The S-series platform: S6 architecture and the signal path of this machine
Identify the SonoScape portable in front of you, name the boards and units of the S6 and what each one does, and follow an echo from the probe element to the pixel, knowing where this family differs from the generic scanner of us-l1.
One family, one reference machine
The SonoScape S-series portables, the S2, S6, S8 and S9, are laptop-style colour Doppler scanners that sit on a docking cart or travel in a case. This course uses the S6 as its reference machine because its service manual is the one we work from. The other members of the family, and the newer SonoScape lines that followed, are built on the same idea: an ultrasound front end that forms the beams, a PC back end that runs the scanner software on a hard disk, and a data link between the two. Board names, screen sizes, the operating system release and the power arrangement differ from model to model, so whenever you work on anything other than an S6, take the details from that model's own documentation and use this course for the method.
In us-l1 you learned how any scanner is built and how a probe turns voltage into sound and back. That is not repeated here. This course adds what is specific to this machine: which board does which job, how they talk to each other, what the built-in test software can tell you, and how these machines actually fail in the field.
Start every job by establishing exactly what you have. Read the data plate for model and serial number. Then open System Information from the system menu: it shows the software version and the control number. The control number is unique to each machine, and the manual ties it to the serial number of the DBF board. Write both down. Software update files are issued for a model, a version and a control number, so you cannot plan any software work without them. Note also the probes, the options fitted (for example a function activated with a USB dongle inside the machine), the printers, any network or workstation connection and whether the unit lives on a cart.
The front end: probe board and the ultrasound module
The probe connects to the MPC board, which the manual also calls the probe board. It carries the two probe sockets and the relays that select which probe is active: two probes can be connected, but only one scans at a time. Through its large connectors the MPC board passes the element signals and the probe identification code to the DBTR board, and takes the supply for its relays and logic from the power side. That split matters in fault-finding, as you will see in lesson 4: a bad signal connection gives dark bars or an unrecognised probe, a bad power connection gives a probe that cannot be detected or switched.
Behind the MPC board sits the ultrasound module: three boards stacked in one bracket under a metal shield. The DBTR board is the transmit and receive analogue board. It synthesises the transmit pulses that drive the elements and carries the receive preamplifiers and TGC. The DBF board converts the echoes to digital, performs the digital beamforming with dynamic receive focusing, demodulates, extracts the Doppler information and contains the scan controller and the front-end controller. It also holds the USB interface that connects the whole front end to the PC. The DBHV board makes the high voltage for the transmit pulser and the low voltages for the analogue and digital circuits of the module; on the S6 it also carries the ECG and the drive for a mechanical 4D probe motor.
Think of the stack as a chain: DBHV powers, DBF commands and digitises, DBTR fires and amplifies, MPC routes. Most image faults on this machine are a question of which link in that chain has failed, and the manufacturer's test software is built around exactly that question.
The back end: a PC that runs the scanner
The PC motherboard is the central control unit. It runs the Linux-based system software from a SATA hard disk (160 GB on the S6), receives the processed echo data from the DBF board over a USB 2.0 connection, builds the image, drives the display and the audio, reads the keyboard and trackball and sends the user's settings back to the front end over the same USB link. Ethernet and the external USB ports are on the PC side too. The internal memory modules, the CPU fan and the SATA connection are all ordinary PC parts, and they fail the way PC parts fail.
The KEAA board is the interconnection hub. It distributes power and signals between the motherboard, the keyboard, the fans, the side input-output panel, the foot switch and the video printer control. Its connectors look alike, and the manual warns that they are easily swapped; photograph them before you unplug anything.
The display is a 15-inch medical LCD fed over an LVDS cable from the motherboard, with a separate voltage inversion board that makes the high voltage for the backlight. The side panel carries audio out, S-Video, two USB ports, Ethernet and VGA; the rear panel carries the two probe ports, the video printer control port, the foot switch socket, video out, the ECG socket, the equipotential earth point, the mains switch and the mains inlet. An external VGA monitor is the cheapest diagnostic tool you have for this machine: it separates a display fault from a PC fault in one minute.
Power: one medical supply, one high-voltage board
On the S6 all power comes from a medical switching power supply of the ATX type, which provides 12 V and 5 V DC to the rest of the system. The DBHV board then makes what the front end needs, including the 90 V DC for the transmit pulser. The supply and the mains switch come out as one unit. The PC is started by the side power button, whose wires go to the motherboard; the mains switch at the rear switches the whole machine off, but for work inside the cord is also unplugged, as lesson 5 describes.
The current for the entire ultrasound module passes through two power connectors on the DBHV board. The manual singles them out: a poor contact there raises the resistance, drops the voltage to the module and can burn the connector. Pull them by the housing, never by the wires, and look at them every time the module is out.
The S6 service manual describes a mains-powered system and does not describe an internal battery. Some later portables in the S-series and in newer SonoScape lines can carry a lithium-ion battery. If yours does, its type, charging behaviour, storage and replacement come from that model's documentation, and you treat it as a second energy source that stays live after the mains plug is pulled.
The manual also asks for the equipotential point at the rear to be connected to earth, not only for safety but because the image quality suffers without it. A machine that shows noise only in one room, on one socket, is a grounding question before it is a board question.
User interface and the cart
The keyboard assembly is built on the KBD board with a small auxiliary board, the trackball, the TGC sliders, the flip switches, the knobs, the silicone rubber keypads and the two loudspeakers that play the Doppler audio. To the PC, the keys and the trackball are ordinary input devices. That is why a keyboard fault on this machine can look like something else entirely: the manual warns that an abnormal start-up screen, or a machine that enters a diagnostic mode by itself, usually means a stuck or faulty key, and it tells you to test the keyboard before you look further. The case at the end of this lesson shows how far that can go.
The docking cart is part of the system in daily life. Wheels locked during use, the system powered off and unplugged, probes disconnected and stowed and peripherals removed before it is moved: these are the manual's rules, and they are also the cheapest protection against the connection faults that a frequently moved portable collects.
From element to pixel, and what is specific here
Follow one line of the image. The DBF board holds the transmit sequence and passes it to the DBTR board, which fires the selected elements through the MPC relays with high voltage from the DBHV board. The echoes come back through the same path, are preamplified and given TGC on the DBTR, then digitised, beamformed and demodulated on the DBF. The data goes to the PC over USB, the software scan-converts and displays it, and the PC sends the next set of controls back down the same link.
Compared with the generic scanner of us-l1, five things are specific and worth remembering. First, the front end and the back end are joined by a USB 2.0 data link, so a bad front-end connection often looks like a software crash, an automatic shutdown or a hang during loading. Second, the software and its configuration are tied to the identity of the machine through the control number, and hard disks are not interchangeable between models. Third, the DBF board appears again and again in the manual's fault table, because it does the digital work and owns the link. Fourth, the keyboard is a PC input and can disturb start-up and imaging. Fifth, the machine has its own test software that checks the chain board by board, which is the subject of lesson 2.
| Part | What it does | How it fails | |
|---|---|---|---|
| 01 | MPC board (probe board) | Two probe sockets, relays selecting the active probe, probe code to DBTR | Bad contacts or cold joints, relay or power fault, probe not detected |
| 02 | DBTR board | Transmit pulse synthesis, receive preamplifiers and TGC | Dark near field, dark bands, colour artefacts on some probes |
| 03 | DBF board | A/D, digital beamforming, demodulation, scan control, USB link to PC | Freeze or reboot during loading, line and mirror artefacts, wrong probe icon |
| 04 | DBHV board | Transmit high voltage (90 V DC), low voltages, ECG and 4D motor drive | Dark or shallow image, frequent crashes, burnt power connectors |
| 05 | PC motherboard with RAM | Runs the Linux system software, image display, audio, Ethernet, USB | Black screen, no start, auto shutdown; RAM and CPU fan are wear points |
| 06 | Hard disk (SATA) | Holds operating system, scanner software, presets, images and patient data | Slow or failed boot, file system errors, total failure |
| 07 | KEAA board | Hub for power and signals: keyboard, fans, side IO panel, foot switch, printer control | Swapped look-alike connectors after repair, loose cables |
| 08 | Power unit (medical SMPS with mains switch) | 12 V and 5 V DC to all units; replaced together with the mains switch | No power, auto shutdown or restart on key press, poor contacts |
| 09 | LCD and voltage inversion board | 15-inch display via LVDS; inversion board drives the backlight | Dark or distorted screen, colour changes; check with external VGA first |
| 10 | Keyboard assembly (KBD board, trackball, keypads, speakers) | User input to the PC and Doppler audio output | Stuck or dirty keys, worn trackball, unresponsive keys, odd start-up |
A triple image caused by a key
A SonoScape portable came in with a tripled image: on the convex and the linear probe every structure appeared three times across the sector. The third probe showed no artefact. The engineer first suspected the probes, then the switching board, reasoning that one address bit of the beam number was not getting through. Colleagues discussing the case kept asking about the keyboard. The cause turned out to be a stuck key on the control panel. Freeing it cured the image on both probes, and no board was replaced.
On this family the keyboard is a PC input that changes imaging settings. When an image fault depends on the preset or probe in a strange way, run the key test and look at the keys before you condemn a probe or a front-end board.
A failing video chip on a SonoScape
Engineers discussed a SonoScape scanner whose video output had failed because of a degraded graphics chip. Someone suggested heating the chip, as is often done with laptops. Others advised against it: the effect of reflow is unpredictable, and the chip had not lost its solder joints but had degraded from long overheating. One engineer had already met the same fault on a SonoScape and had solved it by replacing the graphics card with an equivalent one. The discussion ended with two sound options: replace the chip with proper rework equipment, or replace the graphics card.
The back end of these scanners is a PC and its parts age like PC parts, mostly from heat. Repair the video path properly, then deal with the cooling that killed it, or the new part will follow the old one.
On-site checklist
- Model and serial number recorded from the data plate
- Software version and control number recorded from System Information
- Probes listed with serial numbers and which port each normally uses
- Options and any internal dongle noted; peripherals and network connections listed
- Equipotential earth point connected and mains socket checked
- Cart wheels lock and the machine is moved powered off, probes stowed
- Service documentation for the exact model at hand (S6 or other S-series)