Rework and Repair of Electronic Boards under IPC-7711/7721
We repair electronic boards that are no longer functional: incorrectly mounted components, improper soldering, damaged traces, or engineering changes to already assembled products. We work under IPC-7711/7721 and we agreed with you the class (1, 2 or 3) before we begin.
It's the service you resort to when the alternative is to dump the lot. In our history there are more than 21,000 cards seized for Tier-1 automotive and global EMS suppliers with operations in Mexico, and a multi-month operation within a customer's plant.
Rework, repair, and modification are not the same thing
The standard separates them, and the distinction determines whether the card still conforms to the original design:
- Rework (IPC-7711). Return the card to what the design already required: remove and replace a component, correct a solder joint, reorient a piece. The design does not change.
- Repair (IPC-7721). To repair something that was damaged and that the design didn't allow for: a lifted trace, a detached pad, a broken metal hole. The board works again, but There is one element left that was not in the design, And that is documented.
- Modification. An engineering change on a product that has already been assembled. The design does change., By the way.
Confusing them is what makes a repaired card be accepted as if it were intact. We specify which of the three was used on each piece.
What do we do?
- Removal and replacement of components, SMD and insert, with thermal profile control to avoid exceeding the heat budget of neighboring parts.
- Repair of tracks, pads and metal holes, executed according to specifications and work orders. It's not improvised: the method and criteria are defined first, and then the work is carried out.
- Installation of jumpers and engineering changes (ECO) on the already assembled PCBA.
- Welding correction out of line.
- Selective desoldering when the component cannot withstand generalized heat.
- Removal of conformal coating in order to intervene, and their reapplication Afterwards. Removing the coating without damaging laminate, components, or neighboring tracks is one of the difficult things about the job.
- Inspection of the result against the agreed class criterion.
He BGA re-balling is not our specialty.. If your case requires it, let us know and we'll evaluate it, but we prefer to tell you sooner rather than later.
When rework requires reconditioning the material afterward—re-taping, repackaging, or sealing it—we do that too: see taping of components.
The three CPI classes, and why they are agreed upon sooner
IPC defines three product classes, and the acceptance criteria change with each one:
| Class | What product is it? | Acceptance criteria |
|---|---|---|
| Class 1 | General electronic product | What matters is that it works. |
| Class 2 | Dedicated service product | Sustained performance and a long lifespan are expected; aesthetic, but not functional, imperfections are tolerated. |
| Class 3 | High performance | A product that cannot fail and operates in a demanding environment. The criteria are the strictest. |
The three of us work together. And it's agreed at the beginning, not at the end: reworking class 3 with class 1 criteria is cheap until the part comes back.
The step that ruins a hastily done rework
A circuit board that has been in storage absorbs moisture. If it is brought to reflow temperature without being dried first, that moisture turns into vapor inside the laminate and component encapsulation.
The result is internal delamination and invisible microcracksThe card comes out of rework seemingly fine, passes visual inspection, and fails months later in the field.
That's why the rework begins before the soldering iron. Assemblies sensitive to humidity go through... Baked according to IPC/JEDEC J-STD-033 before intervention. We have the oven and the process: it's the same line with which we give baking and drying.
A rework done without that step is cheaper and takes less time.
We'll come to your plant, and we can do it properly.
Much of this work cannot be moved. The batch is stuck on your line, the product cannot leave your facilities, or there simply isn't enough time to ship it twice.
We go to the client's plant when the project requires it. We spent several months inside a Tier-1 automotive plant recovering circuit boards that their local repairers hadn't been able to fix. It wasn't volume; it was complexity, and it took the skill and expertise to intervene without damaging what was already working properly.
And there's one detail that in Mexico determines whether that operation is viable: We have a current REPSE registration.
Since the 2021 reform, any company that provides specialized services with its own staff within the facilities of a third party must be registered in the Registry of Specialized Service Providers or Specialized Works from the Ministry of Labor. And it's not just a procedure for the supplier: The contracting party can only deduct the ISR (Income Tax) and claim the VAT credit for those services if the provider has a valid registration.
In other words, hiring someone without REPSE certification to work at your plant will cost you the tax deductibility of the expense. It's one of the first things a serious purchasing department checks, and one that most suppliers can't prove.
How do we do it?
1. Scope and class
The defect is defined, including the number of affected parts, and whether it requires rework, repair, or modification. The IPC class and acceptance criteria for judging the result are agreed upon. If the defect has not yet been characterized, it is advisable to first consult our guide on [specific instructions/guide]. failure analysis.
2. Pre-baking when applicable
Drying according to J-STD-033 before applying heat to a moisture-sensitive assembly is the most frequently skipped and most expensive step.
3. Removal of coating, if any
When the card has conformal coating, it is removed only in the area to be worked on, without damaging laminate, components or neighboring tracks.
4. Intervention
Using the appropriate tool for each case and monitoring the thermal profile. When repairing tracks, pads, and holes, work is carried out according to the specifications and work order defined in step 1.
5. Reapplication of coating
When the card had it, the conformal coating was reapplied to the treated area.
6. Inspection and registration
Verification against the agreed class criterion, combining automated inspection with Eyve, Our AI-powered vision system and visual verification are used. The standard requires that the repair be documented: a record is kept of what was done to each part and under what classification.
Acceptance criteria
Electronics is a highly regulated industry, and in rework that matters more than in any other process: the difference between a recovered card and a compromised card lies in a written criterion.
We work under IPC-7711/7721, with IPC-A-610 as a reference for visual acceptance and J-STD-001 for welding. Each operation is performed under the applicable standard —IPC, JEDEC, EIA— and we have Certified personnel and internal IPC certifiers: the training and verification of the criteria are supported at home.
We work in our own plant, in an ESD area with environmental control, and at the client's plant when the project requires it.
Frequently Asked Questions
What is the difference between rework and repair?
Rework restores the card to what the design originally required; repair restores something damaged that the design didn't include, and leaves an element that wasn't in the original. The standard distinguishes between them, and we specify which was done on each piece.
Do they do BGA re-balling?
It's not our specialty. We can assess the case, but if your primary need is reballing, it's best to mention it from the outset.
Do you repair metal tracks and boreholes?
Yes, against specifications and work orders. The method and criteria are defined before intervening, not on the fly.
Can they make engineering changes to a card that's already assembled?
Yes. Installation of jumpers and ECO on the PCBA. It's documented as a modification, which is what it is: a deliberate change to the design.
Are they going to our plant?
Yes, and with current REPSE registration, which is what allows the contractor to deduct the ISR and credit the VAT for a specialized service provided within its facilities.
What type of CPI do they use?
All three, from class 1 to class 3. It is agreed at the beginning of the work.
Do I need to bake the card first?
If the assembly was stored and is sensitive to humidity, then yes. Without that step, the heat from rework turns the moisture into steam and delaminates the laminate. It's damage that isn't visible.
Do they work with small batches?
Yes. A large part of what arrives are held-up batches, not production.
Do you have a batch on hold?
Send us photos of the defect, the number of pieces, and, if you have them, the acceptance criteria by which it should be judged. With that information, we can tell you if it's a rework, repair, or modification, and what can be salvaged. Contact us.
If the work has to be done inside your plant, then yes: we'll go, and with a valid REPSE permit.