The Repair LibraryRead · Learn · Master

When to Reball vs. Replace

The hands-on volume opens where the case file arrives, with the decision that governs everything the reballing chapter teaches: whether this package should be rebuilt at all. The assessment chapter drew the envelope — reballing renews ball metallurgy over intact pads on living silicon — and this section refines that line into working preconditions: the board-side gate the case file must have cleared, the evidence that the silicon is worth rebuilding onto, and the package classes whose underfill or stacked construction move them off the reballing bench entirely. Then it adds the two budget lines the envelope never priced. The first is the package heat lifetime: every reflow spends a package — intermetallics grow, warpage accumulates, and package-internal joints age — and a full reball round trip costs several exposures, so a package that has already survived one rework carries a different arithmetic than a factory-fresh one. The second is moisture: packages absorb it in storage, reflow vaporizes it, and the popcorning the hot-air chapters warned about is how a skipped bake destroys a package the decision had approved — moisture sensitivity and the bake it demands are part of every honest reball plan. Alongside the budgets sits the question that makes some reballs worth doing on healthy packages: alloy conversion, the deliberate rebuild in a different ball chemistry — most often leaded spheres on a lead-free package — bought for gentler future rework on fragile boards, priced as the trade it is rather than the upgrade it is not. And against all of it stands replacement: new parts when the market offers them, donor packages that arrive with unknown histories and usually need their own reball anyway, and the three-way decision — reball, replace, or the honest neither — that this section teaches the bench to make on evidence and write into a quote.

AdvancedLow Risk23 min read

What You Will Learn

  • You will learn reballing's preconditions — intact pads, living silicon, and a package class the bench can actually rebuild.
  • You will learn the package heat lifetime — how reflow exposures accumulate and what a reball round trip costs.
  • You will learn moisture sensitivity — why stored and harvested packages bake before any reflow, and what popcorning costs when they do not.
  • You will learn alloy conversion — the deliberate rebuild in a different chemistry, and when it is the reball's whole point.
  • You will learn the three-way decision — reball, replace, or neither — priced on evidence, budgets, and the parts market.

What You Will Be Able To Do

  • You will be able to gate a case file through reballing's preconditions and write the verdicts.
  • You will be able to budget a package's heat lifetime and moisture state, bake included.
  • You will be able to judge when alloy conversion justifies reballing a healthy package.
  • You will be able to weigh new parts and donor packages against the rebuild honestly.
  • You will be able to run the three-way decision and write the quote it produces.

Required Tools

  • The Chapter 3 case files — this decision consumes evidence, and the inspection chapter produced it
  • Parts-market sources — new-part and donor-board pricing is looked up live, never assumed
  • The donor bin's packages with their histories where known — heat budgets need biographies
  • The notebook — this section builds the precondition gate, the budget worksheet, and the three-way quote
  • No hot tools — the chapter's heat starts next section, after this one decides where it should land

When NOT to Attempt This

Do not attempt this section if any of the following apply to you:

  • You are not comfortable working with small surface-mount components.
  • You have not completed the prerequisite sections for this skill.
  • You do not have the required tools in working condition.

Section Overview

The hands-on volume opens with its governing decision: whether this package should be rebuilt at all (bga-repairability-assessment). The preconditions gate first. Pads intact, silicon alive, package class rebuildable — three gates, each demanding the case file's evidence (thermal-profiling-for-bga-diagnosis). The package heat lifetime budgets the rebuild. Every reflow spends the package, and a reball round trip costs several exposures — biographies matter (bga-ball-composition-and-alloys). Moisture is the second budget line. The moisture sensitivity level names what storage absorbs and reflow vaporizes — the bake prevents the popcorning the hot-air chapters warned about (common-hot-air-mistakes). Alloy conversion makes some reballs worth doing on healthy packages. A different chemistry bought deliberately — gentler future rework, priced as a trade. And the decision is three-way. Reball, replace — knowing donors carry unknown biographies — or the honest neither, written into a quote. Gates, budgets, conversion, market — the decision entire.

Why This Matters

Reballing is hours of Professional-grade bench work, and this section is what keeps those hours off packages that should never receive them (bga-repairability-assessment). This matters because the preconditions prevent the classic waste: a beautiful reball onto cratered pads is fresh spheres joined to nothing, and a rebuilt field under dead silicon is craftsmanship on a corpse — the gates run before the heat because afterward is too late (thermal-profiling-for-bga-diagnosis). This matters because the heat budget is invisible until it is spent: a package that survived one careless rework may fail during a flawless second one — intermetallics and internal aging accumulate silently, and the biography question separates the rebuild candidate from the liability (bga-ball-composition-and-alloys). It matters because moisture destroys approved plans: the harvested donor that sat in a drawer for a year carries absorbed moisture that reflow will vaporize — popcorning is the failure, the bake is the prevention, and the plan that skips the bake gambled the package on a shortcut (common-hot-air-mistakes). It matters because conversion reframes the service: fragile boards facing repeated rework are sometimes best served by a leaded rebuild — the reball as strategy rather than repair — and the bench that can explain the trade sells honest work. And it matters because the market anchors everything: a new part in stock at a fair price beats most rebuilds, a donor package usually needs its own reball anyway, and the three-way quote — including neither — is the assessment discipline arriving at its first hands-on decision. Decide before stripping — the chapter's remaining sections all assume this one said yes.

Required Prerequisites

  • Nothing consumed — the section spends judgment on evidence already gathered (thermal-profiling-for-bga-diagnosis)
  • A notebook page for the precondition gate — to write the three gates and their evidence lines once, reusably (bga-repairability-assessment)
  • A page for the package budget worksheet — to tally exposures spent and planned, with the moisture line included (common-hot-air-mistakes)
  • A page for the three-way quote templates — to draft reball, replace, and neither in calm language before a customer waits on any of them (bga-ball-composition-and-alloys)
  • The Chapter 3 practice case files — to gate real assembled evidence instead of hypotheticals (thermal-profiling-for-bga-diagnosis)
  • The donor bin's packages, especially any with known rework history — to practice biographies on parts whose past is documented (bga-ball-composition-and-alloys)
  • A live parts search on two real packages — to anchor decisions in today's market rather than remembered prices (bga-repairability-assessment)
  • One long-stored or harvested package — to hold the moisture question in hand while writing its bake line (common-hot-air-mistakes)
  • The bench camera — to file gates, budgets, and quotes beside the case files they decide

Real-World Applications

The decision pays for the chapter ahead by refusing the wrong patients and pricing the right ones. A bench holding a console APU case file — cycling toggle logged, meters convicting the die-shadow ring, pads evidenced intact runs the gates and says yes: the fault is ball metallurgy, the silicon answered the meters, and the reball quote goes out with the budget's exposure count and bake line written in (thermal-profiling-for-bga-diagnosis). A shop asked to rebuild a twice-reworked laptop GPU reads the biography first: two prior hot-air sessions already spent the package's margins, and the honest quote offers replacement — or the bounded neither — instead of a third round trip the heat lifetime cannot fund (bga-ball-composition-and-alloys). A restorer keeping a vintage arcade cabinet's fragile board alive chooses conversion: the original package is healthy, but a leaded rebuild buys every future rework thirty gentler degrees — the reball as strategy, quoted as the trade it is (bga-repairability-assessment). And a technician offered a cheap donor package for a dead controller prices the donor honestly: unknown biography, a year in someone's drawer — its own bake, its own reball, and its own risk — and sometimes the new part at twice the price is half the cost (common-hot-air-mistakes). The confusions this prevents: a flawless rebuild onto pads nobody gated, a third rework funded by a budget nobody counted, a drawer-stored donor popcorned by a skipped bake, and a conversion sold as an upgrade instead of the trade it is.

Common Challenges

  • The case file tempts shortcuts. A strong toggle signature makes the gates feel redundant — but the toggle convicted the fault, not the pads or the silicon; the gates ask different questions than the diagnosis did (thermal-profiling-for-bga-diagnosis).
  • Biographies are often unwritten. Most packages arrive with no rework history — the discipline is inference and honesty: solder texture, flux staining, and the board's own record hint at past heat, and unknown history prices conservatively (bga-ball-composition-and-alloys).
  • The bake feels like lost time. Hours in an oven before any visible work — until the alternative is a popcorned package and a restarted job; the bake is the cheapest insurance the chapter sells (common-hot-air-mistakes).

Safety Notes

Risk Level: Low. This section decides — the chapter's heat begins next section, and nothing here licenses it early.

Professional Tips Before Starting

  • Gate in writing, every time. Three lines — pads, silicon, class — each with its evidence cited — the written gate catches the case the confident memory waves through (thermal-profiling-for-bga-diagnosis).
  • Start the biography at intake. Ask the customer what work the board has seen; log what the solder and flux staining suggest — the budget's hardest line is easiest to fill at the start (bga-ball-composition-and-alloys).
  • Bake by default on unknowns. A package whose storage history is unknown is a package that needs the oven — the default costs hours; the exception costs packages (common-hot-air-mistakes).

The Decision — Gates, Budgets, Conversion, Market

Recap and Frame

The theory volume ended with a case file; the hands-on volume opens by consuming it (thermal-profiling-for-bga-diagnosis). The envelope drew the line already. Reballing renews ball metallurgy over intact pads on living silicon — the assessment section's sentence, now promoted from principle to procedure (bga-repairability-assessment). The metallurgy chapter supplied the chemistry. Ball alloys, the silver trade, the mixing rule's binary — the facts that make conversion a real option and chemistry a real decision (bga-ball-composition-and-alloys). The hot-air fundamentals supplied the warning. Popcorning — moisture flashing to steam inside a heated package — was Volume 3's lesson on other parts; the BGA bench inherits it at higher stakes, because the packages are bigger, costlier, and often irreplaceable (common-hot-air-mistakes). What is new is the package as patient. The board had the case file; now the package itself gets examined — its pads' evidence, its silicon's vital signs, its biography, its moisture state — before anyone commits to rebuilding it. And the section's order is the decision's order: gates first, budgets second, the conversion question, then the market and the three-way call. Hold the frame — evidence in, decision out, heat not yet — and the chapter opens properly.

The Gates — What a Reball Requires Before It Begins

Reballing renews exactly one thing, so three gates ask about everything else (bga-repairability-assessment). The pad gate asks the board-side question. Fresh spheres on cratered pads are joints to nothing — the case file's evidence on pad condition passes or fails this gate, and where the file is silent, the gate stays closed until the removal section's direct inspection can answer: assumed-intact is not a gate verdict — and the package's own pads face their inspection after the strip, at the cleaning section's gate. The silicon gate asks for vital signs. A package worth rebuilding is a package the case file caught alive — meters answering at its nets, signatures consistent with joint failure rather than die death — and the subtractive logic runs in reverse: a field convicted of cracks with silicon that responded is the reball's ideal patient; a package that stayed silent through every instrument may be dead above the balls, and rebuilding under a corpse wastes the chapter (thermal-profiling-for-bga-diagnosis). The class gate asks what the bench can rebuild. A plain overmolded BGA at reachable pitch reballs; an underfilled package must survive its removal first and often does not; a stacked package is two ball fields and a ladder rung this chapter does not teach — the landscape section's reads arrive here as verdicts (bga-ball-composition-and-alloys). Each gate cites evidence. Three written lines — pads, silicon, class — each pointing at the case file's page or naming the inspection that must still happen; the gate that cannot cite is the gate that is not passed (common-hot-air-mistakes). Board-side, die-side, package class — the gates entire. The gates ask what reballing cannot fix — pass all three before counting a single sphere.

The Budgets — Heat Lifetime and the Moisture Line

Two budget lines price the rebuild before the market gets a word, and both live in the package rather than the wallet (bga-ball-composition-and-alloys). Every reflow spends the package. Intermetallic layers grow with each excursion, warpage accumulates, and a flip-chip package's internal bumps age alongside its balls — the damage is cumulative and mostly invisible, which is why it is budgeted rather than inspected. A reball round trip costs several exposures. Removal from the board, the reball's own attach reflow, reinstallation — three heats minimum, and a package that already survived a prior rework is asking its aged interconnects to fund the trip: the biography decides whether the funds exist (thermal-profiling-for-bga-diagnosis). Biographies are read as much as told. Customer history when it exists; solder texture, flux staining, and pad wear when it does not — and the unknown biography prices conservatively, because the budget's worst error is spending margins that were already gone (bga-repairability-assessment). The moisture line is the second budget. Plastic packages absorb ambient moisture in storage — the moisture sensitivity discipline the assembly world runs on — and reflow vaporizes what storage absorbed: the steam delaminates and cracks from inside, the popcorning failure, worst exactly on the large-bodied packages this chapter rebuilds (common-hot-air-mistakes). The bake is the answer, and it is planned, not remembered. Hours at controlled low heat dry the package before any reflow touches it — harvested donors, drawer-stored spares, and long-idle boards all bake by default, and the bake's hours belong in the quote. Exposures counted, biography read, moisture dried — the budgets entire. The package funds every reball out of its own remaining life — count the account before writing the check.

The Conversion — When the Rebuild Is the Point

One reball class operates on healthy packages, and it exists because chemistry is a choice (bga-ball-composition-and-alloys). Alloy conversion rebuilds on purpose. The metallurgy chapter's binary rule offered two honest paths, and conversion is the second: strip the lead-free field entirely and rebuild in leaded spheres — known chemistry, sharp eutectic behavior, and every future reflow on this package thirty degrees gentler. The candidates are strategic. Fragile or irreplaceable boards facing a prognosis of repeated rework; vintage restorations where the surrounding board was built for leaded temperatures; packages whose neighbors cannot survive lead-free rework heat again — conversion serves the board's future, not the package's present. The trade is named, never hidden. A converted package leaves the board's original chemistry and, where regulations govern commercial work, its compliance status — the record logs the conversion, the quote explains it, and the customer chooses it knowingly: conversion is a trade with a purpose, not an upgrade (bga-repairability-assessment). The budgets still apply. A conversion spends the same round-trip exposures and demands the same bake — healthy silicon does not exempt the package from its own account (common-hot-air-mistakes). The gates still apply too. Conversion on damaged pads or dying silicon is the same waste wearing better intentions — the decision's structure does not bend for strategy (thermal-profiling-for-bga-diagnosis). Deliberate, strategic, named, and still gated — the conversion entire. Conversion answers a prognosis, not a diagnosis — reach for it when the board's future, not its present, is the patient.

The Market and the Call — Reball, Replace, or Neither

The decision's last input is the market, and its output is one of three honest sentences (bga-repairability-assessment). New parts anchor hard. A current package in stock at a fair price beats most rebuilds on every axis — fresh biography, no bake debt, factory balls — and the live search is part of the decision, because remembered prices and vanished stock have priced many rebuilds that should never have happened. Donor packages are priced honestly. A harvested part arrives with an unknown biography, a storage history that demands the default bake, and — because harvesting is a removal — at least one heat exposure already spent plus its own reball still to fund: the cheap donor is frequently the expensive option wearing a low sticker (bga-ball-composition-and-alloys). The reball case closes on evidence. Ball-metallurgy fault in the file, three gates cited, budget funded, market unhelpful or the package irreplaceable — that conjunction is the reball's honest yes, and the chapter's remaining sections exist for it (thermal-profiling-for-bga-diagnosis). The neither is a professional verdict. Gates failed and market empty, budget spent and data already rescued — some case files end in a bounded no, and the quote that says so with reasons outranks the heroic attempt that converts a diagnosis into a loss (common-hot-air-mistakes). The quote carries the decision's anatomy. Which path, the gate verdicts, the exposure count and bake line, the stated success fraction, the market anchor — the assessment's quote discipline, now with reballing's own line items. Anchored, honest, three-way, written — the call entire. The chapter ahead teaches the yes — this section's job was making sure the yes is earned.

Common Mistakes

  • Reballing past a silent gate. Pads assumed intact because the case file never mentioned them — silence is not evidence; the gate waits for the removal's direct look or stays closed (thermal-profiling-for-bga-diagnosis).
  • Funding a third rework from an empty account. A twice-reworked package approved because the last rework 'went fine' — the budget counts exposures, not outcomes, and aged interconnects fail during flawless work (bga-ball-composition-and-alloys).
  • Skipping the bake on a deadline. A drawer-stored donor straight to reflow because the oven costs hours — popcorning costs the package and the restart; the bake is the fast path wearing a slow face (common-hot-air-mistakes).
  • Selling conversion as improvement. 'Upgraded to leaded balls' on an invoice — conversion is a trade with named costs; the record and the customer both deserve the honest framing (bga-repairability-assessment).
  • Deciding from remembered prices. A rebuild quoted because 'those parts are unobtainable' without today's search — markets move; the live anchor is part of the decision, every time.

Troubleshooting Guidance

The decision troubleshoots its own inputs: ungated, unfunded, unanchored. If a gate cannot cite evidence: route the question, not the job — the pad gate waits for removal's inspection, the silicon gate for one more meter session; a gate pending is a decision paused, never a decision assumed (thermal-profiling-for-bga-diagnosis). If a biography is blank: read the package — reflowed texture on factory balls, flux staining under the edge, wear on the board's fasteners — and where the reading stays blank, price as previously-reworked, because the conservative error costs margin and the optimistic one costs the package (bga-ball-composition-and-alloys). If the moisture state is unknown: it is not unknown — it is wet; the default bake exists precisely so this question never blocks a decision (common-hot-air-mistakes). If the market search returns chaos: anchor on what is orderable today at a price a customer would pay — grey-market listings that may never ship are not anchors, and the quote can name the uncertainty (bga-repairability-assessment). If the three-way call will not settle: write all three quotes anyway — the act of pricing each path usually reveals which one the evidence was already pointing at, and the customer sometimes settles what the bench could not. The throughline: decision disputes resolve by naming the missing input — gate, budget, or anchor — and going to get it.

Verification & Testing Methods

Confirm the decision before the chapter's heat begins:

  • [ ] I can gate a case file — pads, silicon, package class — with each verdict citing its evidence or naming the inspection still owed.
  • [ ] I can budget a package heat lifetime — exposures spent and planned — and read a biography from solder, flux, and history.
  • [ ] I can write the moisture line — moisture sensitivity level logic, the default bake, and its hours in the quote.
  • [ ] I can judge an alloy conversion — the prognosis it answers, the trade it costs, and the record it demands.
  • [ ] I can run the three-way call against a live market anchor and write the quote each path produces, including neither.

Then try the practice exercises below — desk and judgment work only; scenarios differ from the quiz.

Practice Exercises

  1. Gate one case file (5 minutes, a Chapter 3 practice file, notebook). Run the three gates in writing — pads, silicon, package class — citing the file's evidence line for each verdict or naming the inspection still owed, and close with the gate summary the quote will carry (thermal-profiling-for-bga-diagnosis).
  2. Budget two biographies (5 minutes, two donor packages, notebook). For one factory-fresh-looking package and one with visible rework history: tally exposures already spent as the evidence suggests, add the round trip's three, write the moisture line — storage history, default bake, hours — and mark which budget still funds a reball (bga-ball-composition-and-alloys).
  3. Write the conversion memo (5 minutes, desk). For a fragile vintage board facing repeated future rework: whether leaded conversion serves the prognosis, the trade it costs in chemistry and record, the bake and exposure lines it still pays, and the customer sentence that names it a trade rather than an upgrade (bga-repairability-assessment).
  4. Price the three-way call (5 minutes, desk, live parts search). For one real donor-bin package: run today's market search, then write all three quotes — reball with gates and budget lines, replace with the anchor and donor caveats, and the bounded neither — and mark which one the evidence was pointing at all along (common-hot-air-mistakes).

These core steps — the gate, the budgets, the conversion memo, and the three-way pricing — are tested in the Chapter Quiz at the end of this chapter, where a score of 80% is required to continue.

Key Takeaways

  • Reballing's three gates ask what it cannot fix — pads intact, silicon alive, package class rebuildable — and every verdict cites evidence or names the inspection still owed (thermal-profiling-for-bga-diagnosis).
  • The package heat lifetime funds every rebuild — exposures accumulate invisibly, a round trip costs several, and biographies are read from solder and staining when nobody wrote them down (bga-ball-composition-and-alloys).
  • The moisture sensitivity level line is a budget entry: stored and harvested packages bake by default, because popcorning is how a skipped bake destroys an approved plan (common-hot-air-mistakes).
  • Alloy conversion rebuilds healthy packages on purpose — a prognosis answered with gentler chemistry, priced and recorded as the trade it is (bga-repairability-assessment).
  • The call is three-way against a live market — reball on evidence, replace on the anchor with donors priced honestly, or the professional neither — and the quote carries the decision's whole anatomy.

Skills Learned

  • You can now gate a case file with cited evidence before any heat is scheduled.
  • You can now budget exposures and read package biographies conservatively.
  • You can now plan the moisture line and default the bake on unknowns.
  • You can now judge and honestly frame an alloy conversion.
  • You can now run the three-way decision against today's market and write its quotes.

Glossary Additions

  • package heat lifetime — the cumulative budget of reflow exposures a package can fund before its own construction becomes the failure: every excursion to solder temperatures grows intermetallic layers, accumulates warpage, and ages a flip-chip package's internal bumps — damage that is cumulative and mostly invisible, so it is budgeted rather than inspected. A reball round trip costs several exposures — removal, the reball's own attach reflow, reinstallation — and a package that has already survived prior rework is asking aged interconnects to fund the trip, which is why biographies decide budgets: customer history where it exists, the package's own tells — reflowed ball texture, flux staining, pad wear — where it does not, and conservative pricing on unknowns, because the budget's worst error is spending margins that were already gone.
  • moisture sensitivity level — the assembly world's grading of how readily a plastic package absorbs ambient moisture and how long it may sit exposed before reflow becomes dangerous: absorbed moisture vaporizes at solder temperatures, and the internal steam delaminates and cracks the package from inside — the popcorning failure, worst on the large-bodied parts the reballing bench handles. The repair bench inherits the discipline without the factory's sealed bags and floor-life clocks, so its rule is the default bake: harvested donors, drawer-stored spares, and long-idle boards dry at controlled heat — typically 125 °C, from hours to a day or more by package thickness — before any reflow touches them, the bake's hours belong in the quote, and an unknown storage history is treated as wet — because the question the factory answers with logging, the bench answers with the oven.
  • alloy conversion — the deliberate reball of a healthy package into a different ball chemistry — most often leaded spheres replacing a lead-free field — bought for the board's future rather than the package's present: a converted package makes every subsequent reflow on that board roughly thirty degrees gentler, which serves fragile or irreplaceable boards facing repeated rework, vintage restorations built for leaded temperatures, and neighborhoods that cannot survive lead-free heat again. Conversion is the metallurgy chapter's binary rule operationalized — strip fully, rebuild in one known chemistry — and it is a trade, not an upgrade: the board's original chemistry and, where regulations govern, its compliance status are named in the record and the quote, the customer chooses knowingly, and the gates and budgets of any reball still apply, because strategy exempts a package from nothing.

Suggested Next Sections

Must read next:

  • Ball Removal Techniques — Section 4.2 begins the approved rebuild: taking the old alloy off the package with wick and low-temperature technique, and the discipline that strips a field clean without lifting a single package pad.

Recommended: