Denon AVR2307 Shuts Down with Red Blinking Power button. Can this one be repaired?

I'm not really a fan of a lot of these modern receivers just because they're extremely difficult to work on and hard to do any testing because of the way that they're constructed you've got to take the whole thing apart do anything to them that includes removing circuit boards and this one there's no different let's take a look this is a dead end APR 20 2014 2 and see if we're getting any standby voltages I tell you I was just starting to contemplate taking this whole thing apart I started to unhook wires I noticed this wire here it's going all the way up to the front looked initially like it went into the transformer but it doesn't it actually goes up to this little circuit board here and I'm looking on the front of the circuit board and lo and behold it goes to a switch and it's not marked anything just says on/off and this one says on standby and it's a master power switch oh ok let's try it on and see if we get anything now more than we did before I've got a standby light lighting up red good sign and I have lights so we'll see if this thing and it shuts off so I turned to get it on it would light up AV receiver and then it shuts off with a flashing standby light which is indicating the it's gone into shut down mode that something is being detected that is there's a failed component well there might be an output transistor now this unit here it's gonna output transistors along the top here it also has output transistors down below and the only way to access them is to take the entire unit apart of course while it's in that disassembled state there's no way to connect it to test it so we got to take it apart check for bad transistors replace anything that may be bad and then put it back together before we can even test it well let's see what the problem is you see what I mean yeah they've got this little hatch here but what good is that I mean really you can't even get at the output transistors with this whatever this is for the board I need to get at is underneath here and this does not come off this base doesn't come off it's attached to the board so the only way to take the base off is to take the face off take the back off it and take out all the screws that hold on the board and then I can lift the base off but of course doing that I'm now going to lose all of my we'll have to take this board out here this other there's another board down here it's separate so I gotta take this board up but in order to get at that I get it to remove that board that's everything over to as far as the heatsink on the leaf yeah that's everything over to here that has to come out to get at that so that's it this is a huge job take this out because all this has to come off in order to lift this out so as I take out the 10,000 screws will hold this thing together you gotta take out all these screws to the back panel off what else is holding this on there's a couple more screws I'm sure I missed some yep more screws you know this is definitely defined never be serviced like most of the modern stuff that we find today the manufacturers don't want anybody servicing them and they make them so incredibly incredibly complex as far as just taking these things down apart and do a minor repair you know you're going to spend an hour taking out screws and putting everything back together just to do a very minor repair you can see now I can take out these plugs lift these other boards out unplug now I can lift these ones out of the way unplug these unplug I still have to get this board out of the way but just just to get to this point where I can lift this board oh I have to take the whole back off and take out the input video ports of video audio parts I have to take all these out just so that I can get to the point where I can lift this board up they probably wonder what's under this plate here right absolutely nothing now are you beginning now are you beginning to understand how much of a bad design this thing is this is then I can pick it up on the edge I don't know what this crud is here looks like there's some crud between some of the pins here well they got some leakage in here between oh look at this look at this stuff I don't know whether this is the fault or not transistors are not shorted but it looks like there's some if you look here it looks like there's something like forming but like almost like corrosion between these pins it's between all these transistors it looks like there's like there's been moisture or something I'm wondering whether we're getting excessive leakage and this thing's going into shutdown I was gonna clean this crap off because the transistors are not shorted but this thing's going into a shutdown mode I'm just wondering if it's just dirt related because it's all this crap in here between all these between all the pins on these transistors hmm I've never seen that but it's right above where the the vents are so if you've got Heat if you've got moisture in the air like I'm thinking maybe someone had a humidifier or something and there was moisture or steam in the air and s as the unit was running in its dry heat through the heatsink here you're drawing heat up here and if there was moisture in the air he couldn't think I mean this just looks like that's it so like on film it's on here just gonna clean this off put the board back in and see if it's still loose in the shutdown that's weird we're gonna weird problems on the same I'm just cleaning this off with isopropyl alcohol one thing I've noticed on here on inspection is these regulators look like they are not good connection so I want to resolder these regulators and check it out see whether that makes any changes to the way that this thing is operating it just the way that it's shutting off like this almost sounds like a power problem just the the symptom of what it's doing sure sounds like a like a power supply problem and we all know how well regulators have been result or connections of being on parts to get hot such as regulators in the past so just gonna redo these connections here check some of these fusible resistors as well that feed into these regulators this ones fed to diodes here and there's a resistor across here and there's another one across here I'm just going to measure these here let's see what they see if they're open - Kay it gets a little high there's the other one over here it is that's one and the other ones off of here - Kay take that circle lower than that because I believe these are these are fusible resistors yeah those things hurt Ashok a waste of time trust it in true [Music] Cheers pulling out that's one the other one was was this one here okay that's just measurements because I think these are burned that looks like that's burned 2.8 K I think that's a little high 3 point 2 K red red silver there's a red red or orange it's like they're like point to twos now those were sisters definitely look like they're burned why they're wrong does a good question I don't have the exact size but these ones should be good enough for this Oh too low wonder why things weren't melting I see it when iron get bumped yeah we sure got bumped down to 650 I'm gonna explain why things just seem to be melting as well as it should redo those regulators now that my iron is at the proper temperature wondering why things just seemed to be taking a little longer to heat up I guess my much better I check the other fusible resistors to these other regulators as well is to them we're open okay the only thing I've found that there's a little bit out of order on this still shutting down by the way is this regulator here is a positive 15 volt regulator and if we notice when I turn on the power it's going up to positive 19 almost like almost 20 volts and then they'll shut down that's a 15 volt regulator this is a negative 15 volt regulator this is a 5 volt regulator the negative 15 is performing as it's supposed to they can get in here with my probe you can flip the power on minus 15 so it's working a positive 15 is going high now whether that's shutting the receiver down I don't know could be this is a 5 volt regulator this one's working fine I don't know why those resistors were open but they're in the 5 volt supply I'm trying to angle the speakers you guys can read it okay so this should be the the minus 15 volt supply which it is the next one over should be the plus 15 volt supply as you can see the plus 15 supply is going or is it here I throw away that's ground this should be the plus 15 supplied you can see it's going to plus 20 so the regulator itself here it's probably shot the only reason it's going to that high voltage is either a there's no load or B the regulator shop and I'm thinking what's happening on this is that the unit is going into our over voltage shut down because the regulator is not functional so I'm not to get a new 7815 to try on this thing as I don't have what I go oh I could probably just disconnect the 15 volt source down here and supply it with an external 15 volts and that would certainly tell me whether the receiver is going in to shut down due to over voltage that might be an idea because there's a strap down here they can cut and that would allow me to supply an external 15 volts without having to cold by a regulator the problem I've got is that of course the only day of the week that I can get in to the supplier is is on a Friday or Saturday so today's Monday the same be sitting here all week if I'm if I don't try to cut into that supply and supply with an external 15 volts so let's let's try that let's just cut this and see that way if I can set it to 15 volts in the amp turns on then we know that the problem is that it's an over-voltage you see in wine over voltage would cause a problem like this is that the positive and negative 15 volts are going to supply an op amp and if your voltage is a difference like that then it's going to affect the linearity of the output signal because of course the output signal is based on a positive and negative supply of the same voltage so that could certainly be why it is shutting down is that the CPU is detecting that the voltage is unbalanced and it's shutting it down that's kind of what I think is happening anyway I'm not a hunt percent sure but I think that that that's probably why it's going into shutdown before the speaker really kicks in is because it's detecting that there's a voltage imbalance another reason would be if we had an output that was shorted but I went through and checked all the outputs and none of them or shorted I've now attached it wire that I can feed with plus 15 volts will feed that in from my external power supply so I'll set that for plus 15 and we'll connect it so take my supply down to 15 point 115 volt 0 15 15 point 0 no I'll let let the current down to you know a couple hundred milliamps if you ain't out there you go I'll let it down to I think the regulator would handle about 3 amps so but ground one side here and the other side is going to get ready to power this thing up and we will feed it with 15 volts so here's the meter so if I test the voltage here on the meter we'll see that I've got 15 volts ready to supply to this wire here as they turn on the power I will connect 15 volts and see whether the unit still shuts down I got 15 volts to it now and it doesn't shut down it's not and there's the power relay we have a 15 volt regulator problem let's get some sound out of this thing then I can prove it that it's the regulator and I can go and pick that 15 volt regulator up and then you guys know what goes wrong with these Denon receivers so let's hook up some speakers so that I can prove that that's the fault see then I can publish the video knowing that all I got to do is school and change that and I can do that on the weekend and then I'll have a very happy customer who have a nice receiver that he basically got for nothing I wish people would leave me Mike's receivers like this oh wait a minute I've got a few around here I just have to fix them okay we're ready to power this up so I got to do is basically connect the negative lead to the chassis at the same time as I power the power switch up and now we should have our 15 volt to get the volume turned down to nothing and turn on some speakers and I probably got a tune something on the radio here and we figure out how to do this all speakers speakers on tuning I might have to put it on Tanna on this thing I will have to put it on Tanna on this thing well you know what that is just let's just plug some solid into this thing through the auxilary input on the front will select the auxiliary I think it's that one Robin fi Montana plugged into it and that would be why it's not tuning a the end but hey here's my power supply running 15 volts [Applause] 340 milliamps was dry now to say that this was an easy one to trumple strip is an understatement it was not a very easy one to troubleshoot primarily because this is such a difficult design to work on when they when you've got to take everything apart to get the bardo to do anything I had a couple of resistors that were open here couple fusible resistors that were open why those were open or they weren't open but they were really high they went to like 2 point 2 K why they went to there I don't know but they are in that regulation circuit they're actually for the 5 volt regulator the 15 volt regulator had failed and gone to 20 volts that was causing a voltage imbalance because you've got a negative 15 volt supply here and you got a positive 15 volt supply there that was causing a voltage imbalance to the op amps and the obviously the system control the microprocessor was checking the voltages and finding that the voltage was out of spec and was shutting the unit down feeding with an external power supply allows the unit to operate proves that the rest of the receiver is okay so now I need to do is get that part and this one will be fixed so I don't need to I'm gonna finish the video off now because we know the receiver is done it gives you guys something to watch and we'll do a follow-up when I get the part because I'll be leaving this thing in pieces I'm just gonna set it aside so that I can work on some other stuff but I'll be leaving this thing in pieces until I get the part and then we'll do a follow-up video putting in the new part and putting it all together and testing it we got it fixed we know the problem all we thought of fixed we've diagnosed it we know the problem we've got it working thanks for watching we'll catch you in part 2 as soon as they get the part for it [Music]

Channel: 12voltvids

Views: 112,058

Keywords: Denon, AVR2307, Shut Down, Dead, Power, red, flashing, light, Troubleshooting

Id: IMAeQYjQBIA

Length: 30min 5sec (1805 seconds)

Published: Mon Apr 08 2019