Fault instance

Failure phenomenon 1

The Mindray 509 instrument has no SPO2 value and the probe observes no red light emission.

Analysis and overhaul

The probe does not emit red light and it is estimated that the probe is defective. Replace the standby probe SPO2 value back to normal to determine the probe failure. At the interface, the red light emitting section of the light emitting tube was found to be unblocked. The finger sleeve was disassembled, and the silica gel that fixed the transmitting seat cover was peeled off and measured at the root of the light emitting tube with the watch. The static value was normal. Estimate the front end break. Use a scalpel to carefully cut the joints of the cuffs, find a cable break, weld the cable, and apply the silicone to the seat cover. On the machine, the probe works normally. This probe is a common-mode probe. Similar to this kind of probe is rarely used, Mindray 507 instrument and Tianjin Di Tuo D T2100 monitor use this type of probe.

EEG machine

Symptom 2

The Dat e x - Tuff a st Oximeter has no SPO2 value and emits red light.

Analysis and overhaul

The photocell was found to be extremely insensitive to light. It was estimated that the photo-electricity was aging or the cable was disconnected. The finger sleeve was opened, and the receiving seat cover was removed. The phenomenon was still observed at the root of the photocell. Use a scalpel to carefully peel off the photocells encapsulated on the seat cover and solder the photocells of the probes on the same type of obsolete instrument. Seal them with 704 silica gel. Be careful not to reverse the photocell receiving surface. Upon completion of the test, the SPO2 value returned to normal. The probe is a common-type probe. Fewer probes like this, the author only found this one.

Failure phenomenon 3

HP HP5500A instrument SPO2 value display value is low.

Analysis and overhaul

Replace the standby probe with normal SPO2 value and make sure the probe is defective. After measurement, the static value of each part of the probe is normal. Doubt about the efficiency of the luminous tube or photocell. However, it was found that the probe tip had a hole. Blocking the hole SPO2 by hand returns to normal. It is estimated that the probe has light leakage, because the probe finger sleeve is made of soft silicone material, and it will be easily damaged if it is used for a long time. Find a soft silicone material with silicone to make up the hole. The probe is normally used and it has been used well so far. The probe is an AC probe. This type of probe is most widely used, such as the GE DASH-3000 monitor, the Milan 3500 monitor, the Dat ex anesthesia monitor, and the US KIN G PACE NP-900F ECG monitor. .