework is logged per board with the operator and the procedure used, so the repair history is part of the traceability record.
- Where serial traceability is configured, the rework history is linked to the individual serial number together with its test results.
- Design changes are run as an engineering change order with your approval at each step.
- Root causes are fed back into the process and, when relevant, into the design, so the same fault is not repaired twice.
Repaired work carries a 12-month warranty.
Repairing coated boards
Conformal coating does not make a board unrepairable, but the choice of coating decides how easy the repair is. As a general industry rule, acrylic coatings are the easiest to rework: they can be removed locally with solvent or heat, the repair made and the area recoated. Urethane and silicone coatings are harder to remove, so products that use them should be designed for fewer field repairs. If you expect boards to come back for service, discuss it at design review, when the coating type and masking are agreed.
Frequently asked questions
Can a coated PCB be repaired?
Yes. The coating is removed locally, the repair is made and the area is recoated. Acrylic coatings are the easiest to rework; urethane and silicone are harder to remove.
Which standard do you follow for PCB rework?
Repairs and rework follow the IPC-7711/7721 procedures, and each rework is logged per board with the operator and the procedure used.
Can you implement a design change on boards that are already built?
Yes. The change runs as an engineering change order with your approval at each step, the boards are reworked and retested, and the BOM revision is updated so future batches are built to the new design.
Do you find out why the board failed?
Yes. A failed board is analysed before it is repaired, and the root cause is fed back into the process and, when relevant, into the design.
Is the repair recorded?
Yes. Every rework is logged against the board with the operator and procedure, and with serial traceability it is linked to the serial number and its test results.
Related reading
- PCB Testing Methods Explained: AOI, X-ray, Flying Probe, ICT and Functional Test
- What Traceability Should a PCB Assembly Partner Provide? Lot, Serial, Process and Test Records
- When Does a PCB Need Conformal Coating? A Decision Guide
- The Most Expensive PCB Problems Are Found Too Late
Related services
- PCB functional testing
- PCB assembly
- Conformal coating service
- PCB design services
- Electronic component sourcing
Ask about a repair or modification
Describe the fault or the change you need, with the board revision, the quantity and any test results. Our engineers come back to you with the next steps.
