Another way to learn from the experience is to attempt to repair it. Depending on your skills and what equipment you have access to.
In economic terms it most likely doesn't make sense, at least if you count even a very modest hourly salary, but it can be a good learning experience.
If the various DC/DC regulators and LDO's can be identified, it will be easier to estimate if they survived.
What is the state of the FET? Is it shorted or is it open. If it is shorted, the unit should probably work normally if all other regulators survived (which is unlikely). It just cannot save power when turned off.
I would start by measuring if the DCIN is shorted to ground.
If not, then I would apply 5V from a lab power supply, with a current limitation set to e.g., around 100mA.
Then measure the voltages after the various regulators. Do they pass through 5V directly? In that case they are probably destroyed.
If the FET is open some parts of the design will not be powered at all, so probably only the micro controller section is powered. The "AD" LDO is powered from DCIN via a diode, so not from the supply through the FET.
If the voltages are okay then you can try to increase the current limit. If the unit draws more than 100mA the supply voltage from the lab supply may already drop due to the 100mA limit.
Good luck with the repair. 🙂
In economic terms it most likely doesn't make sense, at least if you count even a very modest hourly salary, but it can be a good learning experience.
If the various DC/DC regulators and LDO's can be identified, it will be easier to estimate if they survived.
What is the state of the FET? Is it shorted or is it open. If it is shorted, the unit should probably work normally if all other regulators survived (which is unlikely). It just cannot save power when turned off.
I would start by measuring if the DCIN is shorted to ground.
If not, then I would apply 5V from a lab power supply, with a current limitation set to e.g., around 100mA.
Then measure the voltages after the various regulators. Do they pass through 5V directly? In that case they are probably destroyed.
If the FET is open some parts of the design will not be powered at all, so probably only the micro controller section is powered. The "AD" LDO is powered from DCIN via a diode, so not from the supply through the FET.
If the voltages are okay then you can try to increase the current limit. If the unit draws more than 100mA the supply voltage from the lab supply may already drop due to the 100mA limit.
Good luck with the repair. 🙂
Of course I meant the same except I would draw the line at replacing the MOSFET (after first removing it and shorting D and S. If there are more broken parts the other chips may either be kaput or they will be in some time which will make it both time eating and money burning still without result. Rich experience in going that extra mile 🙂 SMSL and Topping are usually not optimal for repair. PCB tracks coming loose, sometimes here unknown or unavailable chinese parts, no clear part indication etc.
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Hi jean-paul,
Yes, for many years I label adapters as to what they go with. With barrel connectors you'll find AC at various voltages and currents, DC with both polarities, many voltages and current draws. Of course they have a few close barrel connector sizes (brilliant!).
The only thing you can be sure of is a USB connector, then current draw is the question.
I do get items in for service where the wrong power supply was used. Those vary between minor repair and not repairable.
Yes, for many years I label adapters as to what they go with. With barrel connectors you'll find AC at various voltages and currents, DC with both polarities, many voltages and current draws. Of course they have a few close barrel connector sizes (brilliant!).
The only thing you can be sure of is a USB connector, then current draw is the question.
I do get items in for service where the wrong power supply was used. Those vary between minor repair and not repairable.
I'll report back on how this goes. I'm stopping at changing the MOSFET. Low hopes but fun ride.
Not having researched I a while and with black Friday coming up, any recommendations on an okay DAC under $200 CAD with a Bluetooth option?
I also have a 2 ohm subwoofer in an enclosure capable of 800WRMS. It's from the marine world when I did audio systems in boats. I don't want to waste it, it's brand new and worth $3k. Anyway of running power to it at a low cost or should I start a different thread? I do have a matching amplifier that could power it but it needs 12V @ 65 A
Not having researched I a while and with black Friday coming up, any recommendations on an okay DAC under $200 CAD with a Bluetooth option?
I also have a 2 ohm subwoofer in an enclosure capable of 800WRMS. It's from the marine world when I did audio systems in boats. I don't want to waste it, it's brand new and worth $3k. Anyway of running power to it at a low cost or should I start a different thread? I do have a matching amplifier that could power it but it needs 12V @ 65 A
Hi mrgarison,
New thread in car audio. They are 12V - right?
DACs.I ended up getting some streamers and outboard DACs to get the sound quality I wanted. The streamers are grouped so I can have the same music everywhere. Works great. The combination costs more than $200, but you could get a streamer off AMazon and add the DAC later.
I looked for a decent streamer for a while at reasonable cost. Couldn't find one. I bought an expensive Bluesound early, sounded great for a bit, ran into all kinds of issues. Now it's a paperweight. Garbage.
New thread in car audio. They are 12V - right?
DACs.I ended up getting some streamers and outboard DACs to get the sound quality I wanted. The streamers are grouped so I can have the same music everywhere. Works great. The combination costs more than $200, but you could get a streamer off AMazon and add the DAC later.
I looked for a decent streamer for a while at reasonable cost. Couldn't find one. I bought an expensive Bluesound early, sounded great for a bit, ran into all kinds of issues. Now it's a paperweight. Garbage.
Yes 5.5 x 2.1 and 5.5 x 2.5 are the least OK connectors but they're cheap. Cheap always wins. When I can I use Lemo.
Which Bluesound device do you have?
Hi Jean-Paul,
It's a Node 2i. I use them on Ethernet. When it worked it sounded very good.
It wasn't very old (less than a year), stopped being recognised and a few other issues. I know it probably needs the power supply rebuilt. Probably one of the most expensive pieces of junk I ever bought. Knowing that its connected to NAD makes sense.
Absolutely cheap wins! WHat is needed is some industry oversight to keep manufacturing people from doing things they shouldn't. Still, it is up to the user to ensure the external power supply is the correct one. If it was a laptop I'm sure more care would be taken. I'm talking everyone in general. mrgarison is by no means alone here.
It's a Node 2i. I use them on Ethernet. When it worked it sounded very good.
It wasn't very old (less than a year), stopped being recognised and a few other issues. I know it probably needs the power supply rebuilt. Probably one of the most expensive pieces of junk I ever bought. Knowing that its connected to NAD makes sense.
Absolutely cheap wins! WHat is needed is some industry oversight to keep manufacturing people from doing things they shouldn't. Still, it is up to the user to ensure the external power supply is the correct one. If it was a laptop I'm sure more care would be taken. I'm talking everyone in general. mrgarison is by no means alone here.
For sure!
Had I known they were related to NAD in any way, I would never have bought it. I got it when they were first out. It's been in a closet for a while now. Paperweight.
Had I known they were related to NAD in any way, I would never have bought it. I got it when they were first out. It's been in a closet for a while now. Paperweight.
Now I recall what I was doing before. I was running a web platform on my raspberry pi connected to the DAC via usb. It sounded great. That was instead of using Bluetooth.