Cable harness repair on an ultrasound probe is delicate work for a specific reason: the cable is not one cable. Inside that sleeve run somewhere between 64 and 192 individually shielded micro-coaxial lines, each thinner than a human hair, each carrying one element’s signal. A single broken conductor takes out one element. Twenty broken conductors take out a wedge of your image. And because the break is usually a fatigue fracture rather than a clean cut, it opens and closes as the cable moves — which is why cable faults are the most misdiagnosed problem in the whole probe.
The signature: it changes when you move it
This is the one symptom that separates a cable fault from everything else. Dead elements in the array are dead all the time. A fractured conductor is a mechanical contact — flex the cable and the picture changes.
Scan a phantom or your own forearm, hold the image, and slowly work along the cable: bend it gently at the probe end, at the mid-span, and at the connector. Watch for vertical dropout lines that appear, disappear or shift. If the image flickers in step with your hand, the fault is in the cable or one of its two terminations.
Where they break
Almost never in the middle. Cable harnesses fail at the two places where a flexible thing is clamped to a rigid thing:
- The probe-end strain relief. The most common failure point on any probe. Every time the cable is pulled, hung over a hook or run over by a wheel, that transition takes the load. Look for a stretched, split or permanently kinked boot.
- The connector-end strain relief and the pins themselves. Dropped connectors bend pins. A bent pin can short to its neighbour, and this is the fault mode people underestimate: a shorted pin can take down the whole system, not just the probe — the machine trips its supply or refuses to power up, and nothing looks wrong from the outside.
If your system loses power or fails to boot with one particular probe connected, unplug it before you go looking for a system fault. That is a probe connector problem until proven otherwise.
Not every “cable fault” is the cable
Three things imitate a broken harness closely enough to send a healthy probe overseas:
- The system’s probe socket. If every probe fails to be recognised, suspect the socket board, not the probes. Try the same probe in a different port.
- A dirty or wet connector. Gel, disinfectant or condensation in the connector shell causes intermittent recognition that looks exactly like a cable break.
- The lens face. Dried gel and residue on the acoustic surface produce dark, patchy images that get blamed on the cable. Clean it per the manufacturer’s instructions and rescan before you go further — see lens and acoustic surface faults.
Send images before you send the probe
Most repair shops find out whether a damaged cable or connector is repairable after it has crossed a border. We do it the other way round: send us the on-screen images from your own system, a short video of the fault, and the model and part number. We assess it first.
If we judge it not repairable, we tell you not to ship it. That happens rarely — with this class of probe most faults are recoverable — but when it does, you have not paid freight, waited two weeks, or taken the probe out of service for nothing.
A phone call or an email thread is usually enough. What we need to see: the artifact as it appears on your machine, the probe’s behaviour when the cable is flexed, and any visible damage to lens, housing or connector.
How the repair is done
Two approaches, and which one applies depends on where the damage is. Where the break sits close to a termination, the harness is opened, the damaged section removed, and the conductors re-terminated — each micro-coax individually, matched to its original channel. Where the damage is distributed along the run, or where the sleeve has been crushed, the harness is replaced as a unit.
Bent or recessed connector pins are straightened or replaced individually; a shorted pin is isolated and its channel verified before the probe goes back on a live system. Every repaired probe is tested on a matching ultrasound system before it ships — a channel that passes continuity can still fail under signal.
Turnaround and shipping
Cable and connector work normally completes in about one week from arrival. You pay freight to send the probe; we ship it back free, whether or not the repair succeeded. Repairs carry six to twelve months of warranty depending on the probe and the work involved, confirmed with your quote — a fault that returns within that period is repaired free.
What the report tells you
For a harness repair the written report records which channels were open or shorted, what was re-terminated or replaced, and the post-repair test on a live system. A sample report is here. If your biomedical department needs the fault evidence for a service record, ask and we will include the before-and-after channel counts.
Frequently asked questions
How many broken conductors can be repaired before the harness needs replacing?
There is no fixed number — it depends on where they are. A dozen breaks clustered at one strain relief are a straightforward re-termination. Six breaks spread over a metre of crushed cable mean the harness is done. We tell you which case yours is once it is open.
The dropout only appears after the probe has been in use for twenty minutes. Is that still a cable fault?
It can be. Thermal expansion opens marginal fractures — a conductor that just makes contact when cold separates as everything warms. Mention the warm-up delay when you send images; it changes what we look for.
Can you repair the connector without touching the cable?
Yes, where the damage is confined to the pins or the connector shell. Bent pins, a cracked housing and a failed latch are all repaired in place. That is a shorter job than a harness repair.