Hello
I owner Hifonics ZEUS ZX4000 from Russia. Recently, a clipping in one of the channels. Unfortunately, in Russia there is no official representation Hifonics. There is no service.
I contacted the Maxxsonics and Audiodesign, but they refused to help me with send the service manual for this amp. No one wanted to help and get in my difficult situation.
I got in touch with the people in Russia who are engaged in service Hifonics before, but they did not have the service manual for this amp. I do not know what to do ... I love this amp and I would like to use it on, but I can not fix it without a schema.
Send to repair to Germany is very expensive for this device.
If anyone has friends in the any service center, who repairing Hifonics amps, please ask them for a service manual, or at least one sheet with full circuit diagram for ZX4000.
Thanks a lot anyway.
Alex.
I owner Hifonics ZEUS ZX4000 from Russia. Recently, a clipping in one of the channels. Unfortunately, in Russia there is no official representation Hifonics. There is no service.
I contacted the Maxxsonics and Audiodesign, but they refused to help me with send the service manual for this amp. No one wanted to help and get in my difficult situation.
I got in touch with the people in Russia who are engaged in service Hifonics before, but they did not have the service manual for this amp. I do not know what to do ... I love this amp and I would like to use it on, but I can not fix it without a schema.
Send to repair to Germany is very expensive for this device.
If anyone has friends in the any service center, who repairing Hifonics amps, please ask them for a service manual, or at least one sheet with full circuit diagram for ZX4000.
Thanks a lot anyway.
Alex.
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Top side
https://www.dropbox.com/s/cnm7w6rsmc2vpj7/2012-12-15 16.33.47.jpg
Bottom side
https://www.dropbox.com/s/zx53zk8pf687kqt/2012-12-15 17.19.17.jpg
All I have for now
https://www.dropbox.com/s/cnm7w6rsmc2vpj7/2012-12-15 16.33.47.jpg
Bottom side
https://www.dropbox.com/s/zx53zk8pf687kqt/2012-12-15 17.19.17.jpg
All I have for now
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Have you tried operating all of the pots and switches through their entire range to see of the distorted channel ever plays through cleanly?
Have you tried swapping the RCA inputs to confirm that the problem is not the input signal?
What are you using to trace the signal through the amp to see where it becomes distorted?
What's the number on the 8-pin IC in the center of the board between the large white resistors?
Have you tried swapping the RCA inputs to confirm that the problem is not the input signal?
What are you using to trace the signal through the amp to see where it becomes distorted?
What's the number on the 8-pin IC in the center of the board between the large white resistors?
1. Yes. Now I desolder all pots except gain.
2. Yes. Other amps play clear.
3. Only my ears.
4. It's OpAmp BA4558. (I haven't other one in DIP8 case for change and check)
So for quality repair better way is get schematic...
Even with a diagram, you'd have to be able to trace the signal though the amp to determine where it becomes distorted.
Thank you. I know this. But I need to know where I need to check it.
Manual tracing is to hard for me. And services do not take it for repair without schematic.
Manual tracing is to hard for me. And services do not take it for repair without schematic.
I think problem in voltage amplifier.
I have 15 mV on resistors (4.7 Ohm) in base all output transistors and in one channel I have not voltage on resistor (220 Ohm) between shoulders ("+" and "-"), but in other channel I have 18 mV on same resistor.
And... is it not very low "Ibe" in bases? It is 0.15/4.7=0.032mA...
I have 15 mV on resistors (4.7 Ohm) in base all output transistors and in one channel I have not voltage on resistor (220 Ohm) between shoulders ("+" and "-"), but in other channel I have 18 mV on same resistor.
And... is it not very low "Ibe" in bases? It is 0.15/4.7=0.032mA...
Solved the problem with the noise.
It was in bad solding jumper between the amplifier output voltage and one of the output stage transistor.
But I have another problem. I need to set the quiescent current of 60 mA.
But I can not find this resistor without diagram 🙁
Can you tell where it should be?
As I understand it at the amplifier input voltage...
Sorry for calculate. True is: 0.015 v/4.7 ohm=0.0032 A, so Ibe=3.2 mA ... it is really near Class B.
Transistors are cold. It is to bad for sound. I need Ibe = 60 mA.
It was in bad solding jumper between the amplifier output voltage and one of the output stage transistor.
But I have another problem. I need to set the quiescent current of 60 mA.
But I can not find this resistor without diagram 🙁
Can you tell where it should be?
As I understand it at the amplifier input voltage...
Sorry for calculate. True is: 0.015 v/4.7 ohm=0.0032 A, so Ibe=3.2 mA ... it is really near Class B.
Transistors are cold. It is to bad for sound. I need Ibe = 60 mA.
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So, I measured the AC voltage at the output emitter resistor, it is without IN signal at 0.5mV. Resistor 0.1 ohm / 5W. Emitter current only 4.5 mA, which is very small and tranistory work practically in a class B.
I can not find resistors adjust the quiescent current.
Help me find them, please!
I can not find resistors adjust the quiescent current.
Help me find them, please!
Where did you get the bias current of 60ma?
You measure the DC voltage across the emitter resistors, not the AC voltage.
Most amps without bias pots are class B amps.
You measure the DC voltage across the emitter resistors, not the AC voltage.
Most amps without bias pots are class B amps.
Sorry, yes, DC and yes - Class B.
Actually I found current regulator resistor.
But try to set 60 mA yet...
Actually I found current regulator resistor.
But try to set 60 mA yet...
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