Here are a few pics of my Logic7 amp circuit board. Its from a BMW 2007 E90.
I pulled it apart because the underseat woofers were barely audible.
Is there anything obviously wrong with it? Is the green goo supposed to be there?
I am a complete noob at this. If its possible for me to fix it id like to rather than taking to a repair shop.
I pulled it apart because the underseat woofers were barely audible.
Is there anything obviously wrong with it? Is the green goo supposed to be there?
I am a complete noob at this. If its possible for me to fix it id like to rather than taking to a repair shop.
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Thanks good to know.
A local repair shop told me it cant be fixed because its digital and must be replaced. Problem is these amps are US 800 thereabouts new. So thats out of the question.
What is the correct way to test the ICs with a multimeter? Can you link me a guide or something to follow? I have read the ICs can be replaced which should hopefully fix it.
Thanks!
These are the specs i was able to find on the amp:
9 channels, 13 loudspeakers
• 1 mid-range loudspeaker, middle, 100 mm
• 2 treble loudspeakers, front 26 mm
• 2 mid-range loudspeakers, front 100 mm
• 2 bass loudspeakers, 217 mm
• 2 mid-range loudspeakers, rear door, 100 mm
• 2 mid-range loudspeakers, rear shelf, 100 mm
• 2 treble loudspeakers, rear shelf, 26 mm
Bandwidth: 30 Hz to 20.000 Hz
Max. acoustic pressure: 110 dB
Amplifier power:
2 x 70 W (4 Ω) Bass
7 x 40 W (2 Ω)
9 channels, 13 loudspeakers
• 1 mid-range loudspeaker, middle, 100 mm
• 2 treble loudspeakers, front 26 mm
• 2 mid-range loudspeakers, front 100 mm
• 2 bass loudspeakers, 217 mm
• 2 mid-range loudspeakers, rear door, 100 mm
• 2 mid-range loudspeakers, rear shelf, 100 mm
• 2 treble loudspeakers, rear shelf, 26 mm
Bandwidth: 30 Hz to 20.000 Hz
Max. acoustic pressure: 110 dB
Amplifier power:
2 x 70 W (4 Ω) Bass
7 x 40 W (2 Ω)
If the audio from the woofers was clean but low, I would expect the problem to be elsewhere. Generally when an amp fails, audio is absent or distorted.
It's difficult to test ICs like these with a multimeter except to compare the readings from one to another.
If they have the original part number on the ICs, you may be able to get replacements but many times, OEM amps like these have markings that are specific to the vehicle or amp manufacturer.
It's difficult to test ICs like these with a multimeter except to compare the readings from one to another.
If they have the original part number on the ICs, you may be able to get replacements but many times, OEM amps like these have markings that are specific to the vehicle or amp manufacturer.
On the BMW forums its a well reported problem of the amps failing to power the woofers. I have also removed the woofers and they are working perfectly when i hooked them up to my home stereo.
So I have cleaned up all the thermal paste off the ICs and the 6 large ones have no markings but the three small ones do. Two of the small ICs have the same number so im guessing they are the bass ICs - as the amp spec has two channels for bass.
I found a datasheet for the IC too. Does that help in order to test the ICs?
Or can I just buy two of them and replace?
So I have cleaned up all the thermal paste off the ICs and the 6 large ones have no markings but the three small ones do. Two of the small ICs have the same number so im guessing they are the bass ICs - as the amp spec has two channels for bass.
I found a datasheet for the IC too. Does that help in order to test the ICs?
Or can I just buy two of them and replace?
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From what I have read on the forums its either replace or send to someone to repair. There is no useful DIYs unfortunately.
Here is a link to the datasheet I found - http://www.mouser.com/ds/2/389/CD00001329-250093.pdf
Is this a FET? Does that mean it is not a IC and nothing to do with the bass?
Here is a link to the datasheet I found - http://www.mouser.com/ds/2/389/CD00001329-250093.pdf
Is this a FET? Does that mean it is not a IC and nothing to do with the bass?
My mistake. The rectifiers convert the AC out of a transformer to DC.
Just a guess but I'd say that the sub amp has a switching power supply. The FET and rectifiers could be for that supply. The rest of the ICs likely operate from 12v.
If the audio is clean but low, that's rarely a power supply problem. When the supply fails, the audio is generally lost or very distorted.
Just a guess but I'd say that the sub amp has a switching power supply. The FET and rectifiers could be for that supply. The rest of the ICs likely operate from 12v.
If the audio is clean but low, that's rarely a power supply problem. When the supply fails, the audio is generally lost or very distorted.
After a little digging I found that the 2 woofer amp chips are TDA1562Q's and the other 4 are TDA8563AQ's. All of these are 12 volt chips, however the TDA1562Q's use an internal charge pump set up to make their 70 watt rating. The 6 2200uF capacitors are the 12 volt rail bypass units and the 4 10,000uF caps are for the charge pumps. None of these appear to be defective from a cosmetic stand point, no bulging tops or leaking brownish gunk. The mosfet and rectifiers are part of a regulator circuit for the logic/digital end of the amp. If the bass channels sound clean just low volume, the dsp/preamp end of things may be suspect.
Thanks Jerluwoo thats very helpful.
There is a repair kit I have found for these amps and I have asked the seller to explain what is in the kit. If it is replacing the 2 woofer chips then i should be able to just buy 2 of the chips and solder them in.
Im not sure what it means when you say bass channels sound clean. The bass works on the mid speakers but on the underseat woofers there is hardly any sound coming through at all even at high volume. Basically inaudible unless I lift up the seat and put my ear to the speaker.
Does this mean the dsp/preamp would be the problem and not the woofer amp chips?
Repair kits: http://www.diyparadise.net/logic_7_repair_kit.html and http://www.dg-onlineshop.de/index.php?cat=KAT10&product=124
Edit: just received a response from one of the repair kit sellers. They are saying the repair kit replaces the 2 woofer amp chips.
There is a repair kit I have found for these amps and I have asked the seller to explain what is in the kit. If it is replacing the 2 woofer chips then i should be able to just buy 2 of the chips and solder them in.
Im not sure what it means when you say bass channels sound clean. The bass works on the mid speakers but on the underseat woofers there is hardly any sound coming through at all even at high volume. Basically inaudible unless I lift up the seat and put my ear to the speaker.
Does this mean the dsp/preamp would be the problem and not the woofer amp chips?
Repair kits: http://www.diyparadise.net/logic_7_repair_kit.html and http://www.dg-onlineshop.de/index.php?cat=KAT10&product=124
Edit: just received a response from one of the repair kit sellers. They are saying the repair kit replaces the 2 woofer amp chips.
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Is there a chart or diagram showing which are the TDA1562Q chips on the board? I will replace them but need to know which ones are which,. They all look exactly the same.
If you're not going to do any further troubleshooting...
* Buy ICs with the legs already bent the same as yours.
* Cut the legs from the IC at the body of the IC. Use either fine cutters or use a razor knife and repeated passes until the legs are cut free. Then heat and remove each leg individually.
* Use a good quality desoldering pump.
* Use a good soldering iron.
* When desoldering the vias, add new solder, heat the solder and desolder with the pump. It's best if you don't allow the tip of the iron to contact the pads.
* Buy ICs with the legs already bent the same as yours.
* Cut the legs from the IC at the body of the IC. Use either fine cutters or use a razor knife and repeated passes until the legs are cut free. Then heat and remove each leg individually.
* Use a good quality desoldering pump.
* Use a good soldering iron.
* When desoldering the vias, add new solder, heat the solder and desolder with the pump. It's best if you don't allow the tip of the iron to contact the pads.
I saw on another forum that a member didnt replace the woofer chips but used a secondary amp instead by wiring into the circuit.
Im thinking if this might be a better way to go. Does the woofer chip / aftermarket amp only power the underseat woofers? Would a separate woofer amp provide more power to all the speakers or just the woofers? It would cost more to go down this route but not sure if it would be worth it if its only for the underseat woofers.
Wiring diagram attached.
Im thinking if this might be a better way to go. Does the woofer chip / aftermarket amp only power the underseat woofers? Would a separate woofer amp provide more power to all the speakers or just the woofers? It would cost more to go down this route but not sure if it would be worth it if its only for the underseat woofers.
Wiring diagram attached.
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I think you need to determine if the problem is the signal level getting to the IC or the IC itself.
The wiring shown in the photo would only go to the amp that would power the under-seat woofers.
In general, the OEM speakers in a car are optimized to work with the OEM amps. If a larger amp is used, there's no guarantee that you'll get any more clean output from them.
Did the person using the external amp have enough signal level?
The wiring shown in the photo would only go to the amp that would power the under-seat woofers.
In general, the OEM speakers in a car are optimized to work with the OEM amps. If a larger amp is used, there's no guarantee that you'll get any more clean output from them.
Did the person using the external amp have enough signal level?
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