Like the title says, I have a Hifonics BRZ1700.1D that I got from a friend of mine and he told me it was not working. I then bench tested the amp and the green power indicator led and the blue illuminated LEDs on the top of the amp came on. When I proceeded to plug in my RCAs and a subwoofer, there was absolutely no sound. I hear a click from the relay that is inside the amp and there is no output. No matters what setting I adjust still nothing. I looked inside the amp and nothing is burnt or out of the ordinary. Any help? These amps also have the same boards as the BXI2010D. Thanks in advance!
I can do testing with a dmm if needed. I havve repaired numerous amps in the past but only a few class d amps so i dont want to mess this up.
I would also check the power supply fets in the amp to see if any are shorted Ive seen tons of theese amps with blown power supply's and the greeen led still light up..
Ok sorry for the delayed response. I had go take my mom to the store. When i just pulled the board out of the heatsink? I noticed some burnt power transistors and tested the resistance of all of them and they seem to be different. I will be changin these soon along with the gate resistors. Then i tested the resistance of the output transistors and most of them seem to be around the same range which is about 4. Could the power transostors ne whats causing my problem?
For clarity...
All of the transistors clamped to the heatsink are 'power transistors'. The FETs that drive the power transformers should be referred to as 'power supply transistors' or 'power supply FETs'.
When you post measurements/readings, you need to include the units. '4' doesn't tell us much. It could be 4 ohms or 4M ohms.
All of the transistors clamped to the heatsink are 'power transistors'. The FETs that drive the power transformers should be referred to as 'power supply transistors' or 'power supply FETs'.
When you post measurements/readings, you need to include the units. '4' doesn't tell us much. It could be 4 ohms or 4M ohms.
Sorry about that. I tested the resistance of the power supply FETs and most of them had different readings such as 4ohms down to no resistance at all or (oL) on my Dmm. The output transistors and each of them gave around the same reading which was about 4ohms to 4.5ohms. I assume those are ok and will just have to change out the power supply FETs and gate resistors and see what will happen. Lastly, the numbers on the transistors are P75NF75 with a symbol that looks like either a 8 or &. Can you recommend me to any reliable places online that sell these FETs?
If you read anything as low as 4 ohms between the legs of any individual transistor in the output section, there are definitely defective transistors.
In most of the hifonics amps I use the IRF3205 FET with 47 ohm gate resistors and the BD139 and BD140 for the driver transistors.
There are other problems that you should be prepared for with this amp. I'd sugest that you order the TL072 op-amps to replace the ones on the driver board which sometimes fail. I'd also recommend that you order at least 10 of the MMBTA42 and MMBTA92. There are some on the audio driver board that commonly fail as well.
In most of the hifonics amps I use the IRF3205 FET with 47 ohm gate resistors and the BD139 and BD140 for the driver transistors.
There are other problems that you should be prepared for with this amp. I'd sugest that you order the TL072 op-amps to replace the ones on the driver board which sometimes fail. I'd also recommend that you order at least 10 of the MMBTA42 and MMBTA92. There are some on the audio driver board that commonly fail as well.
I have finally had a little bit of time to check over things with this amp.The amp almost certainly has a blown power supply because when I recieved the amp, five out of six power FET's on one side of the board had blown gate resistors and only two of the FETs were actually burnt up.
The weird thing about this though is that the trace on the circuit board for the relay was stripped off of the board in a place (about 1cm of a break) and this caused to make the amp go into protect. I made a little jumper out of copper wire to repair this and now when power, remote, and ground are connected, the amp will turn on (green led) but no output, even though the blown power FETs are still in.
Could there be anything else wrong? I have not really tested anything else and I can as soon as I get a new dmm. Also, you said you recommend IRF3205 Fets to replace the current power FETs wih 47ohm gate resistors. Also, you said to change the driver transistors to BD139 and BD140. Where are the driver transistors located? (sorry for the noob question) I have also changed the op-amps on the output driver card (TL072) and will change the the smaller MMBTA42 and MMBTA92 on the output driver card as well. Thanks in advance! Just wanted to get as much details in so I could try to fix this amp.
The weird thing about this though is that the trace on the circuit board for the relay was stripped off of the board in a place (about 1cm of a break) and this caused to make the amp go into protect. I made a little jumper out of copper wire to repair this and now when power, remote, and ground are connected, the amp will turn on (green led) but no output, even though the blown power FETs are still in.
Could there be anything else wrong? I have not really tested anything else and I can as soon as I get a new dmm. Also, you said you recommend IRF3205 Fets to replace the current power FETs wih 47ohm gate resistors. Also, you said to change the driver transistors to BD139 and BD140. Where are the driver transistors located? (sorry for the noob question) I have also changed the op-amps on the output driver card (TL072) and will change the the smaller MMBTA42 and MMBTA92 on the output driver card as well. Thanks in advance! Just wanted to get as much details in so I could try to fix this amp.
^That's what I meant by paragraph breaks and blank lines^
Are you saying that you haven't yet replaced the power supply FETs?
The drivers are probably designated as Q7, Q8, Q7A and Q8A.
I have removed the ones that appeared to be blown and the ones with fried gate resistors as well. That is only on one side though. The other side appears fine, nothing burnt, etc.
Is is normal for something like this to happen(not going into protection)?
The amp still turns on, relay clicks, and no output. I have confirmed this as I have tried two different amplifiers in its place with the exact same connections.
Is is normal for something like this to happen(not going into protection)?
The amp still turns on, relay clicks, and no output. I have confirmed this as I have tried two different amplifiers in its place with the exact same connections.
What is the circuit board designation for the blown transistors?
Do you have rail voltage on the center legs of the rectifiers?
Do you have regulated voltage on the power supply pins of the op-amps?
Do you have rail voltage on the center legs of the rectifiers?
Do you have regulated voltage on the power supply pins of the op-amps?
The designations for the power FETs are Q9-20.
The voltages I will take tomorrow as I do not have a dmm with me right now.
The voltages I will take tomorrow as I do not have a dmm with me right now.
sorry. Q19 and Q20 were the ones with visible damage. Q16,17,19 had fried gate resistors though. Does that mean those are bad too?
You have to replace all 6 FETs on that power supply (Q15-Q20).
It is VERY rare that one supply survives for two reasons.
* With one supply out of the circuit (blown) the remaining supply fails because all of the load is put on the remaining power supply.
* Secondly, both supplies use the same drivers. When one supply fails, it often destroys the drivers. With the drivers destroyed, the second supply cannot function properly or fails because the FETs can no longer be driven properly.
It is VERY rare that one supply survives for two reasons.
* With one supply out of the circuit (blown) the remaining supply fails because all of the load is put on the remaining power supply.
* Secondly, both supplies use the same drivers. When one supply fails, it often destroys the drivers. With the drivers destroyed, the second supply cannot function properly or fails because the FETs can no longer be driven properly.
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