Rencheng Repair Case: Analysis of Automatic Power-Off Failure in Philips IE33 Color Ultrasound Machine

Machine Type: Philips color Doppler ultrasound diagnostic instrument

Machine Model: Philips IE33

I. Fault Phenomenon

The doctor reported that the machine automatically powered off during patient examination after powering on.

II. Fault Analysis

1. Suspected motherboard overheating protection;

2. The fault remained after dust removal from the motherboard and cleaning of the filter net;
3. Inspecting the image signal processing host computer motherboard, two 6.3v, 3300uf electrolytic capacitors were found bulging near the memory slot. Replaced with two 10V, 3300uf electrolytic capacitors;

4. The machine hardware initialization could not pass at step 41, with error code 606;

8. There is a communication board on each slot of the motherboards on both sides of the host, and the signal indicator lights are flashing, indicating that the communication board is normal. Therefore, it is suspected that the insufficient memory of the image signal processing host caused the hardware initialization failure and error report;
9. Since it's a DDR generation memory bar, a 256Mb DDR memory bar was found in an old computer and installed, still reporting error 535;
10. Still suspecting insufficient memory, the memory bar from the left HOST of this ultrasound machine was removed and installed into the right image signal processing (SIP) host. The machine reported error 602, which is estimated to be caused by insufficient memory in the left HOST host;
11. The memory bars were restored, and the machine initialization was successful after restarting.

12. At this time, after entering the application software, there was an echo signal. However, after one minute, the echo signal suddenly disappeared, and the machine automatically shut down after one second!! It returned to the initial fault phenomenon!

13. However, a detail was discovered at this time: the automatic shutdown occurred after the echo signal disappeared. At this time, it is suspected that it is not the motherboard overheating protection of the image signal processing host, but the power overcurrent protection.
14. Considering the phenomenon of the echo signal disappearing, it is suspected to be a high-voltage fault. Since there is still an echo signal initially after powering on, it can be determined that it is caused by the carbonization short circuit of the high-voltage part causing power overcurrent protection. This situation has been encountered many times in long-term repair practice, all due to long-term poor contact of the connectors causing heat generation, which then causes carbonization of the connectors, and finally causes short circuit failure.
15. The front-end channel board was disassembled, and the four connectors were removed and checked separately, and the connector on the far right was found to be carbonized and burnt!

16. Because the connector is not available for replacement, the burnt part of the connector can only be cut off, and the plug and socket are directly welded using the power cord;

17. Since the short circuit was caused by the long-term poor contact and heat generation and carbonization of the connector, in order to avoid this fault from occurring again, we used rust remover to rust and deoxidize the four connector plugs and sockets.

18. Memory bars that have been previously ground with a blunt tool will certainly oxidize quickly, causing poor contact and causing the machine to report errors again. Therefore, multiple spare DDR512Mb or larger generation 1 memory bars will be needed in the future.
19. After installing and starting the machine, the machine returned to normal. After three days of use, the machine is still working normally. The repair is complete, and the machine is under observation!

III. Summary and Review
1. Fault details are very important;
2. The IE33 ultrasound machine cannot complete initialization with less than 2G of memory on both sides of the host, resulting in communication errors;
3. IE33 ultrasound machine normal power-on prompt: a long beep followed by a short beep.