Nikko NR 1219 Repair! Loss of Right Channel, both channels work with Mono

Ponchobrown

New Member
Hey guys I was hoping to get some help with a repair job. I just bought this receiver a month ago so I'm pretty bummed to be having issues already. As the title reads it is a NIkko NR 1219 and slowly over a day or two the right channel would go very quiet and be very distorted, Now it is constantly like this. If i turn the balance all the way right and turn up the volume you can make out the music but with considerable distortion and only quietly. I switched the speaker cables, switched the phono cables and the right channel continues like this for A and B channels. When I run it in tuner with mono selected then both channels work.

I opened it up to see if any fuses or anything jumped out and found a group of VERY hot resistors and "zener diodes".




In the last picture you should be able to see the discoloration on the board around this group. It looks clearly slightly burnt, not quite black. Could this be the cause of a single channel going out? Are there other more likely culprits?

Here is a link to the section of the schematic if that is helpful. The type came out to small to see when it is uploaded though AK.

http://imgur.com/OX7WR9f

http://imgur.com/bGu1Q51

In this picture the hot components are ZD831 ZD832 R834 and R835 on the right side.

Does anyone have any clue as to what direction I should go with this? Is it trash? Seems like easy enough components to solder which i am pretty comfortable doing but not sure if this is actually the root cause of this issue.

The full manual can be found here

http://www.hifiengine.com/manual_library/nikko/nr-1219.shtml
 
Dirty switches and/or pots, or possibly a bad solder connection, would be my guess. If both output channels work OK when in Mono, then it seems to me that the problem lies in the signal path of the right input. That is a weird looking schematic, but another guess is that the components you pointed out are part of a regulator and that running hot would be normal. As those two zeners are mounted up high, and the resistors are large, I think the designers knew that significant heat would be dissipated from those components.

Wait for others to chime in. Your amp is definitely not trash. This type of issue can be resolved.

http://www.audiokarma.org/forums/in...diots-guide-to-using-deoxit-revisited.207005/
 
I have ordered some Deoxit. It did seem to arise when my buddy started pushing the A and B channel button. Sorry i guess thats not really the schematic just an arrangement drawing. I can post pictures of the schematics however when you do mention it, it would make sense that they would mount those diodes and resistors so high. I guess there is a chance that the heat was a bit of a red herring.

Thanks for the reply, Ill post updates after cleaning here.
 
it's basically a full cap job and some transistors.. even that might not get you out of the woods so to speak. when I see those grey caps.. you need to check more than a bad resistor or diode.

as old as I am young on this forum.. the stuff is aging probably faster than I am.
 
IMHO, the post above is confusing the situation. Suggestion to do a full recap PLUS "some transistors" would likely not resolve the specific issue, and could potentially introduce more issues.

Dirty or corroded contact areas inside switches and/or pots is the most common cause of issues in older amps/receivers. Better to solve the cut-out issue before digging into a mass replacement of (most likely) still functioning parts.

After the cutout issue is resolved, and if your soldering skills are up to it, it would be beneficial to do some recapping. In particular, those caps near the hot diodes and resistors that you pointed out would be a prime area to receive attention. Again, I am fairly certain those parts are not causing the issue, nor could they cause a channel specific issue as they are part of a voltage regulator, i.e. not carrying signal. But the caps in that area have been exposed to a lot of heat over a period of time. And the original caps were (likely) rated at 85°C. On one of them it can be seen that the outer sleeve has shrunk (a visual sign of heat exposure). Modern 105°C caps are readily available and often used in recap projects. Panasonic FC would be a great choice to replace the caps on that board, and those should be available at both Mouser and Digikey (both highly regarded parts suppliers). And if you do work on that board, it would also be wise to carefully check all solder joints, in particular those of the hot running components.

But first things first. Deoxit is your friend. The instructions in that thread are pretty comprehensive. This type of work can be tedious, and is not as sexy as "a full recap job".

If you are able to make the channel distortion appear by operating switches or pots, then you will know where to concentrate your efforts. Some switches can be quite difficult to access due to their placement within the receiver. And some have little if any access openings in their body to allow insertion of the little red Deoxit tube. Sometimes switches, speaker selection switches in particular, can be very open and accessible. Every situation is different, and your receiver is not one which is known well here. The goal is to get the Deoxit inside and then work it around thoroughly (operating the switch repeatedly), while also minimizing overspray. You don't want the stuff laying on your PCB. Clean-up can be done with Isopropyl alcohol and Q-Tips or paper towels. I use bits of paper towel gently stuffed into areas adjacent to target areas to catch overspray.

Post with any further questions or additional pics. Good luck.
 
Last edited:
bad coupling cap or more likely a transistor gone bad .. might even be a bad solder joint . check solder joints for cracks first or you might be chasing around if it is that ..
start off easy and free and less problem causing ..
 
Thanks Roger! That post is excellent and thanks for spending the time to help me out. Deoxit is definitely first on the checklist, figured I would post as much info I could so I don't head down the wrong path.
 
Dirty switches and/or pots, or possibly a bad solder connection, would be my guess. If both output channels work OK when in Mono, then it seems to me that the problem lies in the signal path of the right input. That is a weird looking schematic, but another guess is that the components you pointed out are part of a regulator and that running hot would be normal. As those two zeners are mounted up high, and the resistors are large, I think the designers knew that significant heat would be dissipated from those components.

Wait for others to chime in. Your amp is definitely not trash. This type of issue can be resolved.

http://www.audiokarma.org/forums/in...diots-guide-to-using-deoxit-revisited.207005/

Ditto on this one, dirty switch or pot imo.
 
I have looked into this receiver a bit and now know that it is substantial in size and complexity. Which means working on it would be a challenge for anyone with no experience in this area. Just getting proper access to switches/pots may (or may not be) difficult. Ponchobrown, I didn't notice any clues in your posts that would indicate your level of experience.

Some additional trouble shooting steps could possibly help to isolate the source of the cutting-out issue, and allow efforts to be applied accordingly, possibly minimizing extra work.

When you said that both channels work when in Mono, it made me think that both ampifier channels are good and the problem would be in sections priior to the amps. But later you said that you had noticed the cut-out when the speaker selector buttons were pushed, and these should be after the amplifier section. Some additional testing to clarify the behaviors of the issue might be beneficial:
---when in mono, do both channels ALWAYS work regardless of the source (tuner, aux, tape-in, etc)?
---when not in mono, does the right channel issue behave the same on both speaker A and speaker B settings?

I noticed that the NR-1219 has pre-out/main-in jacks on the back:
---do you have either a separate amp or pre-amp (or another amp that has pre-out/main-in jacks), known to be working, that could be used for testing the pre and main sections of the NR-1219?
---are the pre-in and main-out sections currently connected with bare metal jumpers, or with short RCA cables?



This thread may be of interest (not to conclude that your issue is the same as described there)
http://audiokarma.org/forums/index.php?threads/nikko-nr-1219-problem.208502/

Others:
http://audiokarma.org/forums/index.php?threads/help-needed-with-nikko-nr-1219.555115/
http://audiokarma.org/forums/index.php?threads/any-love-for-a-nikko-nr-1219.674886/
 
Last edited:
Ponchobrown, did you fix it? I have the same "black burned part" on the PCB, in mine the two resistors has been replaced by earlier owner, but still this sample had some hum when I got it. Was fixed by "touching" those resistors and is now stable, but for how long? Those two resitors get really hot. It will be of great value if someone competent could take a look at schematics and guestimate what is the cause. Could help many NR-1219 owners. Thanks!

Hey guys I was hoping to get some help with a repair job. I just bought this receiver a month ago so I'm pretty bummed to be having issues already. As the title reads it is a NIkko NR 1219 and slowly over a day or two the right channel would go very quiet and be very distorted, Now it is constantly like this. If i turn the balance all the way right and turn up the volume you can make out the music but with considerable distortion and only quietly. I switched the speaker cables, switched the phono cables and the right channel continues like this for A and B channels. When I run it in tuner with mono selected then both channels work.

I opened it up to see if any fuses or anything jumped out and found a group of VERY hot resistors and "zener diodes".




In the last picture you should be able to see the discoloration on the board around this group. It looks clearly slightly burnt, not quite black. Could this be the cause of a single channel going out? Are there other more likely culprits?

Here is a link to the section of the schematic if that is helpful. The type came out to small to see when it is uploaded though AK.

http://imgur.com/OX7WR9f

http://imgur.com/bGu1Q51

In this picture the hot components are ZD831 ZD832 R834 and R835 on the right side.

Does anyone have any clue as to what direction I should go with this? Is it trash? Seems like easy enough components to solder which i am pretty comfortable doing but not sure if this is actually the root cause of this issue.

The full manual can be found here

http://www.hifiengine.com/manual_library/nikko/nr-1219.shtml
 
bad solder joint
Yes, you are right on that suspicion, but this "heat problem" at this particular part of the power supply PCB recurring on several samples of this unit must have a CAUSE, but what? What you and I have been commenting on, is most likely the EFFECT, i.e. the heat slowly corrodes the solder joint. This is why I hope someone competent will take a look at the schematic and make assumptions as to the CAUSE of the heat on those resistors, and suggest corrective measures. It is available on the above link given by Ponchobrown. Thus, question remains.
 
IMHO the cause is age - the power rating of the resistors is not being exceeded. They are 2 watt because they are dropping voltage, and that ends up generating heat. You are looking at 40 plus years of heating - it gets discolored. Other receivers of the same age have the same problems - some are worse (Pioneer 780 voltage regulators are notorious for heat damage. Some model Kenwoods people mount the regulator transistors on the frame or heatsink because of heat damage under the transistor So - 40 years of heat and the solder connections start becoming iffy. And the higher powered the receiver, the more likely it is to be a problem. Resolder. ( IMO this receiver is one of the best sounding units of that late 70's era.)

One helpful action would be to raise the resistors off the board further - some manufacturers even use ceramic stand offs.
 
IMHO the cause is age - the power rating of the resistors is not being exceeded. They are 2 watt because they are dropping voltage, and that ends up generating heat. You are looking at 40 plus years of heating - it gets discolored. Other receivers of the same age have the same problems - some are worse (Pioneer 780 voltage regulators are notorious for heat damage. Some model Kenwoods people mount the regulator transistors on the frame or heatsink because of heat damage under the transistor So - 40 years of heat and the solder connections start becoming iffy. And the higher powered the receiver, the more likely it is to be a problem. Resolder. ( IMO this receiver is one of the best sounding units of that late 70's era.)

One helpful action would be to raise the resistors off the board further - some manufacturers even use ceramic stand offs.

Thanks for the tips. Perhaps some cooling mechanism could be made.

I have two of these prodigy wonderful receivers with the awesome (and timeless) aesthetics and the excellent sound. As the only country in the world, Norway has done the blunder of replacing FM with DAB, i.e. closing FM, now showing up as the blunder of the century, people do not want DAB and refuse to replace. Groups on Facebook and an increasing number of politicians wants the whole decision reverted, etc. IOW, I use these receivers mostly for sound quality, one in each floor

Only one of these has the problem, and in this unit those voltage droppers have been replaced, but still hot as hell. In the other unit, the original resistors are there, and it does not get that hot. For example, the one with the problem has a "burnt" pcb board, while the other has a pcb board that looks completely unharmed. This is why I wonder if the CAUSE is something else, and then the warm resistors are more of an EFFECT of something out of balance. We'll see, but I doubt I will be the one detecting the failure. More into loudspeakers and audio data programming, not so sharp in plain old electronics
 
Back
Top Bottom