iMac Logic Board Repair Johannesburg | iAssist
iMac Logic Board RepairJohannesburg & Gauteng
No chime, no glow, no Apple logo — just a very expensive slab of aluminium playing dead. iStore writes these off. We hunt the failed component — a single shorted capacitor, a dead PMIC, a bad GPU IC — and replace only that. Free diagnostic, nationwide courier.
Free diagnostic · R1,500 – R5,500 · Microsoldering on-site · 6-month warranty
iMac logic board faults we repair
Dead iMac — no power
iMac completely unresponsive. Usually a blown power supply, failed power rail capacitor, or load-shedding surge damage to the logic board.
AMD Radeon GPU failure (27-inch)
Screen artefacts, distorted image, or display failure under GPU load. Logic board replacement — machine returns to full normal operation.
Black screen with iMac still running
Fan spins, drive spins, startup sound plays — but screen is dark. Backlight driver IC or display controller fault.
Random shutdowns during use
iMac cuts out unpredictably under load. Power management IC fault, capacitor failure, or thermal sensor issue.
USB-C / Thunderbolt ports not working
Ports not detecting devices, no display output, or no charging signal. Thunderbolt controller IC fault — repairable at component level.
Kernel panics and boot failures
Frequent kernel panics, inability to boot, or boot loop. Can indicate NAND fault, SMC failure, or corrupted boot controller.
Fan at maximum speed
Persistent full-speed fan from first boot. Failed temperature sensor IC or SMC fault — diagnosable and repairable.
Liquid damage to logic board
Board-level ultrasonic clean, corrosion removal, and IC replacement after liquid exposure.
iMac logic board repair price guide
Estimates only. Final price confirmed after free diagnostic. Written quote before any work begins.
| Service | Estimate |
|---|---|
| Logic board repair — component-level (Intel iMac) Power rail, capacitor, USB-C/TB controller, SMC fault. Board stays in machine. Data safe. |
R1,500 – R5,500 |
| Logic board repair — Apple Silicon (M1/M3/M4) M-series chip-level diagnosis and repair. More complex — assessment required. |
R2,500 – R5,500 |
| AMD Radeon GPU fault — logic board replacement (27-inch) Board replacement on affected 27-inch models. Machine returns to full normal operation. |
Assessment + quote |
| Power supply repair No-power diagnosis and repair — power supply unit or power circuit on logic board. |
R1,200 – R3,200 |
| USB-C / Thunderbolt controller repair IC-level repair for non-functioning ports. Board stays in the machine. |
R1,500 – R3,000 |
| Liquid damage treatment + board repair Ultrasonic clean, corrosion removal, component replacement after liquid exposure. |
R1,800 – R5,500 |
| Collection and return — Gauteng Door-to-door via Eliz Courier. Insured. |
R500 |
Power rail failures & board-level faults we repair
The following are the most common chip-level faults we diagnose and repair on iMac logic boards. This level of specificity is why we can fix machines that Apple and most repair centres write off as unrepairable.
Common power rail & IC failures we service under the microscope
- PPBUS_G3H short: The main power bus shorted to ground — common after load-shedding surges. Identified via resistance measurement; faulty MOSFET or capacitor located and replaced.
- ISL6259 / ISL9221 charging IC: Controls power delivery from the PSU to the logic board. Failure causes no-power or intermittent power symptoms. Chip replaced at component level.
- MOSFET failure on power rail: MOSFETs on the 12V, 5V, and 3.3V rails fail after thermal stress or surge damage. Each rail tested individually; faulty FETs replaced.
- EFI / SPI ROM chip corruption: The boot firmware chip can corrupt after failed macOS updates or bad NVRAM writes. We reflash the ROM directly — machine boots again without board replacement.
- GPU die solder failure (AMD Radeon): Logic board replacement on affected 27-inch models. The machine returns to full normal operation post-replacement.
- SMC / T2 chip fault: System Management Controller faults cause fan-at-full, no-power, or display failures. Chip-level diagnosis performed before any replacement decision.
iMac diagnostic LED guide — what each LED means
- LED 1 lit (only): Power from the wall is reaching the logic board. PSU is delivering standby voltage. Board-level fault or no power-on signal.
- LEDs 1 & 2 lit: Logic board is receiving power and the CPU has started. No GPU communication yet — GPU or VRAM fault likely.
- LEDs 1, 2 & 3 lit: GPU is communicating with the display. If screen is dark, fault is in the display panel, backlight, or cable — not the board.
- All 4 LEDs lit: Full system communication confirmed. If iMac still doesn't boot, fault is software or SSD — not hardware.
- No LEDs: No standby power reaching the board. PSU failure or blown fuse on the logic board power input.
Which iMac do you have?
Jump to your exact model for model-specific pricing, parts, and known faults.
iMac 24-inch M-series
View M-series repairs → 2017 XeoniMac Pro
View Pro repairs → 2019 - 2020iMac 27-inch (late Intel)
View 27" late Intel repairs → 2015 - 2017iMac 27-inch 5K
View 27" 5K repairs → 2013 - 2014iMac 27-inch
View 27" early repairs → 2017 - 2019iMac 21.5-inch 4K
View 21.5" 4K repairs → 2013 - 2015iMac 21.5-inch
View 21.5" early repairs →iMac logic board repair process
Free diagnostic
Board-level diagnosis using professional tools — we identify the exact failed component before quoting. No guesswork.
Written fixed-price quote
Full repair cost confirmed in writing. You decide whether to proceed. No charge if you decline.
Component-level repair
Under a stereo microscope with temperature-controlled soldering equipment, only the failed IC or circuit is replaced.
Post-repair stress test
Power cycling, display output, port function, thermal sensor readings, and fan response — all verified before return.
6-month warranty issued
Written warranty on the repaired component and labour. If the same fault reoccurs within 6 months, we fix it.
Collection or return
Pick up from our Silvamonte workshop or we arrange insured return delivery across Gauteng.
Three ways to get your iMac to us
Drop it off, arrange Gauteng collection, or ship from anywhere in South Africa. iMacs are heavy and the displays are fragile — we transport them properly.
Drop it off at the workshop
Walk in to our Silvamonte workshop any business day. Free parking, free diagnostic on the spot. Bring the original box if you still have it — otherwise we have appropriate transport packaging on hand.
11 Swemmer Rd, Silvamonte, Johannesburg
Mon-Fri 08:00-17:30 · Sat 08:00-14:00
Door-to-door via Eliz Courier
Eliz Courier & Messenger Services collects and returns your iMac across Joburg, Pretoria, Centurion, and the East Rand. R500 round-trip — slightly higher than our laptop rate because iMacs need specialist transport packaging and careful handling.
WhatsApp to book collection →Ship via The Courier Guy
Anywhere in South Africa — Cape Town, Durban, PE, Bloem, Polokwane. We arrange Courier Guy collection from your door with proper iMac packaging, repair, and return. Pricing depends on size; WhatsApp us with your model.
WhatsApp to arrange courier →iMac logic board repair — FAQ
Is it worth repairing an iMac logic board?
In most cases yes. Component-level microsoldering repairs only the specific failed chip or circuit — not the whole board. This costs a fraction of Apple out-of-warranty board replacement and your data stays completely safe throughout. We give you an honest written cost-benefit assessment before you commit.
My iMac 27-inch has GPU artefacts and the display distorts under load — what is the fault?
This is a classic AMD Radeon GPU failure common on 2015–2019 27-inch iMacs. The GPU die develops solder joint failures under thermal cycling. iAssist resolves this via logic board replacement — the machine returns to full normal operation after the board is swapped.
My iMac won't turn on at all — can you fix it?
Yes. A completely dead iMac is most often caused by a blown power supply, a failed power rail on the logic board, or a burnt capacitor — often from load-shedding power surges. Our technicians run a full board-level diagnostic to identify the exact fault before any work begins.
Can you repair iMac M1, M3, and M4 logic boards?
Yes — and this is where iAssist stands apart. Apple Silicon logic board repairs are declined by most South African repair centres due to their complexity. Our technicians are trained in component-level chip repair on M-series boards, diagnosing and fixing faults at chip level rather than swapping the entire board.
Will my data be safe during a logic board repair?
Yes. Component-level repair means only the failed chip is replaced — the storage drive is untouched throughout. Your data remains intact. If the fault has caused storage failure we will advise you separately on data recovery options.
My iMac fan runs at maximum speed constantly — is that a logic board fault?
Often yes. Persistent maximum fan speed is typically caused by a failed ambient temperature sensor IC, a disconnected sensor cable, or an SMC fault on the logic board. All are diagnosable and repairable at component level.
How long does iMac logic board repair take?
Board-level diagnostic is completed same day. Repair typically takes 1 to 5 business days depending on the complexity of the fault and parts availability. We give you a clear timeline upfront and keep you updated throughout.
Do you offer collection for iMac logic board repair?
Yes — R500 door-to-door collection and return across Gauteng. We handle transport of your iMac carefully. WhatsApp us on 078 742 4769 to arrange pickup from your door.
