I have had the C390DD since mid 2014 and it has had the problem of occasionally not switching on from the beginning. Actually I thought this was a software issue, because doing a 'hard reset' using the switch on the back always solved the issue. It didn't happen very often so it was not a big issue, although a bit of a nuisance. In 2015 something went wrong in the power supply. When I switched the amp on, my circuit breaker in the house tripped and I had to send the amp for repair. The SMPS was replaced, but unfortunately it did not solve the issue of sometimes not switching on. Back then I also searched the web for more information, but did not find anything. Recently, switching on the amp became impossible. Also using the switch on the back did not help. I did a new google search which almost immediately led me here. Apparently this is a common problem with this amplifier. By the way, I also found the service doc, so if someone is interested I can upload it. Seems they drew the schematics in Altium, which is one of the better tools in my opinion.
I plan to look at this more into detail, but first I have a question, mainly to Wim Janse and Jabbejokker: Did replacing the capacitors by the types mentioned solve the issue for you?
I plan to look at this more into detail, but first I have a question, mainly to Wim Janse and Jabbejokker: Did replacing the capacitors by the types mentioned solve the issue for you?
I just attempted this repair without doing any diagnostics. My units symptom was exactly the same as the OPs. I only replaced the caps the OP mentioned, with Panasonic low ESR FM caps.
Still suffering the same symptom
Well that shouldn't be the reason for my VFD not being on - that's just the supply to the amp board?
My electronic skills are clearly very rusty - posting my own thread to solicit help in troubleshooting.
Same as Henk
Hello, I just joined diyaudio.com because of this problem with the NAD C390DD.
It looks like this thread is kind a left behind, but I want to try anyway.
I have the exact same problems as Henk described.
I just disassembled the PSU B board from my receiver, and want to order the mentioned parts.
Question: especially for Henk; did you manage to solve the problem?
What parts did you change exactly?
Thanks in advance for any reply!
Hello, I just joined diyaudio.com because of this problem with the NAD C390DD.
It looks like this thread is kind a left behind, but I want to try anyway.
I have the exact same problems as Henk described.
I just disassembled the PSU B board from my receiver, and want to order the mentioned parts.
Question: especially for Henk; did you manage to solve the problem?
What parts did you change exactly?
Thanks in advance for any reply!
Solved
To close my earlier posted problem:
As mentioned earlier I had the exact same problem as described by Henk.
After reading this thread I decided to change all capacitors mentioned, on the PSU-B PCB.
Replaced:
C204, C205, C210, C211, C212, C213 and C217
Afterwards tested the capacitors and only the big one (C212) was totally down, rest was still ok, but I chose to replace all of them because I was there anyway, and for the money you don’t have to leave it (capacitors cost me less than €10 for all seven).
Tested and found everything working correct again.
Thanks for posting to all of you!
To close my earlier posted problem:
As mentioned earlier I had the exact same problem as described by Henk.
After reading this thread I decided to change all capacitors mentioned, on the PSU-B PCB.
Replaced:
C204, C205, C210, C211, C212, C213 and C217
Afterwards tested the capacitors and only the big one (C212) was totally down, rest was still ok, but I chose to replace all of them because I was there anyway, and for the money you don’t have to leave it (capacitors cost me less than €10 for all seven).
Tested and found everything working correct again.
Thanks for posting to all of you!
Mine was repaired this week in the same way by a collegue and also works again. Also from my side thanks for posting this.
The last time I checked back here was a few months ago, early March I think. Since then there have been some new postings. Sorry for late reaction.
From Wim I already heard that replacing the capacitors which were mentioned by Ergo seemed to work initially, but ultimately didn’t. This is now confirmed by jasonnumber6. Since I have had the problem of the amp not switching on occasionally from the moment I had it (new), I figured that just changing the capacitors as mentioned earlier in this thread would not be enough. Therefore I also did some research into the start-up behavior of the used Power Integrations TOP246Y. I did find some interesting stuff, but I will come back to that later since information about it would be premature, and maybe not necessary anymore. However, since I was at it anyway, and since these capacitors are not expensive, I changed them all. The large capacitors on the secondary of the supply (C210, C211) I changed by Panasonic FP types, the other capacitors (C204, C205, C213, C217) by Panasonic NHG. The 400V capacitor at the input which was from Lelon, I replaced with a Nichicon UCY type. All the other types originally were from Jianghai. Removing those smaller caps was more difficult than removing the bigger ones. The bigger ones were easy to desolder. After this, the amplifier started up normally again.
This is the same as what JeroenAJ did, with the same result. Jeroen found that the 400V capacitor at the input, C212, was not good anymore. That may explain why Wim and jasonnumber6 did not fix the issue. So it maybe that C212 it the first capacitor to look at.
From Wim I already heard that replacing the capacitors which were mentioned by Ergo seemed to work initially, but ultimately didn’t. This is now confirmed by jasonnumber6. Since I have had the problem of the amp not switching on occasionally from the moment I had it (new), I figured that just changing the capacitors as mentioned earlier in this thread would not be enough. Therefore I also did some research into the start-up behavior of the used Power Integrations TOP246Y. I did find some interesting stuff, but I will come back to that later since information about it would be premature, and maybe not necessary anymore. However, since I was at it anyway, and since these capacitors are not expensive, I changed them all. The large capacitors on the secondary of the supply (C210, C211) I changed by Panasonic FP types, the other capacitors (C204, C205, C213, C217) by Panasonic NHG. The 400V capacitor at the input which was from Lelon, I replaced with a Nichicon UCY type. All the other types originally were from Jianghai. Removing those smaller caps was more difficult than removing the bigger ones. The bigger ones were easy to desolder. After this, the amplifier started up normally again.
This is the same as what JeroenAJ did, with the same result. Jeroen found that the 400V capacitor at the input, C212, was not good anymore. That may explain why Wim and jasonnumber6 did not fix the issue. So it maybe that C212 it the first capacitor to look at.
My 390dd amp had the same issues as original poster, a friend swapped C204, C205 which helped to revive the amp.
But after a few months the same not willing to power up problem came back. Swapping C210, C211 and C212 in addition did not help. Power level of 12.5V on J203 fluctuates between 2 and 4.5V..
Likely there is more to it this time.. given I noticed a few posts from Dutch people: any recommendations for a repair guy/center close to Amsterdam who can do the next level of investigation?
But after a few months the same not willing to power up problem came back. Swapping C210, C211 and C212 in addition did not help. Power level of 12.5V on J203 fluctuates between 2 and 4.5V..
Likely there is more to it this time.. given I noticed a few posts from Dutch people: any recommendations for a repair guy/center close to Amsterdam who can do the next level of investigation?
display freezes
Hello. I'd like to ask your advice.I also have a NAD c390DD amplifier.After about three years of use, it started to make the following problem. When I turn the amplifier on, after about 3-10 minutes, the display completely freezes. Otherwise, everything works. Volume settings, input switches, etc..... It just freezes the display. Turning off and on or disconnecting from the power suply does not help. Resetting to factory settings also did not help..The amplifier starts with the display frozen. But I observed that if I disconnected the amplifier from its power source for an extended period (in hours), the displey would function normally after takeoff, but after a while it would freeze again. Even about a year ago, I put the amplifier in a box where it rested for nearly six months. And after that, everything worked for almost three months with no problems whatsoever. But now it has all come back. Do you think that replacing the capacitors mentioned here could help with this problem? I'm a total layman within electronics. Also, please excuse my English. I love NAD c390DD, and I want him back in good shape. Thank you so much for any help. Many regards from Prague from the Czech Republic.
Hello. I'd like to ask your advice.I also have a NAD c390DD amplifier.After about three years of use, it started to make the following problem. When I turn the amplifier on, after about 3-10 minutes, the display completely freezes. Otherwise, everything works. Volume settings, input switches, etc..... It just freezes the display. Turning off and on or disconnecting from the power suply does not help. Resetting to factory settings also did not help..The amplifier starts with the display frozen. But I observed that if I disconnected the amplifier from its power source for an extended period (in hours), the displey would function normally after takeoff, but after a while it would freeze again. Even about a year ago, I put the amplifier in a box where it rested for nearly six months. And after that, everything worked for almost three months with no problems whatsoever. But now it has all come back. Do you think that replacing the capacitors mentioned here could help with this problem? I'm a total layman within electronics. Also, please excuse my English. I love NAD c390DD, and I want him back in good shape. Thank you so much for any help. Many regards from Prague from the Czech Republic.
I have the same problem. I will do some testing coming weeks. How did you resolve the problem?
Kind regards
A much delayed update from my earlier post. Sometime after that post in early 2019 I think, I went through and replaced all leaded electrolytic capacitors on all PCBs in the whole unit with Japanese brand capacitors. For the smaller capacitors I tried to get mostly long life capacitors rated for high ripple and suggested for switch mode power supplies where available.
I had not actually noticed any functional issue, just noticed bulging capacitors and thought it best to change them before the amplifier failed. At the time I had also noticed a bulging capacitor c59 on the main amp board, so I expect the failing caps on the PSU-B board increased ripple which damaged that capacitor downstream.
I just thought it was better to replace all capacitors for piece of mind as I don't know how far the issue had already spread.
I would caution that changing _all_ the capacitors might not be a great idea and is probably not needed. I am inexperienced in electronics and I found removing all the capacitors a massive pain and it took ages. Also with lots of small components on the main amp board close to the capacitors there is a lot of opportunity to do damage. Could cause more problems than it solves. If you are experienced in electronics it may not be a problem for you.
Anyway after all that the amplifier still worked.
Sometime after the rebuild, I found that I had a minor issue with powering on the amplifier with the remote. It usually does not power on first time of the day on the first press of the remote "on" button. Usually it will power on on the second press and sometimes a third is needed. This issue does not occur if using the front panel power button. Also the issue does not occur with the remote if I use a completely different remote to operate something else nearby, then use the c390dd remote to power on the amplifier - works first go then. Also after the amplifier is fully powered on - the remote works well to operate the amplifier.
It is kind of like the IR sensor or some of its supporting electronics needs a bit of IR to wake it up before it starts working properly if it has not been used in a while.
I have looked for dry or bad solder joints and have not found any obvious ones. Perhaps I used an inappropriate capacitor somewhere which has caused the problem. Or perhaps it is unrelated to the capacitor change.
The 5V standby voltage measures fine.
Understanding the schematic in the service manual is beyond my current abilities so don't know what else to look at. It might just be something I will live with as it is quite a minor issue. Not expecting any suggestions on fixes here but you are welcome to suggest if you like. This is more just a report on my experience with changing capacitors.
I had not actually noticed any functional issue, just noticed bulging capacitors and thought it best to change them before the amplifier failed. At the time I had also noticed a bulging capacitor c59 on the main amp board, so I expect the failing caps on the PSU-B board increased ripple which damaged that capacitor downstream.
I just thought it was better to replace all capacitors for piece of mind as I don't know how far the issue had already spread.
I would caution that changing _all_ the capacitors might not be a great idea and is probably not needed. I am inexperienced in electronics and I found removing all the capacitors a massive pain and it took ages. Also with lots of small components on the main amp board close to the capacitors there is a lot of opportunity to do damage. Could cause more problems than it solves. If you are experienced in electronics it may not be a problem for you.
Anyway after all that the amplifier still worked.
Sometime after the rebuild, I found that I had a minor issue with powering on the amplifier with the remote. It usually does not power on first time of the day on the first press of the remote "on" button. Usually it will power on on the second press and sometimes a third is needed. This issue does not occur if using the front panel power button. Also the issue does not occur with the remote if I use a completely different remote to operate something else nearby, then use the c390dd remote to power on the amplifier - works first go then. Also after the amplifier is fully powered on - the remote works well to operate the amplifier.
It is kind of like the IR sensor or some of its supporting electronics needs a bit of IR to wake it up before it starts working properly if it has not been used in a while.
I have looked for dry or bad solder joints and have not found any obvious ones. Perhaps I used an inappropriate capacitor somewhere which has caused the problem. Or perhaps it is unrelated to the capacitor change.
The 5V standby voltage measures fine.
Understanding the schematic in the service manual is beyond my current abilities so don't know what else to look at. It might just be something I will live with as it is quite a minor issue. Not expecting any suggestions on fixes here but you are welcome to suggest if you like. This is more just a report on my experience with changing capacitors.
If it has never had it's capacitors replaced, there is a good chance that they could be the problem. If you are comfortable taking the top case off the amplifier you could then take a look at the capacitors (the small cylinder shaped components) in the PSU-B board and see if any of them are bulging at the top. They should have flat tops so bulging indicates a problem. You call also check the capacitors elsewhere on the other boards. If they are bulging they have to be replaced anyway, even if that is not the ultimate fix for this problem. It is a good first step.
In the attached image, notice the big green capacitor and two of the smaller capacitors are bulging. They are bad.
Due to it being an intermittent issue, it might also be a problem with bad solder joints that need to be re-soldered.
There are a lot of dangerous high voltages inside so while it is ok to take a look at things to look for obvious problems like bulging capacitors, since you mention "I'm a total layman within electronics" it may be best to get an electronic repairer to do the actual repair. You could show them this thread. Up to you to decide if you can do this work yourself or not.
Attachments
Further to my last post, since it is just a display problem, I would be looking at the following:
- The above things I mentioned in relation to capacitors and bad solder joints
- Checking psu-b voltages, in particular the 5v and 12.5V voltages.
- The main_pcb (the vertical board) and the hidden front panel board that has the display attached. Checking mainly for bad solder joints.
- While power is off and unplugged, carefully unplugging and plugging back in the ribbon cable going between the main_pcb and the front panel board, in case it has a bad connection. Perhaps also the ribbon cable from the psu-b to the main_pcb.
- The above things I mentioned in relation to capacitors and bad solder joints
- Checking psu-b voltages, in particular the 5v and 12.5V voltages.
- The main_pcb (the vertical board) and the hidden front panel board that has the display attached. Checking mainly for bad solder joints.
- While power is off and unplugged, carefully unplugging and plugging back in the ribbon cable going between the main_pcb and the front panel board, in case it has a bad connection. Perhaps also the ribbon cable from the psu-b to the main_pcb.
I have swollen capacitors on the amplifier board, I had to replace them. But I put it not at 4700 uf, but at 6800. Subjectively, after replacing, there appears more bass. But perhaps I was slowly getting used to the slowly disappearing bass, since the capacitors also lost capacity not quickly.
Alright. Bringing back this thread. I bought a non-working unit with same issue. No display . the orange light turns to blue but nothing happens. I measures the point where it saif 5vdc and 12.5vdc. It measures 3.8vdc and when one nothing changes. The probe being so close, i was touching with same probe and the unit was going off. Maybe the pin touched both 5vdc and ground together. Anyway I am not too good in desoldering so will need to give it to a professional. I see atleast 3 caps with top portion but bulged out. C210 and C211, C204 and C205. Is there a way I can get the full board as replacement? Any thoughts on how to proceed. Thanks