Diagnostics · motherboard
Motherboard diagnostics, structured instead of improvised.
"Dead board", "won't charge", "shuts down under load": behind every symptom there's a fault tree. WrenchBoard walks it with you (known failure rules, the schematic's electrical graph, an ordered measurement protocol) down to the component to replace.
Open your board in the browser01The cost
Why random probing is so expensive
A modern motherboard is thousands of components and dozens of interdependent power rails. Probing at random means hours lost, and sometimes a second fault created along the way. Senior techs don’t probe at random: they walk a mental fault tree. No LED? Input voltage first. Present? The fuse. Intact? The first regulator in the chain. Every measurement eliminates an entire branch.
The problem: that tree lives in senior techs’ heads and in scattered forum threads. WrenchBoard makes it executable.
02The method
The method: symptom, rules, graph, protocol
A WrenchBoard diagnostic session moves in four beats:
- The symptom, in plain language. “Board dead, no LED, 24 V adapter plugged in.” No forms, no codes: you describe what you see at the bench.
- The device’s failure rules. The per-device knowledge base maps symptoms to known causes, each with a confidence score. An input fuse blocking the main rail comes out on top with its probability.
- The electrical graph. If the schematic has been ingested, the agent checks its hypotheses against the real topology: which components drop if this rail drops, what must come up before what in the boot sequence. It can simulate a failure cascade before you touch the board.
- The measurement protocol. The hypothesis lands as ordered, typed steps: continuity across
F1, voltage atR49, diode-mode reading on the suspect rail. The boardview zooms onto each probe point the moment the agent sends you there.
With every reported result the hypothesis tightens or pivots. The repair journal keeps everything: readings, before/after diffs, confirmed cause.
03No embellishment
An agent that doesn’t make things up
The value of an AI agent in a diagnostic loop depends entirely on its reliability. An assistant that invents a test point costs more time than it saves. WrenchBoard applies strict discipline, detailed on the AI for electronics repair page:
- every cited refdes is validated against the parsed board: a non-existent component is flagged, never asserted;
- proposed causes come from the device’s audited rules or the compiled electrical graph, not from the model’s memory;
- when the agent steps outside established rules to reason on topology alone, it says so.
04Shop memory
From one-off diagnosis to shop memory
A diagnosed fault is only useful if it serves the next one. At the end of a session the confirmed cause is recorded; recurring patterns and diagnostic playbooks are shared across devices. The tenth board of the same model with the same symptom is diagnosed in minutes: the agent starts from what already worked.
It’s the same logic that makes WrenchBoard a complete microsoldering software rather than a lookup tool: knowledge accumulates where the work happens.
05Start
Start on a covered board
The free plan gives access to devices covered by the knowledge base, in the browser, no install. Describe a real symptom and watch the agent walk its fault tree. The two-minute demo on the home page shows a full session on a real board.
Watch it work
The same agent, on a real board
This is not a mockup, it is the bench itself with its own interface, running on the MNT Reform pack exported from the engine: 487 real components and 2066 real pads. Every step below is what the engine answers on this board, from the device's rules for the symptom to the schematic graph behind the input fuse F1 and the board net it feeds. Here is what the agent does with a board that will not power up.
Eight tool calls, each one a real answer from the engine on this board, and not one component named from memory.
FAQ
Frequently asked questions
Which motherboard faults does the software help diagnose?
Everything that can be reasoned about at component level: dead board (no LED, no voltage), missing or collapsed power rails, shorts, charging faults, components running hot. The agent starts from the symptom, cross-checks it against the device's failure rules and proposes a ranked hypothesis with its verification protocol.
Do I need the board's schematic to diagnose?
It's better, but not mandatory. On devices covered by the knowledge base, failure rules plus the boardview are enough to run a protocol. With the schematic ingested, the agent additionally reasons over the full electrical graph: cascade simulation, upstream/downstream rails, boot sequence.
Does the tool tell me the failing component directly?
It gives you the most probable suspect and the way to confirm it. Diagnosis stays a loop: hypothesis, bench measurement, result, tightened hypothesis. WrenchBoard orders that loop; you hold the probes.
What happens if my symptom isn't covered by the rules?
The agent doesn't stop: it explores the schematic's electrical graph to build a hypothesis from topology (which rails feed what, in which order), and tells you explicitly when it's reasoning beyond the established rules.
Are my measurements kept?
Yes, every reported reading is logged in the repair journal: value, target, timestamp. You can compare before/after rework, and the confirmed cause at the end of a session enriches the device's knowledge for the next boards.
Is this motherboard test software?
Not in the usual sense. Test software and plug-in diagnostic cards need a board that still boots, and they hand back a code for the stage that failed. WrenchBoard starts on the board that shows nothing at all. And it is not limited to computer motherboards: any electronic board you have a boardview or a schematic for (laptop, phone, audio gear, industrial controller), whatever lands on your bench. It works down to the component, from the schematic's electrical graph and an ordered multimeter protocol, and names the part to replace. Not an error code, measurements.
Get started
Try Wrench Board free, in your browser.
Free plan, no card required. Open the app, pick a covered device, and start a diagnostic session with the agent.