Pad Repair Verification

Section Overview

This chapter has repaired every kind of pad — lifted, destroyed, through-hole, and fine-pitch — and each ended by pointing here, to the check that proves a pad repair sound (§6.1; §6.4). A pad is not a trace: it does two jobs at once, carrying a connection and holding a component, so verifying a pad repair means proving both — that it conducts and that it grips. That two-sided nature is the whole of this section. The electrical check is familiar: continuity and resistance from the component through the pad to its trace, near a known-good value, with no short to a neighbour — the verification discipline of Section 5.6 applied to a pad (§5.6). The mechanical check is what a pad adds: a repaired pad must physically hold its part, so you confirm its bond and its joint integrity — the combined electrical and mechanical soundness of the joint — by reading the solder fillet and by a pull test, a gentle, controlled tug on the component that a sound pad survives and a weak one gives up under. Beyond the bench, a pad repair is proven in service: the part must stay put and conduct under power, load, and time, as any repair must (§5.6). And it ends in a decision: a pad that passes both the electrical and the mechanical check is done; one that fails either is redone or, if it cannot be made sound, referred (§4.5). Learn to verify a pad both ways, to test it in service, and to judge and record it — and you close the pad-repair chapter able to prove your work.

Why This Matters

A pad has to do two jobs — conduct and hold — so a pad repair that is verified only one way is only half proven, and the unproven half is where it fails. This matters because a pad can conduct yet not hold: a joint that measures continuous can still be mechanically weak, so a re-adhered or rebuilt pad that passes the meter can still let its component fall off under stress, which only a mechanical check catches (§6.1). This matters because a pad can hold yet not conduct: a pad firmly bonded but poorly soldered, or disconnected from its trace, is mechanically fine and electrically dead, which only the meter catches (§6.2). It matters because pads carry real mechanical load: a connector, a large component, or a board that flexes puts force on its pads, so a pad repair that is not mechanically sound fails in service even when it tested electrically perfect. It matters because through-hole and fine-pitch pads add their own checks: a through-hole pad must be verified on both faces and through the hole, and a fine-pitch pad under magnification, so the verification scales with the pad (§6.3; §6.4). And it matters because an honest verdict is the point: a pad repair that fails either check is not finished, and knowing to redo or refer it — rather than return a pad that will drop its part or go open — is what makes a repair trustworthy (§4.5). Verify both jobs a pad does, and you return a pad that holds and conducts, not one that merely measures right.

Required Prerequisites

• Repair Verification — Section 5.6 set out the three-level verification discipline — electrical, mechanical, in service — that this section applies to a pad, with the added weight of the pad's mechanical job.
• Lifted Pad Repair — Section 6.1 and the pad repairs that follow it are what this section verifies; you verify a pad you have already repaired. This section includes powered testing — read the Safety Notes before starting.

Recommended Consumables

• A notebook, repair log, or label stock — to record what pad was repaired, how, and how it was verified
• Isopropyl alcohol and swabs — to clean flux from a repaired pad before inspecting it
• A solder mask pen — to reseal any point re-exposed while re-checking a pad (§5.3)
• Boards carrying real pad repairs — to practise judging pass or fail; do NOT return any pad you have not fully verified

Recommended Practice Hardware

• A multimeter with continuity and a low-ohms range — to measure a pad against a known-good value (§5.6)
• A magnifier or loupe and a bright, angled light — to read the solder fillet and inspect the bond and the pad
• Fine tweezers or a fine probe — to apply a gentle, controlled pull test to a component
• A safe, current-limited bench supply — to power a repaired board for functional and load testing (§5.6)
• A known-good reference — an identical working board or an undamaged pad — to measure a repair against
• Good ventilation and eye protection — to work safely when a repaired board is first powered

Real-World Applications

Pad verification is the step that decides whether a repaired part will stay put and work, and disciplined technicians run both its checks on every pad. A technician who has re-adhered a lifted pad tugs the component gently and measures continuity before trusting the repair, catching a pad that held but read open (§6.1). Someone returning a board with a rebuilt pad load tests it and gives the part a pull test so a weak bond fails on the bench, not in the customer's hands (§6.2). A repairer of a through-hole pad verifies continuity on both faces and through the hole before refitting the part (§6.3). A technician on a fine-pitch repair inspects every joint under magnification for a sound fillet and no bridge (§6.4). And a repairer whose pad fails a pull test treats it as unfinished, redoes the bond, and re-verifies rather than shipping a part that will fall off (§4.5). The failures this skill prevents: returning a pad that conducts but will not hold, one that holds but is electrically dead, and one that passes on the bench but fails under the part's own load.

Common Challenges

• Checking only the meter. A pad that reads continuous can still be mechanically weak — add a pull test and read the fillet, not just the resistance (§6.1).
• Checking only the hold. A firmly-bonded pad can still be electrically dead — measure continuity to the trace as well (§6.2).
• Skipping the second face. A through-hole pad sound on top can be open underneath — verify both faces and through the hole (§6.3).

Safety Notes

Risk Level: Medium. The measuring, inspecting, and pull-testing are low-risk, but pad verification ends by powering a freshly-repaired board, which carries the usual first-power-up hazards.

Professional Tips Before Starting

• Verify both jobs, always. Check that a pad both conducts and holds before you call it done — a pad that does only one is not repaired (§6.1).
• Pull gently and deliberately. A controlled tug confirms the bond; a hard one destroys it — test the hold, do not break it.
• Measure against a reference. Compare a pad's resistance to a known-good one, not to zero — the comparison is what reveals a marginal joint (§5.6).

Verifying a Pad Repair

Recap and Frame

This chapter repaired pads of every kind, and this closing section proves them, drawing the whole chapter to the same disciplined end every repair reaches (§6.1; §6.4). The frame to hold — the one idea that shapes pad verification — is that a pad does two jobs at once: it carries an electrical connection into the circuit, and it physically holds a component in place. A trace only had to conduct, so verifying a trace repair was about continuity, resistance, and shorts (§5.6). A pad has to conduct and hold, so verifying a pad repair adds a second, mechanical question the trace never posed: will it keep its grip? This is why a pad repair is verified on two axes. The electrical axis asks does it conduct correctly — continuity and resistance to the trace, near a known-good value, with no short (§5.6). The mechanical axis asks does it hold — a sound bond, a good solder fillet, and a component that survives a gentle pull. A pad must pass both, because each hides the other's failures: a pad can measure perfect and still let its part fall off, or grip firmly and still be electrically dead. On top of the two axes sit the same in-service checks as any repair, and the same honest pass-or-fail decision (§5.6; §4.5). So this section walks why both checks are needed, the mechanical check, the electrical check, in-service verification, and the decision and record. Hold the frame — a pad conducts and holds, so verify both — and no pad repair leaves your bench half-proven.

Why a Pad Needs Both Checks

The heart of pad verification is that its two jobs fail independently, so one check can pass while the other fails, and only doing both catches every fault. Consider a pad that conducts but does not hold. A lifted pad re-adhered with weak or under-cured glue, or a rebuilt pad bonded to marginal laminate, can make a perfectly good electrical joint while its bond to the board is poor (§6.1). The meter reads continuous, the repair looks done — and then the component, under the stress of handling, heat, or its own weight, peels the pad off, because nothing verified the hold. Now consider a pad that holds but does not conduct. A pad firmly bonded and soldered can still be disconnected from its trace — its thin link torn and never rebuilt — or joined by a cold joint that grips mechanically but conducts poorly (§6.2; cold joint). A pull test passes, the pad is solid — and the circuit is dead, because nothing verified the connection. These are not edge cases: they are the two commonest ways a pad repair that "looked fine" fails, and each is invisible to the other's test. This is the whole argument for two checks: a pad's joint integrity — its soundness as both a mechanical anchor and an electrical connection — is only proven when both are tested, because a joint sound in one respect can be unsound in the other. Test only one, and you ship the other's failure. Verify both, and neither kind of failure gets past you.

The Mechanical Check

The mechanical check proves the pad holds, and it has two parts: reading the joint by eye, and testing it by a gentle pull. Read the joint first. Under magnification, inspect the solder fillet — the concave sweep of solder between the component and the pad — because a good fillet, smooth and well-wetted, is the visible sign of a sound mechanical and electrical joint, while a cracked, disturbed, or ball-shaped one is a warning; note that lead-free solder solidifies naturally duller than tin-lead even when sound, so cracking and poor wetting are more reliable warning signs than dullness alone (solder fillet; wetting). Check the pad's bond too: the pad itself should sit flat and fully stuck to the board, with no lifting at its edges, especially on a re-adhered or rebuilt pad whose bond is fresh (§6.1). Then apply a pull test. With fine tweezers or a fingertip, give the component a gentle, controlled tug or a light sideways nudge — enough to load the joint, not to wrench it — and watch the pad: a sound pad and joint hold firm and unmoved, while a weak one shifts, lifts, or lets the part come away. Keep it gentle and deliberate: the pull test verifies the repair, it does not stress it to destruction, and a hard yank will tear a good pad off and turn a test into damage. Match the force to the pad: a large through-hole part can take a firmer tug than a delicate fine-pitch lead, which needs only the lightest touch under magnification (§6.4). A pad with a sound fillet, a flat bond, and a component that holds under a gentle pull has passed the mechanical check — it will keep its grip in service. Read the joint and test the hold, and you have proven the half of a pad repair the meter cannot see.

The Electrical Check

The electrical check proves the pad conducts, and it is the trace-verification discipline of Section 5.6 applied through the pad to its component and its trace (§5.6). Start with continuity: with the board unpowered, confirm the beeper sounds along the path from the component, through the pad, to the trace it should feed, proving the connection is closed. Then measure resistance: on a low-ohms range, read the joint and compare it to a known-good pad and trace, because a repaired pad should conduct as well as a healthy one, and a reading well above the reference flags a cold or incomplete joint that grips but does not truly conduct (§5.6; cold joint). Check for shorts: confirm the repaired pad connects only to what it should and not to a neighbour, which matters most on the close-packed pads of a fine-pitch part where a whisker bridges two signals (§6.4). For a through-hole pad, verify both faces and the hole: measure continuity ring-to-ring through the hole and each ring to its trace, because a through-hole pad can be sound on one face and open on the other or through the barrel (§6.3). Trace the connection fully: a pad joins a component to a trace, so confirm the whole path — component to pad, pad to trace — is continuous and low in resistance, not just that the solder looks shiny. A pad continuous to its trace, near a known-good resistance, with no short and both faces sound, has passed the electrical check — it truly conducts. Measure the whole path against a reference, and you have proven the half of a pad repair the eye cannot see.

Functional and In-Service Verification

As with any repair, the real proof of a pad is in service — the part must stay put and conduct under power, load, and time, not just on the unpowered bench (§5.6). Test the function first: power the board carefully and defensively, and confirm the part on the repaired pad actually works — the circuit it serves does what it should (§5.6). Then load it: put the real operating current through the repaired pad, because a marginal joint can pass a continuity beep and a light function check yet drop voltage or heat when the true load is drawn (load test). Watch for heat at the pad: a repaired pad that warms under its normal current carries too much resistance and needs redoing. Weigh the mechanical stress of service: a pad holds its part against handling, vibration, heat cycling, and the part's own weight, so consider whether the repair will take the mechanical life the pad must live — a heavy connector on a re-adhered pad is a harder ask than a tiny resistor. For a repair that must last, soak it: run the board under power over time so a bond or joint that is only just holding fails on your bench rather than in the field (soak test). A pad that works, carries its load without heating, holds its part through the stresses of use, and survives a soak has passed the level that matters most. Prove it in service, and you have tested the pad against the real conditions it must survive.

The Pass-or-Fail Decision and Recording

Pad verification ends where every verification ends — in an honest judgement and a record — with the pad's two jobs both weighed (§5.6). The rule is that a pad must pass both checks: mechanically sound and electrically sound, and holding under service, or it is not finished (§4.5). When a pad fails, diagnose which job failed: a failed pull test or a lifted edge points to a weak bond — re-adhere or rebuild it more soundly; a high resistance or an open points to a cold joint or a broken trace link — reflow or reconnect it (§6.1; §6.2). Then redo and re-verify: fix the failed half and test both again from the top, because a re-verified pad is the only kind you can trust. Know when to stop: if a pad cannot be made to hold and conduct — the laminate is gone, the site is destroyed, the fine-pitch damage is beyond a hand repair — then the honest verdict is beyond hand repair, and the board is referred or replaced rather than returned with a pad that will fail (§6.4; §4.5). This weighs heaviest on a safety-critical or load-bearing pad: a pad that must hold a part carrying real current or force, and that you cannot verify to that standard, must never go back into service. Then record the repair: note which pad was repaired, by which method, and that it passed both the mechanical and the electrical check, so the repair is documented for whoever follows (§5.6). A pad that passes both checks and in service, judged honestly and recorded, is a finished, trustworthy repair — and with it the pad-repair chapter is complete. Judge both jobs and record the result, and every pad you return is one you can stand behind.

Common Mistakes

• Verifying electrically only. A pad that reads continuous can still be mechanically weak — add a gentle pull test and read the fillet (§6.1).
• Verifying mechanically only. A solid pad can still be electrically dead — measure continuity through the pad to its trace (§6.2).
• Pulling too hard. A hard yank tears off a good pad — keep the pull test gentle and controlled.
• Skipping the second face. A through-hole pad can be sound on top and open beneath — verify both faces and through the hole (§6.3).
• Passing a failed pad. A pad that fails either check is not finished — redo and re-verify it, or refer it (§4.5).

Troubleshooting Guidance

Pad-verification problems come down to a pad that fails the mechanical check, the electrical check, or in service. If the component moves under a gentle pull: the bond is weak — re-adhere or rebuild the pad more soundly and re-cure fully (§6.1). If the pad reads open or high-resistance: it is a cold joint or a broken trace link — reflow it or rebuild the connection (§6.2; cold joint). If it is sound on one face but open through a hole: the barrel or a ring is the fault — restore the through-connection (§6.3). If a fine-pitch pad shows a bridge: inspect under magnification and wick it clear (§6.4). If the pad warms under load: it carries too much resistance — redo the joint (load test). If a heavy part on a re-adhered pad works loose in service: the bond could not take the mechanical load — rebuild it more robustly or reinforce it. If a pad cannot be made to hold and conduct: it is beyond hand repair — refer or replace (§4.5). If you are unsure a pad is done: test both jobs, not one. The throughline: verify hold and conduction both, in service, then judge and record.

Verification & Testing Methods

Run both checks, then the in-service check, before trusting any pad repair:

• [ ] I read the solder fillet and the pad's bond under magnification and confirmed the pad sits flat and fully stuck (solder fillet).
• [ ] I applied a gentle pull test and the component held firm without shifting or lifting.
• [ ] I verified continuity and resistance from the component through the pad to its trace, near a known-good value, with no short (§5.6).
• [ ] I verified a through-hole pad on both faces and through the hole, and a fine-pitch pad under magnification (§6.3; §6.4).
• [ ] I confirmed the pad's joint integrity in service under function and load, then made an honest pass-or-fail decision and recorded the repair (§4.5).

Then try the practice exercises below — hands-on verification practice on repaired scrap boards; scenarios differ from the quiz.

Practice Exercises

1. Read and pull (6 minutes, hands-on). For a repaired pad, inspect its solder fillet and bond under magnification, then give the component a gentle, controlled pull test and judge whether it holds (solder fillet).
2. Measure the path (6 minutes, hands-on). Measure continuity and resistance from the component through the pad to its trace, comparing to a known-good pad, and check for a short to a neighbour (§5.6).
3. Both faces (5 minutes, hands-on). On a through-hole pad repair, verify the connection on both faces and through the hole (§6.3).
4. Judge and record (5 minutes, reasoning). Decide from your two checks whether the pad passes, fails, or must be referred, and write down the repair and how you verified it (§4.5).

These core ideas — why a pad needs both checks, the mechanical check and pull test, the electrical check, in-service verification, and the pass-or-fail decision and record — are tested in the Chapter Quiz at the end of this chapter, where a score of 80% is required to continue.

Key Takeaways

• A pad does two jobs — it conducts and it holds — so a pad repair must be verified both electrically and mechanically, because each check hides the other's failures (§6.1).
• The mechanical check reads the solder fillet and the pad's bond and applies a gentle pull test: a sound pad holds firm, a weak one shifts or lets the part come away (solder fillet).
• The electrical check measures continuity and resistance from the component through the pad to its trace, near a known-good value, with no short — and both faces on a through-hole pad (§5.6; §6.3).
• A pad's joint integrity — its soundness as both anchor and connection — is only proven when both checks pass, plus the in-service checks of function, load, and soak (§5.6).
• A pad that fails either check is not finished: redo and re-verify it, or if it cannot be made to hold and conduct, refer or replace — then record the repair (§4.5).

Skills Learned

• You can now explain why a pad repair needs both a mechanical and an electrical check.
• You can now test a repaired pad's mechanical hold with a pull test.
• You can now verify a pad's electrical connection to its component and trace.
• You can now verify a pad repair in service under function and load.
• You can now make the pass or fail decision and record a pad repair.

Glossary Additions

• joint integrity — the overall soundness of a soldered joint or repaired pad as both a mechanical anchor and an electrical connection, so that it both holds its component firmly and conducts fully to the circuit. Because a joint can be sound in one respect and unsound in the other — mechanically solid but electrically open, or electrically continuous but weakly bonded — joint integrity is only confirmed by verifying both, which is why a pad repair is checked mechanically (fillet, bond, pull test) and electrically (continuity, resistance, no short). A joint with good integrity survives both the meter and a gentle pull, and holds and conducts in service.
• pull test — a mechanical check of a pad or joint in which a gentle, controlled tug or nudge is applied to a component to confirm that the pad is soundly bonded and the joint holds, without applying enough force to damage a good repair. A sound pad and joint stay firm and unmoved under a pull test, while a weak bond shifts, lifts, or lets the component come away, revealing a mechanical failure the meter cannot detect. The force is matched to the pad — firmer for a robust through-hole part, very light for a delicate fine-pitch lead under magnification — and the test verifies the repair rather than stressing it to destruction.

Suggested Next Sections

Must read next:

• Identifying Via Failures — Chapter 7 turns from pads to vias, the plated holes and connections that carry a signal between layers; its first section teaches how to find and identify a failed via, the diagnosis every via repair begins from.

Recommended:

• Repair Verification — the three-level verification discipline this section applies to a pad.
• Lifted Pad Repair — the first pad repair, and the assessment and re-adhesion whose hold this section proves.