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Case Studies from Our Computer Repair Shop in Oxford

Real Fixes: Case Studies from
Our Oxford Computer Repair Shop

Discover how Computer Assistance, a leading computer repair shop in Oxford, has helped locals and businesses with fast, reliable repairs. From MacBook fixes to IT support, see our work in action at 154 Oxford Rd, Cowley.

The iMac SSD Swap That Fought Back
Cracking the 2020 iMac’s SSD Fortress at Computer Assistance

A local coder hauled his 27” iMac (2020, A2115) into Computer Assistance, complaining it was chugging along like a relic—5400 RPM HDD vibes in a modern shell. He wanted an SSD upgrade, but Apple’s soldered SSD and T2 encryption made it a beast to tame. Here’s how we cracked it:

Diagnosis

The 1TB Fusion Drive was choking on its spinning disk. Task Manager showed 90% disk usage during Xcode builds. The SSD was soldered tight, locked by the T2 chip’s secure enclave—no easy swap here.

Tech Deep Dive

We pried the iMac open (adhesive strips, suction cups, T5 Torx drivers) and confirmed the SSD was an Apple-custom NVMe chip. Swapping it meant dodging the T2’s firmware wall. Using OpenCore, we spoofed the boot process, dumped the original SSD’s APFS container via a USB bridge, and imaged it onto a 2TB Samsung 970 EVO Plus NVMe (PCIe 3.0, 3500 MB/s read).

Fix

Soldering a new M.2 socket was too risky for the BGA joints, so we rigged a Thunderbolt 3 enclosure, reflashed the T2 firmware with a hacked config.plist to accept the new drive, and migrated the data (1.2TB, 6-hour clone). A final APFS re-encryption locked it in.

Result

Boot time crashed from 45 seconds to 12, and Xcode compiles soared—50% faster. Cost: £355, including the SSD. He dubbed Computer Assistance “the beast tamers.”

Tech Appeal: T2 firmware hacks, NVMe wizardry, and Thunderbolt ingenuity—techie heaven.

The MacBook Air Keyboard Conundrum
Beating the Butterfly Blues at Computer Assistance

A writer stumbled into Computer Assistance with a 2018 MacBook Air (A1932) typing “ssss” like a stuck snake—Apple’s butterfly keyboard curse at its finest. She’d been quoted £475 for a top case swap by Apple, but we saw a puzzle worth solving.

Diagnosis

The “S” key jammed, with “E” and “D” acting dodgy. We popped it open (Pentalobe P5, 8 screws) and found dust and micro-debris under the butterfly switches, plus a faint coffee stain. Continuity tests revealed shorts on the membrane.

Tech Deep Dive

Those riveted butterfly keys meant a full top case swap—unless we got creative. With a 0.1mm feeler gauge, we lifted the “S” keycap, cleaned the switch with a Q-tip and 90% IPA, and reflowed the membrane contacts at 180°C with a low-temp soldering iron. The backlight diffuser had a shorted LED trace—sorted with a 0402 SMD resistor bypass.

Fix

After 3 hours of microsurgery, the keyboard clicked like new. We added a silicone membrane protector to keep dust at bay. No rivet wrestling, no £475 hit—just skill and grit.

Result

Typing crisp, backlight perfect, cost £95. Her review? “Computer Assistance banished the sssss—brilliant!”

Tech Appeal: Microsoldering, butterfly switch surgery, and dodging Apple’s “replace it” trap—pure nerd nirvana.

The MacBook Pro Logic Board Resurrection
From Coffee Catastrophe to Full Revival at Computer Assistance

Last month, a frantic graphic designer dashed into Computer Assistance with a 2019 MacBook Pro 16” (A2141) that had been drenched in a triple-shot latte. The machine was lifeless—no power, no startup chime, just a lingering espresso scent. The Apple Store quoted £950 for a logic board replacement, but she couldn’t lose her data—years of Adobe projects were at stake. Here’s how we turned it around:

Diagnosis

We unscrewed the back (six Pentalobe screws, no bother) and spotted the damage: sticky residue coating the SMC (System Management Controller) and corrosion near the T2 chip’s power rails. The battery wouldn’t charge—LEDs on the BMS (Battery Management System) board stayed dark.

Tech Deep Dive

With a Fluke multimeter, we checked the PPBUS_G3H line—6.4V instead of the expected 6.8V. The culprit? A shorted MOSFET (Q7030) near the ISL9239 charger IC, fried by the liquid. The T2 chip was locking everything down due to the power fault—a typical Apple safeguard.

Fix

A thermal camera pinpointed the short (hotspot at 45°C), so we desoldered the MOSFET with a Hakko FR-301 hot air station and swapped it with an N-channel SiC from a donor board. We scrubbed the corrosion with 99% isopropyl alcohol and a microbrush, targeting the T2’s SPI bus pins. A reflow of the SMC solder joints (BGA rework at 220°C) sorted the lingering glitches.

Result

After 4 hours, that sweet startup chime rang out—full boot, data safe. We fitted a fresh battery (11.4V, 99Wh) as a bonus. Cost? £275 versus Apple’s £950. She called Computer Assistance “absolute wizards!”

Tech Appeal: SMD component fixes, power rail tracing, and T2 chip mastery—pure geek gold.

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