twh

OK, I see in the Bit Ten manual that the line level input impedance is 2.2k ohm. That should not damage the CCC by drawing too much power, so I'm wondering what else could have done it.

Takechan

Thanks for checking that. I wasn't sure whether the Bit Ten could have caused the problem...

If I blow the new one I'll cry

Takechan

twh, thinking about what could have gone wrong something popped into my mind. The soldering on the input cables might not have been perfect.

Could a poor soldering job on the speaker level input cables have increased resistance and caused the HU to blow? Is there a way to check cable wiring for increased resistance due to poor soldering?

twh

Poor soldering job could be a problem. The failure mechanism isn't increased resistance, but decreased resistance. The higher the resistance of a speaker, the less power is draws. For example, 2 ohm speakers need a lot of power and 8 ohm speakers need less.

Perhaps your soldering job created a short of the speaker wires and fried the output amplifier of the CCC. Even a temporary short is a problem. But, often when this happens, it is only the one channel that gets shorted and then fried and not all of them. You can check wiring for shorts and continuity with an ohm meter. For what you are doing, you really need this tool to double check connections are what you think they should be.

Takechan

I have performed continuity checks for all but the wiring on the input speaker cables because they terminate in the trunk and they are connected to the CCC. I'll try to jump the wires in the car and measure the continuity in the trunk.

Thanks for the help/support.

Takechan

Hi, I shorted the input wires and measured the continuity and resistance in the car. All the input cables checked out with a resistance of 00.2 - 00.3.

I did the same for the speaker cables and the results were the same.

This should hopefully point in the direction that poor soldering wasn't the cause of my blown HU?

twh

You should do more checks:

(1) Check each wire individually from the one side to the other without shorting the + and - wires together. This should be 0 ohm or close to it (like your 0.2 ohm).

(2) Without shorting the + and - wires, check the resistance between the + and - wire. This resistance should be very large (M ohms).

(3) Now check each wire to ground. This resistance should be very large (M ohms).

Takechan

Hi twh,

I've done a few more checks. I measured the resistance of all the speakers, the front left has a higher impendance than the rest (6.5 Ohms). The rest are approximately 4 Ohms...

Seeing this I recall the problem I had with my Blaupunkt THA-555 amp, whenever I unlocked the car the amp would go in protection mode. If I unplugged the front speakers and reconnected them it would light up green. This would NOT work with the other inputs or rear speaker output cables, only the front. So, there may be something wrong with the speaker (FL) or the cables. I'll try to do more checks as you sugguested (e.g. wire to ground).

I'll keep going

Takechan

So, I removed the front left panel and tried to look for a short or ground issue. I didn't find anything, but after I messed around with the speaker cables and filter it measured 4 Ohm as it should...

I tried to reconnect the Audison and the amp directly but no luck. When I turn up the volume the Audison restarts and starts blinking. When the HU is connected to the amp it works at low volume, but when I turn up the volume the sound dissapears from the car. I had to disconnect the amp and reconnect the speakers directly to the HU and disconnect/reconnect the battery before sound returned :'(

Takechan

Solved!

I measured all the cables to ground (again) and found that the front left cable was shorted to ground :'( It was underneath the drivers seat it had gotten squeezed.

Everything works now and it sounds EPIC! However; the navi voice and PDC is a bit too loud, so I'll have to figure out how to lower that. Sensitivity on DSP or amp?

Thanks for all the input.