What is the problem that the relay of the professional power amplifier delay start circuit does not

1. The power amplifier board has damaged components or poor contact, resulting in excessive midpoint voltage.

2. The working voltage of the power amplifier board is abnormal, and the large difference between positive and negative voltages will also cause the midpoint voltage to be too large.

3. If there are components in the protection circuit, the damage will also make the relay not engage.

4. The working voltage of the delay circuit is abnormal, and the suction voltage value of the relay cannot be reached, it may be that the components are broken or the circuit board is greasy and dirty, and the circuit will be abnormal.

5. The relay is broken. However, it is necessary to measure the voltage of the control terminal of the relay first, and if the voltage is normal and does not engage, it can be determined.

In short, there are many reasons, to gradually eliminate, it is best to unplug the power cord of the power amplifier board first, to see if the relay can be engaged, if it can be attached, you can determine that the delay circuit is normal, it may be the power supply or power amplifier board failure.

The delay relays of the amplifiers are designed to protect the horn.

There are only two reasons why the relay does not engage, one is the zero drift in the power amplifier output circuit, simply put, there is a DC component (DC voltage) in the power amplifier output, and the DC component will damage the speaker, so in order to protect the speaker, the relay does not engage, it is a problem with the power amplifier output circuit and needs to be repaired; Another reason is that there is a problem with the control circuit of the relay itself, which causes the relay to not engage, but this is unlikely.

The fault is the overload protection of the motor.

1. When the relay should be turned on, measure the input voltage, if the voltage is lower than the required operating voltage, indicating that there is a problem with the line in front of the SSR input terminal, if the input voltage is higher than the required operating voltage, check the power supply polarity and correct it if necessary.

2. Measure the input current of the SSR, if there is no current, it is an open circuit of the SSR, the relay is faulty, if there is a current, but it is lower than the action value of the relay, it is a problem with the line in front of the SSR, which must be corrected.

The power amplifier relay does not engage to check whether the control voltage of the relay is normal, if the voltage is normal and the relay is not engaged, it is a relay problem, if there is no voltage, it is necessary to check the relay control circuit first.

Check whether the circuit board components are burnt, blackened, etc., and whether the fuse is in good condition. If the main relay does not engage, check that the coil resistance and the main relay control circuit are normal. Then measure the L channel, the midpoint voltage of the L channel final stage power amplifier circuit is -12V, and it should be 0V under normal conditions.

The cause of the fault is that the voltage at the midpoint of the output terminal of L deviates seriously from the 0 point, resulting in the main relay not engaged. At this point, the fault range is narrowed down to the L-channel power amplification circuit.

If the output voltage and overcurrent detection voltage in the power amplifier circuit are normal, and the protection relay does not engage, the fault is in the protection circuit, and the relay drive integrated circuit or drive tube should be checked for damage and whether the detection circuit is normal. If the relay contacts can be engaged, but there is no sound output, you should first check whether the speaker is normal, whether the relay contacts are in good contact, and whether the noise suppression circuit is operational.

Focus on checking the main channel amplifier tube, midpoint, push, and differential.

Roughly judged, the control end of the power amplifier relay is not well insulated, check whether there is crosstalk.

Excuse me, what's the problem?

I also have one that has the same fault!! Thank you.

The non-engagement of the power amplifier relay is related to the midpoint potential shift (the offset is greater than 2V), but the fault of the related circuit of the relay is not ruled out. The midpoint voltage measurement point is located at the speaker wire. If it is a single power supply circuit, there is an output capacitor in series between the output and the speaker wiring, and the measurement should cross this capacitance, and directly measure the DC voltage of the output terminal of the circuit and the ground wire, and the normal value should be one-half of the power supply voltage.

Hello! One of my Japanese Tenron amplifiers only has one sound left, and the relay sometimes has a clicking sound.

If the relay does not engage, it means that the components of the final amplifier are damaged, for example, one or two channels have a triode leakage or even breakdown, resulting in the wrong center voltage. In order not to burn out the speaker (or demagnetize the speaker), the protection circuit kicks in.

To find the measuring point of the central voltage position, it is necessary to know the output pin of the amplifier tube. 1. The right tube is used, that is, the emitters of the two tubes are connected together by resistance, and it doesn't matter whether you are OCL circuit or OTL circuit, it is the same. 2. The last power amplifier tube is of the same model, and it will be the middle of the E pole + pole.

For OTL (with output capacitors) circuits, the center voltage is half of the supply voltage; The OCL is a zero-volt docking site.

The power supply string is about 40W no-load test machine (220V incoming line there), it will not smoke, but. I can't find the midpoint in **, this is difficult to repair. The relay has one set of coils, two sets of contacts, two of which are to the binding post, two are empty, and two are the midpoint).

If you don't understand, it's best to measure a few large power tubes. Look which side burned, and then take down all the parts over there and measure them.

When the OCL fails, the midpoint DC voltage will rise, and the DC voltage at the output end of the left and right channels is zero volts under normal sentimental conditions, when the power amplifier circuit is due to the fault of checking and amplifying or the midpoint voltage deviation when the power amplifier brother code tube breaks down and leakage, then the output end of the power amplifier will output a very high DC voltage, and this voltage is directly applied to the speaker, which will cause the speaker to burn out. Therefore, when the power amplifier protection relay does not engage, the first thing to measure is whether the midpoint voltage deviates, if the deviation needs to check whether the pre-amplification circuit is normal, whether the static working current of the final power amplifier tube is normal, if the midpoint voltage is normal, then the problem lies in the control circuit, you need to check whether the triode in the protection circuit is open S8050