Hi all - I've been reading through all the posts of people having issues with their NAD amplifiers, but I haven't come across the specific issue I'm having and I'm a bit lost:
When turning on, the amp just goes into this loop of clicking the relay(s) every second or so, and the light is orange/red. I've opened it up, and the R401 and R402 are already replaced with a jumper as per the service bulletin. The caps look like they haven't leaked, but I only have a multimeter and I'm not sure if that's enough to measure them.
Any advice or suggestions what I can test to narrow down the issue?
Thanks in advance,
Felix
When turning on, the amp just goes into this loop of clicking the relay(s) every second or so, and the light is orange/red. I've opened it up, and the R401 and R402 are already replaced with a jumper as per the service bulletin. The caps look like they haven't leaked, but I only have a multimeter and I'm not sure if that's enough to measure them.
Any advice or suggestions what I can test to narrow down the issue?
Thanks in advance,
Felix
First step is to see which relay/s is or are clicking. There is one for the speaker output and one for the power supply. The first proper step in any faultfinding like this is to measure the voltage rails and make sure they are all correct.
hey but if you buy used one and upgrade components they really are a good design with proper parts they are great
I have a Technics amp that had the same symptoms that you have. The first thing I did was to measure the voltage at the output terminal to see if there was a dc fault output fault but there was'nt. The pcb component side was phenolic which is less rigid than fibre glass and the relay was a heavy duty one and the clicking was noticeably louder than others in my experience. I reasoned that the mechanical forces of opening and closing over the life of the amp had some effect on the pcb as this was quite flexible. To prove the theory I tried applying some gentle index finger pressure on the top of the pcb where relay legs were and the fault disappeared momentarily.
Visual inspection revealed no visible cracks in the pcb so I remade the solder joints to the copper side and that solved my problem.
Nitrogen spray likely would have showed visible cracks. Old solder joints may exhibit this when not done 100% right in the factory and age plus mechanical force do have their say in this. It is not the same phenomenon as observed in NAD/Bluesound devices where part quality usually is so so and often corners have been cut. Not ALL devices but quite many.
Sometimes design choices are made that make one wonder how devices could have endured the years they did. Excellent stuff to teach laymen what design errors/imperfections look like as they can already see them with moderate knowledge. "Can you tell me what you would have done differently if you had been the designer?"
Sometimes design choices are made that make one wonder how devices could have endured the years they did. Excellent stuff to teach laymen what design errors/imperfections look like as they can already see them with moderate knowledge. "Can you tell me what you would have done differently if you had been the designer?"
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I would add that solder joints could be made more secure by firstly gently bending or twisting the pins under the pcb if possible and then applying solder..
I routinely bend the leads of components to keep them in place for soldering, but there is another benefit. It ensures an actual metal to metal contact rather than relying on solder to do the job. The only downside is that it will be a bit more difficult to remove the soldered component should you have to. Also, it is fortunate that circuit boards have come quite a long way (if that is what the designer chooses!) and can be very reliable compared to the old brown boards that age poorly.