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Discussion Starter · #1 · (Edited)
I have a 2008 XC70 than was the unfortunate victim of clogged sunroof drains.... One day about a month ago, I drove off to get groceries and heard a strange sloshing sound from the passenger footwell....

Looking down, there was 3 inches of water ABOVE the carpet..... Needless to say, that cut my grocery trip short and I vacuumed out at least 5 gallons of water and then proceeded to remove the interior so it could dry out. After removing at least another 5 gallons of water, the passenger seat, front carpet and the audio amp, plus propping up the rear carpet, I let the car dry for a week.

The audio amp, however, was another story. It had obviously been underwater and, because it is always powered on, was live during that time. Since I have a full electronics lab, I really was not all that concerned as I can theoretically fix any piece of electronics..... So I took said amp apart and thoroughly dried it out, desiccant, heat, etc. After looking at it under a microscope, it seemed fine, there was zero obvious damage and virtually no corrosion.

So I put it back together and, it seemed to work fine at first test. But, as it warmed up, the volume would fade down to zero - only to be back a FULL volume once it had cooled down...... Fun. After carefully looking at the various identifiers on the label and at various eBay auctions for used parts (the specific XC70 part is virtually unobtainium used, esp. because this is the 'luxury' DynAudio system...), it was clear that Volvo uses the same internals with different cases. So I ordered an amp (from a V40) with what seemed to be similar internals figuring I could just swap the cases....

But Volvo, in it's infinite wisdom, decided that audio amps need to be specifically 'coded' to each car, making straight swapping impossible without downloading 'software' to the new/used unit. Aaaaargh! Why do manufacturers do this? Esp. for an amp.... Anyway - I had a solution as a friend of mine owns a high-end repair shop with the correct tools to deal with this, but there was no guarantee that unit from another car would work.

i was pretty sure I could repair the broken unit, but powering it up on the bench proved to be a bitch as it powers on from a CANBUS signal. I really didn't want to rig up my logic analyzer in the car to decode the CANBUS signal just to fix an amp, seemed like a whole lot of hassle for what should be a simple fix.... Likely one of the regulators on a power rail is bad, would be easy to see on a thermal camera IF you could power it up.

I stripped both amps down and looked over everything again. Then (after over a month - I'm not the quickest sometimes), it occurred to me that the failure was on the analog side as the volume faded smoothly - a digital failure is typically binary, on or off. Looking at the boards from the V40 premium amp, it was clear that there was only one difference, an analog-to-digital converter on the digital board and some associated circuitry on the analog board. Looking at both, this is likely for a hands-free bluetooth option my car doesn't have (or maybe the optional USB), so it was not going to do anything, which was fine.

I swapped the V40 analog board into the XC70 case with the XC70 digital board and reinstalled the whole thing in the car. I figured I had nothing to loose, worst case I buy a new amp for $500-ish and have the dealer 'install' it (e.g. software update) for $165/hr....

But, hey, my fix worked and everything seems to be back to normal.

So there you have it, that's how you fix your amp after it's been underwater and you don't want to pay $1000 for what should be just a simple swap or fix......

Hopefully this helps someone in a similar situation. Yes, the sunroof drains have been fixed - another pain in the ass Volvo moment.

Edit: speling
 

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I have a 2008 XC70 than was the unfortunate victim of clogged sunroof drains.... One day about a month ago, I drove off to get groceries and heard a strange sloshing sound from the passenger footwell....

Looking down, there was 3 inches of water ABOVE the carpet..... Needless to say, that cut my grocery trip short and I vacuumed out at least 5 gallons of water and then proceeded to remove the interior so it could dry out. After removing at least another 5 gallons of water, the passenger seat, front carpet and the audio amp, plus propping up the rear carpet, I let the car dry for a week.

The audio amp, however, was another story. It had obviously been underwater and, because it is always powered on, was live during that time. Since I have a full electronics lab, I really was not all that concerned as I can theoretically fix any piece of electronics..... So I took said amp apart and thoroughly dried it out, desiccant, heat, etc. After looking at it under a microscope, it seemed fine, there was zero obvious damage and virtually no corrosion.

So I put it back together and, it seemed to work fine at first test. But, as it warmed up, the volume would fade down to zero - only to be back a FULL volume once it had cooled down...... Fun. After carefully looking at the various identifiers on the label and at various eBay auctions for used parts (the specific XC70 part is virtually unobtainium used, esp. because this is the 'luxury' DynAudio system...), it was clear that Volvo uses the same internals with different cases. So I ordered an amp (from a V40) with what seemed to be similar internals figuring I could just swap the cases....

But Volvo, in it's infinite wisdom, decided that audio amps need to be specifically 'coded' to each car, making straight swapping impossible without downloading 'software' to the new/used unit. Aaaaargh! Why do manufacturers do this? Esp. for an amp.... Anyway - I had a solution as a friend of mine owns a high-end repair shop with the correct tools to deal with this, but there was no guarantee that unit from another car would work.

i was pretty sure I could repair the broken unit, but powering it up on the bench proved to be a bitch as it powers on from a CANBUS signal. I really didn't want to rig up my logic analyzer in the car to decode the CANBUS signal just to fix an amp, seemed like a whole lot of hassle for what should be a simple fix.... Likely one of the regulators on a power rail is bad, would be easy to see on a thermal camera IF you could power it up.

I stripped both amps down and looked over everything again. Then (after over a month - I'm not the quickest sometimes), it occurred to me that the failure was on the analog side as the volume faded smoothly - a digital failure is typically binary, on or off. Looking at the boards from the V40 premium amp, it was clear that there was only one difference, an analog-to-digital converter on the digital board and some associated circuitry on the analog board. Looking at both, this is likely for a hands-free bluetooth option my car doesn't have (or maybe the optional USB), so it was not going to do anything, which was fine.

I swapped the V40 analog board into the XC70 case with the XC70 digital board and reinstalled the whole thing in the car. I figured I had nothing to loose, worst case I buy a new amp for $500-ish and have the dealer 'install' it (e.g. software update) for $165/hr....

But, hey, my fix worked and everything seems to be back to normal.

So there you have it, that's how you fix your amp after it's been underwater and you don't want to pay $1000 for what should be just a simple swap or fix......

Hopefully this helps someone in a similar situation. Yes, the sunroof drains have been fixed - another pain in the ass Volvo moment.

Edit: speling
Damn, that's impressive! Nicely done.

Sent from my iPhone using Tapatalk
 

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Id of swapped in an aftermarket double din and amp for less then $500 lol.

But nice job!
 

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FYI the whole amp incompatibility thing varies because if the manufacture is setting a sound stage the space to work each car model is different. V40 is probably very different in size and number of speakers.

I'm no expert on the subject, but it's not so crazy an idea. Lots of the electronics of these cars are not coded to the car by vin, but are coded by options.

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