S300 NAD
Hie I am very happy to say my S300 works again because of you. I applied all what you said and with the schématic, and time all is ok. Thank you so much.
You won't find equivalents to ZTX653/753 that have the same pinout, size and 2W rated dissipation.
Mouser and many other distributors sell these components. However, as the thread shows, the more likely faults are general failures of solder joints in the area discussed.
ZTX653 Transistors bipolaires - BJT | Mouser
Composants électroniques | Pièces électroniques | Farnell France
Mouser and many other distributors sell these components. However, as the thread shows, the more likely faults are general failures of solder joints in the area discussed.
ZTX653 Transistors bipolaires - BJT | Mouser
Composants électroniques | Pièces électroniques | Farnell France
Hi guys.
Small question, maybe someone can help.
My friend has got one issue with s300, but it seems not to be discussed problems with diodes blinking or noise in one chanel.
The boards have no signs of overheating near to the crucial resistors and transistors. All looks fine except poor soldering quality (were these first experiences with lead-free solder?? damm, this look really poor)
The AMP normally is working fine, but sometimes the volume level of one channel is suddenly raising slowly but... to the top. So you have to trun off the amp quickly, as it probably kills the speaker. So you can use it, but this is stressfull
Small question, maybe someone can help.
My friend has got one issue with s300, but it seems not to be discussed problems with diodes blinking or noise in one chanel.
The boards have no signs of overheating near to the crucial resistors and transistors. All looks fine except poor soldering quality (were these first experiences with lead-free solder?? damm, this look really poor)
The AMP normally is working fine, but sometimes the volume level of one channel is suddenly raising slowly but... to the top. So you have to trun off the amp quickly, as it probably kills the speaker. So you can use it, but this is stressfull
As only one channel is affected, this is likely just another symptom of poor soldering - perhaps even near the volume control. The best solution if you are unsure how to trace faults, would be to simply reflow all the joints on the input selector and gain stage (the signal handling sections) of the main PCB. Sure, it's time consuming but at least it doesn't involve a lot of discussion about "possibilities" and reduces the chance of other future problems too.
You could also try tapping around the board, using freezer spray etc to see if it provokes the fault so you can identify it but that may just be wasting time that could be spent on a general overall improvement.
You could also try tapping around the board, using freezer spray etc to see if it provokes the fault so you can identify it but that may just be wasting time that could be spent on a general overall improvement.
That's a good question. The last time I bought any was years ago when a specific Freon or CFC, which is non-flammable, was still in use.
Here's an MSDS of a generic brand freezer spray sold by CPC-Farnell in the UK: http://www.farnell.com/datasheets/609177.pdf
As you can see, the data is vague and probably confusing to experts too. It's gloriously non-specific and useless for anything but a handwaving description of any clear liquid but it does indicate that the contents are largely tetrafluoroethane (non flammable) with a small percentage of dimethyl ether (very flammable). It's a mixture though and the tetrafluoroethane (TFE) will inhibit any burning or explosion as it's used in some fire extinguishers, IIRC and of course, it's the monomer from which PTFE or Teflon polymer is made. Interesting, they must have plenty to spare to use it for freeze spray.
Whilst that would not suggest any problems in use with a powered board, I would try to use the method of carefully dripping the liquid onto components, one at a time as frequently advocated here by Mooly. I doubt you will get a lot of sense out of spraying everything in sight at once - You need to target just a few individual parts and that also contains any safety risks.
Yep Spraying all the board at once would be pointless.
I've noticed this product:
http://media.wuerth.com/stmedia/shop/masterpages0000/std.lang.all/06539.pdf
I had good experience with Wurth products before, especially HSS2000 grease spray for my bicycles' chains. It killed all the expensive fancy label products for bikes...
Finally, I guess he will send this amp to some service specialized in the repair of amplifiers. I am building devices, but transistor amp's repair is some different pair of shoes and I guess they have their special tricks and they won't be reinventing the wheel in case something goes wrong
Spraying all the board at once would be pointless. I've noticed this product:
http://media.wuerth.com/stmedia/shop/masterpages0000/std.lang.all/06539.pdf
I had good experience with Wurth products before, especially HSS2000 grease spray for my bicycles' chains. It killed all the expensive fancy label products for bikes...
Finally, I guess he will send this amp to some service specialized in the repair of amplifiers. I am building devices, but transistor amp's repair is some different pair of shoes and I guess they have their special tricks and they won't be reinventing the wheel in case something goes wrong
Many years later...
...I'm the recent owner of a NAD S300. Well, great amp, it sounds mighty and gentle at the same time. But of course I'm worried about the future. The unit has never been updated. I checked inside and there are no discolouration and everything seems to be alright. But a strange thing happens when I turn on the amp: the blue led flash for 5 or 6 seconds, then the led off and the amp works properly. I was thinking that maybe the amp was doing a kind of check before use. But now, after reading this old post, I'm afraid that something's going bad!
Thanks for your attention and a great CIAO from Roma!
Edoardo
...I'm the recent owner of a NAD S300. Well, great amp, it sounds mighty and gentle at the same time. But of course I'm worried about the future. The unit has never been updated. I checked inside and there are no discolouration and everything seems to be alright. But a strange thing happens when I turn on the amp: the blue led flash for 5 or 6 seconds, then the led off and the amp works properly. I was thinking that maybe the amp was doing a kind of check before use. But now, after reading this old post, I'm afraid that something's going bad!
Thanks for your attention and a great CIAO from Roma!
Edoardo