WTB: factory printed service manual for Denon AVR-3312Ci

[Bruce Toski]

I'm 68 years old, born in Miami Florida, Master ASE automotive technician, wannabe technician for electronics.

One of my speakers shorted out and now my receiver is in protection mode. I tried the reset, with no speakers attached, no change.
I disassembled the entire receiver cleaned everything, inspected, put it back together ... still the same. I'm getting a 3.7 volt surge on the ASODET trace which takes me back to a very small surface mount transistor on the back side of the HDMI PCB which appears to be part of the protection circuit.

Anyway I ordered this surface mount transistor and the surface mount capacitor next to it along with a $300 infrared solder desolder inspection station.

I well the PDF but, does anybody have the factory service manual in printed format, original, that they would sell me ?
I bought a service manual for the 3300 model, thinking it might be close, but that was a mistake and I have it for sale, $20, for anybody who has a 3300 model !

 

[TLS Guy]

I'm 68 years old, born in Miami Florida, Master ASE automotive technician, wannabe technician for electronics.

One of my speakers shorted out and now my receiver is in protection mode. I tried the reset, with no speakers attached, no change.
I disassembled the entire receiver cleaned everything, inspected, put it back together ... still the same. I'm getting a 3.7 volt surge on the ASODET trace which takes me back to a very small surface mount transistor on the back side of the HDMI PCB which appears to be part of the protection circuit.

Anyway I ordered this surface mount transistor and the surface mount capacitor next to it along with a $300 infrared solder desolder inspection station.

I well the PDF but, does anybody have the factory service manual in printed format, original, that they would sell me ?
I bought a service manual for the 3300 model, thinking it might be close, but that was a mistake and I have it for sale, $20, for anybody who has a 3300 model !

My hunch is that the protection circuit is fine. I think it is doing its job. A short like you describe generally takes down at least the power transistors in the amp that was exposed to the short. That creates a short circuit in one or both, usually both of the output transistors. This triggers the protection circuit to stop blowing up the power supply..

So my strong hunch is that the power transistors in that power amp need replacement and very likely the driver transistors and associated diodes.

Unless you are experienced and have good test equipment you are unlikely to repair this unit.

Service manuals are not usually issued these days and are considered proprietary. With surface mount components the chance of a successful home board repair is remote.

The other issue is that your receiver is 13 years old and therefore close to the end of its useful life. 14 years is considered a typical lifespan for a receiver. So, I am not sure the unit is worth any trouble or expense. Probably time to cut your losses and replace it.

 

[lovinthehd]

I'm 68 years old, born in Miami Florida, Master ASE automotive technician, wannabe technician for electronics.

One of my speakers shorted out and now my receiver is in protection mode. I tried the reset, with no speakers attached, no change.
I disassembled the entire receiver cleaned everything, inspected, put it back together ... still the same. I'm getting a 3.7 volt surge on the ASODET trace which takes me back to a very small surface mount transistor on the back side of the HDMI PCB which appears to be part of the protection circuit.

Anyway I ordered this surface mount transistor and the surface mount capacitor next to it along with a $300 infrared solder desolder inspection station.

I well the PDF but, does anybody have the factory service manual in printed format, original, that they would sell me ?
I bought a service manual for the 3300 model, thinking it might be close, but that was a mistake and I have it for sale, $20, for anybody who has a 3300 model !

Why not just print out the pdf?

 

[TLS Guy]

Why not just print out the pdf?

The pdf. he has is for the wrong receiver, so there is no point in printing it.

 

[lovinthehd]

The pdf. he has is for the wrong receiver, so there is no point in printing it.

He mentioned them separately and he's offering the 3300's for sale....but what exactly "I well the PDF but" means I'm not sure of otoh.

 

[lovinthehd]

I see you've quoted my reply but don't see anything from you....

 

[Bruce Toski]

Gents, I meant to say that I have the proper PDF now, but I am not able to go back in fix my textual error for some reason. I thought I stated the reason that I want a printed copy. The factory publications have nice size, 16 inch by 22 in, fold out schematics. Even if I go to the time and expense to drive to Kinko's to print those pages out properly, I doubt they will still be as nice of the factory publication. Initial tests with the Darlington output transistors, indicate that they are good but I have ordered another transistor tester to double check. The attached picture is of the surface mount transistor which is in the ASODET circuit. It is testing bad in circuit and it looks like it got hot, I don't know what is that red stuff ?

 

[Bruce Toski]

My hunch is that the protection circuit is fine. I think it is doing its job. A short like you describe generally takes down at least the power transistors in the amp that was exposed to the short. That creates a short circuit in one or both, usually both of the output transistors. This triggers the protection circuit to stop blowing up the power supply..

So my strong hunch is that the power transistors in that power amp need replacement and very likely the driver transistors and associated diodes.

Unless you are experienced and have good test equipment you are unlikely to repair this unit.

Service manuals are not usually issued these days and are considered proprietary. With surface mount components the chance of a successful home board repair is remote.

The other issue is that your receiver is 13 years old and therefore close to the end of its useful life. 14 years is considered a typical lifespan for a receiver. So, I am not sure the unit is worth any trouble or expense. Probably time to cut your losses and replace it.

I have already procured another Denon receiver and even though it's masochistic and financially ridiculous to repair this unit, even though it was $1,100 when new, I like challenges and I want to learn.

 

[lovinthehd]

Good luck on finding a printed manual with the fold outs and all but you may end up at Kinkos....

 

[TLS Guy]

Gents, I meant to say that I have the proper PDF now, but I am not able to go back in fix my textual error for some reason. I thought I stated the reason that I want a printed copy. The factory publications have nice size, 16 inch by 22 in, fold out schematics. Even if I go to the time and expense to drive to Kinko's to print those pages out properly, I doubt they will still be as nice of the factory publication. Initial tests with the Darlington output transistors, indicate that they are good but I have ordered another transistor tester to double check. The attached picture is of the surface mount transistor which is in the ASODET circuit. It is testing bad in circuit and it looks like it got hot, I don't know what is that red stuff ?

Well that component is certainly blown and given up its vital juices. But the problem with these sort of chases is that what you see is generally effect rather than cause.

I have no idea what the ASODET circuit is.

All I know if that I only service good vintage gear with through board soldering. I personally would not go near a unit like that to try and service it. Even in the service centers repair is by board replacement and when boards are all gone, which is usually too soon, then the units are a recycle job.

If that unit went into protection after a speaker short, I would be truly shocked if the output stage of that power amp is OK. To go into protection there had to be a big over current event, and that most likely occurred in the output stage of the shorted amp. It is that old dictum, "common things commonly happen, rare things seldom".

 

[Bruce Toski]

I have no idea what the ASODET circuit is.

*** In the Denon AVR-3312Ci, ASO stands for **Area of Safe Operation**, referring to the protection circuit that monitors output transistors to prevent damage from overcurrent or excessive power dissipation.

All I know if that I only service good vintage gear with through board soldering. I personally would not go near a unit like that to try and service it. Even in the service centers repair is by board replacement and when boards are all gone, which is usually too soon, then the units are a recycle job.

*** I too have avoided trying to repair anything surface mount, until today. I ordered a 1,250 W BGA rework station, which I am hoping will allow me to start doing the surface mount repairs, successfully, we shall see.

If that unit went into protection after a speaker short, I would be truly shocked if the output stage of that power amp is OK. To go into protection there had to be a big over current event, and that most likely occurred in the output stage of the shorted amp. It is that old dictum, "common things commonly happen, rare things seldom".

*** At this point I am not smart enough, I don't understand the protection circuitry enough, to respond. At 68 years old I'm here to learn. I can fix practically any car, and I get aggravated when I can't fix an electronic device because PCBs are not available and or I am not able to do surface mount repairs.

I have a lot to learn, so this will probably take some time, I will keep everyone posted so, hopefully you can learn something from all my efforts and trouble.

I am working on a diagram for this protection circuit, with annotation. As soon as I am done with it I will post it.

 

[TLS Guy]

Protection circuits are activated when there is a dangerous excess current event, likely to cause further damage. If the problem is corrected, then the protection circuit will deactivate. If as in your case there appears to be damage in the protection circuitry, it would indicate that it was a very severe event most likely.

My hunch is that there is extensive damage in that receiver.

 

[Bruce Toski]

Well of course I hope you're wrong, I was running three fans on top of this receiver it never even got warm, but it did have to deal with a speaker that I drove too hard and it shorted out to one ohm. I did take everything apart and saw no damage to any component, no sign of overheating. Output transistors seems to be okay, I will be rechecking of course. I'm using a Denon avr-4306 which I just found for $100.00 .... So there is no big hurry and I will be taking my time, try to do this properly, will try to be thorough, I have a lot to learn and I will keep everything up to date and hopefully everyone can learn a little bit from my travails. I want to post a schematic but I am not quite ready to do so yet.

 

[highfigh]

Gents, I meant to say that I have the proper PDF now, but I am not able to go back in fix my textual error for some reason. I thought I stated the reason that I want a printed copy. The factory publications have nice size, 16 inch by 22 in, fold out schematics. Even if I go to the time and expense to drive to Kinko's to print those pages out properly, I doubt they will still be as nice of the factory publication. Initial tests with the Darlington output transistors, indicate that they are good but I have ordered another transistor tester to double check. The attached picture is of the surface mount transistor which is in the ASODET circuit. It is testing bad in circuit and it looks like it got hot, I don't know what is that red stuff ?

Most manufacturers stopped providing paper manuals and sales info decades ago- if you use a TV that's larger than your monitor, it will be easy to read and see.

 

[TLS Guy]

Well of course I hope you're wrong, I was running three fans on top of this receiver it never even got warm, but it did have to deal with a speaker that I drove too hard and it shorted out to one ohm. I did take everything apart and saw no damage to any component, no sign of overheating. Output transistors seems to be okay, I will be rechecking of course. I'm using a Denon avr-4306 which I just found for $100.00 .... So there is no big hurry and I will be taking my time, try to do this properly, will try to be thorough, I have a lot to learn and I will keep everything up to date and hopefully everyone can learn a little bit from my travails. I want to post a schematic but I am not quite ready to do so yet.

Do you have a Variac? When you first start it, you need to bring the voltage up gradually, so if there is a problem you don't do more damage.

It would be a good idea to see if you can buy another of those receivers on eBay going for parts or repair. I would advise you strongly to replace the amp board that was shorted out. I have been down this road before when everything says the solid state devices are OK, especially the power transistors, and they are not, and you go straight back to square one, or worse.