Open up almost any modern industrial control board — a CompactLogix processor, a Siemens HMI, a PowerFlex 755 control card, a servo drive position controller — and you will find at least one BGA package. Often more than one. The CPU, FPGA, graphics controller, communication ASIC, and high-pin-count memory devices all live underneath BGA packages today. When one of those chips fails, the board is electrically dead. Without proper rework capability, the only option the OEM gives you is replacement at full price.
BGA replacement is not a DIY operation. It needs a calibrated rework station, proper stencils, X-ray inspection, and an operator with hundreds of hours of practice. But for plants that depend on legacy or hard-to-source boards, it is one of the highest-value services a repair shop offers. At Flexa Systems, BGA replacement is part of the component-level repair process for PLCs, HMIs, VFDs, and servo drives across all major brands. Every BGA reflow we perform is verified under X-ray, tested under load, and returned with a 2-year warranty.
What a BGA Is and Where It Appears in Industrial Controls
BGA stands for Ball Grid Array. Instead of legs around the perimeter of the package (like a QFP or SOIC), a BGA chip has a grid of solder balls underneath the package body. The balls form both the electrical and mechanical connections to the board. This packaging style is essential for high pin counts — modern processors have several hundred I/O pins that simply will not fit around a perimeter package.
Common BGA applications in industrial controls:
- PLC processors — Allen-Bradley CompactLogix, ControlLogix, MicroLogix; Siemens S7-1200, S7-1500, S7-300 CPUs; Mitsubishi Q-series, FX-series; Omron CJ-series and NJ-series
- HMI main processor and graphics — PanelView Plus 6/7, Siemens TP/KP/Comfort panels, Pro-face GP series, Mitsubishi GOT2000/GOT1000 — all use BGA-packaged ARM SoCs and graphics controllers
- VFD control boards — DSP and microcontroller chips (often TI, Freescale, NXP) that handle PWM generation, motor control loops, and communication. PowerFlex 753/755, ABB ACS880, Yaskawa A1000/GA800, Siemens G120/SINAMICS
- Servo drive position controllers — Kinetix series, Sigma series, MR-J4 series — high-performance position loop processing requires BGA-packaged DSPs
- Communication processors — EtherNet/IP, PROFINET, EtherCAT, DeviceNet ASICs in option cards
- FPGA and CPLD devices — for custom logic, encoder interpolation, fast I/O processing
Once a board uses BGA packaging, conventional through-hole repair techniques are useless. Without rework capability, that board is effectively unrepairable.
Why BGA Chips Fail in Industrial Environments
Industrial environments stress BGA solder joints in ways that consumer electronics rarely see. Understanding the failure modes helps both prevent them and decide when replacement is worthwhile.
Thermal Cycling
Industrial control boards experience constant temperature changes. A drive on a stamping line might cycle from 25°C ambient to 85°C internal multiple times a day as the load varies. A PLC in an outdoor cabinet sees daily and seasonal swings of 40°C or more. Each thermal cycle expands and contracts the solder balls slightly, and the mismatch in coefficient of thermal expansion between the chip, the solder, and the PCB creates shear stress at the joints.
Over thousands of cycles — typical of a board in 5-10 year service — micro-cracks develop at the corner balls of the BGA. The corners are stressed most because they are furthest from the package centerline. A typical failure mode: the chip works fine when cold or stable, but faults intermittently as the board warms up and then settles. By the time the failure becomes consistent, the cracked balls have completely separated.
Vibration and Mechanical Shock
Vibration from nearby motors, presses, or compressors propagates through panel mounting and into the PCB. BGAs are particularly vulnerable because the solder balls cannot flex — there is no compliant lead like a QFP gull-wing pin. Sustained vibration at certain frequencies will work-harden the solder until cracks form.
This is most common on drive boards mounted near the motor itself, or on machine-tool servo controllers exposed to spindle vibration. The symptom is typically random faults that correlate with machine activity.
Voids and Process Defects
Some BGA failures originate at the factory. Voids form in solder balls during reflow if the flux activator volatilizes too aggressively or if the profile is wrong for the package. A void itself does not cause immediate failure, but it concentrates stress and accelerates fatigue. Boards with high-void-percentage joints fail much earlier than properly soldered ones.
This is why post-rework X-ray inspection matters. A BGA that looks fine externally can have invisible voids inside the joints, and only X-ray reveals them.
Lead-Free Solder Joint Embrittlement
RoHS-compliant lead-free solder is mechanically less compliant than the leaded solder of older boards. Tin-silver-copper alloys harden over time and become more brittle. Boards manufactured between 2006 and 2012 — the early lead-free era — show higher rates of BGA cracking after 8-10 years in service than either older leaded boards or newer ones with refined alloys.
Moisture and Pop-corning
If a BGA package absorbs moisture during storage and is then reflowed without proper bake-out, the moisture vaporizes inside the package and creates internal cracks — known as pop-corning. The chip may still work but is fragile, and any future thermal stress can complete the failure. This is purely a manufacturing-quality issue, but boards from certain production lots are more vulnerable than others.
Diagnosing a BGA Failure
BGA failures are tricky to diagnose because the chip itself is often still functional internally — only the connections are bad. Standard component testing (resistance, in-circuit functional check) often appears normal because intact balls bridge the broken ones during measurement. Real diagnosis requires:
- Functional testing under thermal stress — heat the suspect area with a focused hot-air source and look for the symptom appearing or disappearing as the board warms or cools
- Boundary scan / JTAG — for chips that support it, the test access port can detect open balls by reading back I/O states that should be driven
- X-ray inspection — direct visual confirmation. Cracked or voided joints show up clearly in 2D X-ray; for ambiguous cases, oblique-angle or CT scanning is decisive
- Electrical signature comparison — comparing impedance signatures of the suspect board against a known-good reference reveals open and shorted joints
- Process-of-elimination — once power, clocks, and reset are confirmed correct, an unresponsive BGA is the most likely candidate
Some BGA failures can be temporarily revived by reflowing the existing package — the so-called "reflow rescue." This is sometimes useful as a diagnostic step (if the symptom clears after reflow, the joints were the problem) but it is not a permanent fix. Cracked balls re-form their cracks within weeks or months. Replacement of the chip with new balls is the correct repair.
The BGA Replacement Process
Pre-Rework Preparation
Before any heat hits the board, preparation matters more than people expect:
- Bake the board — moisture in the substrate vaporizes during reflow and damages traces. A 24-hour bake at 85-100°C drives moisture out before rework
- Document the chip orientation — pin 1 marker, alignment relative to silkscreen. A misoriented BGA is the most expensive mistake in this process
- Capture functional baseline — voltages on rails, key signals, error codes. Confirms that other parts of the board are not contributing to the symptom
- Shield surrounding components — Kapton tape and heat shields prevent neighboring components from being damaged by hot air spillage
Removal
The failed BGA is heated with a focused IR or hot-air rework station while the board is supported on a heated bottom platen. The bottom platen brings the entire board up to ~150°C so that the rework station only has to deliver the additional energy to reflow the solder under the chip. Without bottom heat, the entire reflow energy must come from above, and the surrounding board area gets damaged.
Once solder reflow temperature (220-250°C for lead-free, 183-210°C for leaded) is reached, the chip lifts off cleanly with a vacuum tool. The remaining solder on the pads is wicked away with desoldering braid, and the pads are cleaned with isopropyl and inspected under magnification. Damaged pads — lifted, cracked, or with insufficient solder mask — must be repaired before the new chip goes down.
Reballing or New Chip
Two options exist depending on the failure type and chip availability:
- Reball the original chip — when the failure was solder-joint fatigue but the silicon is intact. The old balls are removed, the chip is cleaned, and a stencil with fresh balls (typically 0.4 mm to 0.8 mm depending on package) is aligned and reflowed onto the chip's BGA pad array. Reballed chips perform identically to new-balled ones
- Source a new chip — when the silicon is damaged or when the chip is unavailable in legitimate channels (counterfeit BGA chips are an industry-wide problem in obsolete part markets). New chips come pre-balled from the manufacturer and go directly to placement
Placement and Reflow
The replacement chip is aligned to the board pads using vision systems on the rework station — typical alignment accuracy is ±25 microns, well within the tolerance for 0.5 mm pitch BGAs. The full reflow profile is then run: ramp up, soak, peak, cool. The profile must match the package and solder type — wrong profile causes cold joints, voids, or thermal damage to the chip.
X-ray Inspection
This is the step that distinguishes professional rework from DIY attempts. Every BGA we replace is inspected under 2D X-ray to verify:
- All balls present and roughly equal in diameter
- No voids exceeding 25% of joint area (industry IPC-7095 limit)
- No bridges between adjacent balls
- No solder spheres or contamination between joints
- Acceptable standoff height — the gap between chip and board should be uniform across all balls
Without X-ray, you cannot confirm that the rework actually succeeded. A board that powers up and runs initial diagnostics may still have a single bad joint that fails under load or after a few thermal cycles. X-ray inspection catches these defects before the board ships.
Functional and Burn-In Testing
The final step is putting the repaired board through full functional testing — power-up, communication, all I/O, full load if applicable — followed by burn-in at elevated temperature for 24-48 hours. Burn-in stresses any marginal joints and exposes them while the board is still in the shop, not after it ships.
Common Industrial BGA Replacement Scenarios
CompactLogix and ControlLogix Processor Failures
The L1, L3, and L7 processor modules use BGA-packaged ARM and PowerPC chips. Symptoms: no boot, intermittent communication faults, random major faults during cold weather. Replacement of the main processor BGA typically restores the module fully — no firmware loss, all calibration retained.
PanelView and Siemens HMI Graphics Chip Failures
HMI symptoms — black screen, flickering, partial display, garbled colors — often trace to the graphics controller BGA. The main system processor is fine; the graphics chip alone is bad. BGA replacement on these chips is a common repair on aged HMIs.
VFD Control Card DSP Failures
Drives with random fault codes, unstable speed regulation, or communication dropouts often have a degraded DSP. Replacement of the DSP BGA restores motor control loop stability. Common on PowerFlex 70/700 series and ABB ACS800/850 control cards in their second decade of service.
Servo Drive Position Controller Failures
Position errors, encoder fault codes, and jitter on long moves can all originate from a failing position-controller DSP. Kinetix and MR-J4 series use BGA chips for this function, and replacement is a viable repair when the rest of the drive is healthy.
When BGA Replacement Makes Economic Sense
Not every board with a failed BGA is worth replacing the chip. The decision depends on three factors:
- Replacement cost vs repair cost — a new processor module from the OEM is typically 5-10x the cost of component-level BGA replacement. A new HMI is 3-5x. A new VFD control card from the OEM, where available, can be 8-15x. Repair is almost always the right financial choice when the board is otherwise healthy
- OEM lead time — replacement parts for legacy CompactLogix L1, S7-300, PowerFlex 700, and similar are now 8-16 weeks from the OEM, sometimes longer. Component-level repair is 5-10 days. Downtime cost dominates the equation
- Board condition outside the BGA — if the rest of the board is corroded, has multiple component failures, or shows signs of mechanical damage, the BGA replacement still leaves a fragile board. Better to scrap and replace. If the rest of the board is clean, repair extends life by 5-10 years
For high-value boards on legacy systems — where the OEM no longer supports the part — BGA replacement is often the only path forward. Plants that successfully extend the life of their installed base typically have a relationship with a repair shop that has BGA capability.
What to Send and How to Send It
If you have a board you suspect has a BGA failure, send it for evaluation. We provide free diagnostics — no charge if we determine the board is unrepairable or if BGA replacement is not the actual fix. Pack the board in anti-static bag with proper foam, include a description of the failure as observed in the field, and we will respond within 24-48 hours with a diagnosis and quote.
If the failure is BGA-related, replacement turnaround is typically 5-10 business days. The repaired board returns with X-ray inspection records, full functional test results, and a 2-year warranty.
Conclusion
BGA chips are everywhere on modern industrial control boards, and they fail with predictable patterns. Thermal cycling and vibration are the dominant causes, accelerated by lead-free solder embrittlement and occasional manufacturing voids. Diagnosis requires functional testing and X-ray inspection; repair requires a calibrated rework station, proper stencils, and operator skill.
For plants that depend on legacy or hard-to-source boards, BGA replacement is the difference between a repaired board back in service in a week and a multi-week wait for an expensive new module. Done correctly, with full X-ray verification and burn-in, the repaired board performs identically to a new one and delivers another decade of service.
If you have a PLC, HMI, VFD, or servo drive board that you suspect has a BGA failure, contact Flexa Systems. We provide free diagnostics, fast component-level BGA replacement, X-ray inspection, full burn-in testing, and a 2-year warranty on every board we return to service.