I got 4 free Kenwood KAC-51 that do not work. All four have made 2 fets burnt all in the same location.
After replacing the 2 fets and gate resistors I turn it on but only get a loud humming noise. My Oscillator shows a square wave but jumps up and down.
Im hopping if I can fix this one with your help the other 4 will have the same fix or close to it.
Thank
After replacing the 2 fets and gate resistors I turn it on but only get a loud humming noise. My Oscillator shows a square wave but jumps up and down.
Im hopping if I can fix this one with your help the other 4 will have the same fix or close to it.
Thank
No I have not but if you asked it must be a good thing a will do tomorrow.
Here is the video and audio.
Here is the video and audio.
OK. One amp per thread.
Using a 494 for the PS?
What are they using for the output driver ICs?
Did you confirm that the PS drive was OK with a loading capacitor before installing the replacement FETs?
Using a 494 for the PS?
What are they using for the output driver ICs?
Did you confirm that the PS drive was OK with a loading capacitor before installing the replacement FETs?
Oh, I didn't know about the 1 amp per thread and I thought you wanted me to because you asked "Did you try more than one amp?" sorry will not happen again.
Q: Using a 494 for the PS?
A: yes
Q: Did you confirm that the PS drive was OK with a loading capacitor before installing the replacement FETs?
A: I tested everything that I know how to but not sure I know how to test "with a loading capacitor before installing the replacement FETs".
I would really appreciate it if you can explain how to. Thanks
Q: Using a 494 for the PS?
A: yes
Q: Did you confirm that the PS drive was OK with a loading capacitor before installing the replacement FETs?
A: I tested everything that I know how to but not sure I know how to test "with a loading capacitor before installing the replacement FETs".
I would really appreciate it if you can explain how to. Thanks
TT9, item 23 if you have the tutorial has much more information. Get the latest version if your doesn't have all of the simulated waveforms. There are 13 images in section 23.
You won't use the header shown with SMD FETs but the test is the same. You connect a capacitor across the gate and source terminals to see if the drive circuit is driving to ground as it should. With no load, the current capacity of the drive could be compromised without it showing on a scope. It would look like a perfect square wave. With the load, a good circuit will look like the waveform below. A defective driver circuit wouldn't be able to pull back down to ground as is shown below.
Since the SMD FETs may be difficult to remove, connect a resistor or jumper wire across their gate and source to keep them from passing current. Remove the gate resistors and load the output of the driver IC (where it connects to the gate resistors, after any drivers) with a capacitor (0.1uF - 0.01uF) and a 47 ohm resistor. One terminal of the capacitor would be connected to ground. Check the waveform on the ungrounded terminal of the capacitor.
You won't use the header shown with SMD FETs but the test is the same. You connect a capacitor across the gate and source terminals to see if the drive circuit is driving to ground as it should. With no load, the current capacity of the drive could be compromised without it showing on a scope. It would look like a perfect square wave. With the load, a good circuit will look like the waveform below. A defective driver circuit wouldn't be able to pull back down to ground as is shown below.
Since the SMD FETs may be difficult to remove, connect a resistor or jumper wire across their gate and source to keep them from passing current. Remove the gate resistors and load the output of the driver IC (where it connects to the gate resistors, after any drivers) with a capacitor (0.1uF - 0.01uF) and a 47 ohm resistor. One terminal of the capacitor would be connected to ground. Check the waveform on the ungrounded terminal of the capacitor.
Attachments
I have the updated tutorial and will start reading ASAP.
After I read and under stand I will test the amplifier and get you the info.
Thanks for the help Perry.
After I read and under stand I will test the amplifier and get you the info.
Thanks for the help Perry.
To be clear, updated means yesterday since there are revisions every day. I've been cleaning up some old graphics and adding a few more for the last few days. If you have 13 images there. That's good enough for now.
For others that have not updated in a while, it costs nothing. Get updates t least once a month if you use the information on a regular basis.
For others that have not updated in a while, it costs nothing. Get updates t least once a month if you use the information on a regular basis.
1. I was unaware that revisions occur daily; the last update I received was quite some time ago. How would you prefer me to provide my email address and IP address, assuming that is still the method you use?
2. I believe I have identified the issue, or at least part of it. By comparing the diodes, specifically A1, which I think is an IN4001, with a functioning one, I noticed that the yellow diode shows 0 reverse voltage from Gate to Ground. Additionally, when testing the blue arrow for the other two FETs, the diode from Gate to Ground measures .5880. I conducted the reverse testing using a diode tester with the negative lead on the Anode and the positive lead on the Cathode. Please let me know if my explanation is unclear.
2. I believe I have identified the issue, or at least part of it. By comparing the diodes, specifically A1, which I think is an IN4001, with a functioning one, I noticed that the yellow diode shows 0 reverse voltage from Gate to Ground. Additionally, when testing the blue arrow for the other two FETs, the diode from Gate to Ground measures .5880. I conducted the reverse testing using a diode tester with the negative lead on the Anode and the positive lead on the Cathode. Please let me know if my explanation is unclear.
Attachments
1. Email me. babin_perry@yahoo.com
2. Some meters read 0 when voltage is present in diode-check mode. Did you get a 0 reading with the probes reversed? If it's reading 0 both ways, it's likely shorted.
They're unlikely to use a 4001 in a switching circuit. It's too slow and would overheat. The resolution was too low for me to see the diode package. What is it?
Output driver ICs?
2. Some meters read 0 when voltage is present in diode-check mode. Did you get a 0 reading with the probes reversed? If it's reading 0 both ways, it's likely shorted.
They're unlikely to use a 4001 in a switching circuit. It's too slow and would overheat. The resolution was too low for me to see the diode package. What is it?
Output driver ICs?
I have yet to discover a method for obtaining an IP address with CG-NAT so I can download the updates, but I am still looking for a solution.
I did placed an order for the A1 (4001) as you recommended, and I have successfully fixed it.
Thank you for your help.
I did placed an order for the A1 (4001) as you recommended, and I have successfully fixed it.
Thank you for your help.
It is T-Mobile. Eventually, all users will transition to CG-NAT due to the depletion of available IP addresses by ISPs. CG-NAT allows multiple users to share a single IP address, similar to how mobile phones operate. With an external MIMO antenna panel, I achieve speeds ranging from 300 to 415 Mbps, which is faster than any cable internet service available in my area. I plan to purchase a dedicated IP address from ExpressVPN and will send you an email with the IP they provide.