Kove Audio ZD2000V amplifier schematic?

[Briareus]

Hi everybody,
I have a Kove Audio ZD2000V car amplifier that I am trying to repair. Amplifier powers up with protection light on. I've narrowed it down to the power supply section and needing help. Anyone with schematic or troubleshooting ideas please help.

[Perry Babin]

If no one can help, post a photo of the board. It may be a clone of an amp that has a schematic diagram that's readily available.

[Briareus]

Finally got a chance to check back in. Did find some cold solder joints and I think the two large capacitors are bad. But here is a pic.

[Perry Babin]

Generally, when an amp goes into protect mode, the fault is in the audio section. How did you determine that the problem is in the power supply?

Where were the bad solder connections?

Does the power supply try to power up when you apply remote voltage?

[Briareus]

Here's another close up pic of power supply side. Black arrow indicates loose coil. The red side voltage is 1/10th the voltage of the blue side on the 3205's gate pin. I don't have an oscilloscope so all my testing is with a simple multimeter. Not sure if getting right signal from KA7500B controller either. I took the amp to a local repair shop and they confirmed that the power supply was not turning on, but said that without a schematic they couldn't track down the problem without another $200 in labor.

[Perry Babin]

Post the DC voltage on all pins of the KA7500. Copy and paste the following into your post.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:

[stocktrader200]

I believe KA7500 and TL494 are interchangable
had one in an old power supply

[Briareus]

source voltage measured 14.65
Pin 1: 8.44
Pin 2: 2.52
Pin 3: 4.61
Pin 4: 3.75
Pin 5: 1.5
Pin 6: 3.64
Pin 7: 0.0
Pin 8: 14.65
Pin 9: 0.0
Pin 10: 0.0
Pin 11: 14.65
Pin 12: 14.65
Pin 13: 4.94
Pin 14: 4.94
Pin 15: 4.94
Pin 16: 0.0
found a manufacture date of 2003. ran a soldering iron over the spots I thought might be a loose connection and retested with no difference. hopefully this weekend I can get the two 4700uf caps out and checked. saw no leakage but the tops are domed and soft.

thanks for all the help, I DO really appreciate the help!

[Perry Babin]

It appears that the amp is in protect mode. Post the DC voltage on the pins of the 8-pin op-amp adjacent to the ka7500.

The FETs on both sides should have had essentially 0v DC on their gates with the voltages you posted.

[Briareus]

Took my measurements there. It is a LM393N.
Pin 1: 9.11
Pin 2: 4.30
Pin 3: 14.20
Pin 4: 0.0
Pin 5: 4.37
Pin 6: 4.40
Pin 7: 9.07
Pin 8: 14.72
Source voltage is 14.75v
Also checked voltages at the capacitors in power supply. I had source V coming into all the smaller caps near input. Did not have anything at the 2 large ones by the large coils.