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Zeptoplix 23rd January 2013 04:11 AM

Clarion Dpx11500 repair help
Hello All,

First post, and I'll do my best not to sound like a newb.

I've been reading quite a bit between this site and others online. Great resource for finding information about parts.

I have a Clarion DPX11500 amplifier that I bought for $50. I knew I was buying a dead amp. From my observation it was over driven with a poor ground which caused it to get hot enough to melt insulation. Various heat damage to components in various locations on the board. The ribbon cable going to the RCA board was actually charred as in fire damage.

Power supply was damaged, replaced all eight HUF75344G3 fets, as well as the 5.11ohm gate resistors.

This stabilized the amp enough to connect a fused power supply.

I have the service manual here, and have replaced a few parts that were visibly damaged. There are a dozen or so resistors on the board that are browned, but still measure fine. Others, not so much which I replaced. Same with diodes. There were a couple that were badly discoloured which I replaced. I replaced the ribbon cable.

I do have a knowledgable friend that has been helping me with random questions, but I was hoping there may be some specific questions that you guys could answer.

Has anybody here successfully repaired one of these?

What voltages did you read on your ic KA3525A?

I suppose this is more complicated than other repairs I have done due to a PIC18F1220-I/P processor which I haven't been able to find concrete information on as well.

I have seen a mention of a protection circuit tutorial. Where do I find it?

I originally posted this under solid state which isn't where it should have been. My apologies for cross posting it here.

Perry Babin 23rd January 2013 09:55 AM

The 3525 can function with a wide range of voltages. Is your amp producing rail voltage?

If not, you may need to post the voltage on yours.

The protection circuit troubleshooting page was likely a reference to a section of the repair tutorial that I sell. It doesn't cover the PIC in this amp.

The PIC controllers are programmable so they vary in how they operate. If the owner's manual doesn't provide the information that you need, the only meaningful information you're likely to find is regarding the power and ground connections. These ICs VERY rarely fail.

Zeptoplix 24th January 2013 04:48 AM

Hi Perry, thanks for the reply.

No rail voltage. I get -12.5V on each rail


1) 0
8).08 which dropped to .03
14).37 dropped to .01

Negative rail -12.31
Positive rail -12.31
Tip 102 and Tip 107 both read 12.51

On my protection board:

LM393 only have voltage on pin 4 and it is .4
There are two PC817, I get 5.37 on pin two of the first one. The second pin 2 is 4.21
There is a TL072, voltage only on pin 4 .4V

I also have the voltages for the pic processor,.

Perry Babin 24th January 2013 05:57 AM

The 3525 appears to be defective. The 5v output has only 0.34v on it. Either something is pulling it down or the 5v reg in the IC has failed.

Zeptoplix 24th January 2013 01:33 PM

Thank you for the advice.

I went ahead and replace the IC.

I have the following voltages.

6) 0
7) .04
14) 0
15) 12.42
16) .42

Which pin should have 5.1V on it? I am not sure what happened, but when I originally tested last week I thought I recalled having 5.1V on one of the pins.

Perry Babin 24th January 2013 02:39 PM

Pin 16.

Zeptoplix 24th January 2013 02:41 PM

What type of scenario would cause that pin voltage to drop?

Perry Babin 24th January 2013 02:45 PM

Anything loading it. It could be as simple as a bad capacitor connected between that pin and ground.

Zeptoplix 24th January 2013 02:54 PM

Ahh. I'll have to take a look then. I am a little confused, I'll have to look at the schematic to do some tracing. What about bad diodes or resistors, or shorts?

Zeptoplix 25th January 2013 03:52 AM

Ok, so after tracing circuits and testing components I decided I would try installing another new KA3525A.

Sure enough, it turns out that the new one I recently installed was in fact defective.

I get the following numbers now:
11)2.75 (this one was going up)
14)2.75 (this one was climbing as well)

Much different than the old one.

I started testing rail voltage.

On the positive rail I measured 15.45V testing from the transformer to the centre pin.

When trying to test the negative rail, I didn't touch anything but the contact on the transformer and the centre pin, but the amp when into a fault and overloaded the test speaker with enough power to damage it before I realized there was a problem... Good thing for fuses. This behaviour keeps repeating. I gave up trying to test the negative rail. I did see 16V initially before the fault started.

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