MS004/ MS002 test benches and a very useful function – F67

The MS004/MS002, which can be used to diagnose automotive alternators, voltage regulators and starters, have a wide range of diagnostic possibilities for a large number of units with different parameters.

Let's talk about one of the many useful functions (features) of these stands – it is the F67 function (the name comes from the designation of the brush connection terminal). This function is a voltage regulator built into the stand (MS004MS002), which provides a set (by the operator of the stand) voltage at the generator output, so it is possible to diagnose 12V generators without a voltage regulator.

One of the most vulnerable parts of an alternator – the voltage regulator. When the alternator inspection reveals its failure, most often the diagnostic process stops there, considering that the fault has been detected. The diagnosis is then resumed with a new voltage regulator, which is a mistake because it is necessary to check some of the reasons for the failure of the voltage regulator:

• short circuit in the circuit, including interturn short circuit of the field winding;
• rectifier bridge malfunction (diode breakdown).

If these failures are present in the generator being diagnosed, then installing a new voltage regulator, there is a high probability of ruining it, especially if the diagnosis is carried out at high load values.

Therefore, if a faulty voltage regulator is found in the alternator, it is better to first diagnose the rest of the alternator using the inbuilt voltage regulator function (F67).

If no abnormalities are detected, it is safe to install a new voltage regulator and run the diagnostics with it to make sure that the alternator is working correctly again.

The MS004 MS002 automotive starter, alternator and voltage regulator diagnostics equipment allows you to perform a quality diagnosis of these units without the need for additional measuring equipment.