Which of these posts lists your questions?
So, the NAD 701 went into protection mode.
When?
Before you changed components? Or after you changed components?
Before you connect speakers, or after you connect speaker/s?
Both channels?
hi this is the 701 board, it looks fine with no burning, no smells nothing it all looks like new, the small green .1 uf caps was swollen so changed them, the output transistors are new one's so when i change the rest it should work, i just need to mod the underneath with the resistors for the thermal stability, and thanks for all the help by the way, love these amps hope i can sort it out i had the 3020 years ago with diamond 2's which i managed to get the other month for 20 quid like new(bit of nostalgia kicking in) and they sound great.
its compressed so think its worked now
I did read the whole Thread.
So, the NAD 701 went into protection mode.
When?
Before you changed components? Or after you changed components?
Before you connect speakers, or after you connect speaker/s?
Both channels?
Protecton
Thanks Andrew for your reply, and sorry let me start over, I bought the amp nad701 got home plugged in speakers and turned it on used it for about an hour, turned it on two days later and noise ? Very quiet then went into protection mode, I had a read around on this forum and ordered the transistors 3055 & 2955 two of each changed them and still the same except the noise it made was a little louder and it seemed to stay on without speakers plugged in, since then I have changed more components and I'm still waiting for a set of transistors to get here so I got the shematic again on here and tested lots of resistors & diodes (out of circuit) all seem ok apart from one 180ohm Which fried when I put in a new fuse so changed that, that's all I can do or say for now until I get the other parts changed ?. Thanks for any forth coming help
Thanks Andrew for your reply, and sorry let me start over, I bought the amp nad701 got home plugged in speakers and turned it on used it for about an hour, turned it on two days later and noise ? Very quiet then went into protection mode, I had a read around on this forum and ordered the transistors 3055 & 2955 two of each changed them and still the same except the noise it made was a little louder and it seemed to stay on without speakers plugged in, since then I have changed more components and I'm still waiting for a set of transistors to get here so I got the shematic again on here and tested lots of resistors & diodes (out of circuit) all seem ok apart from one 180ohm Which fried when I put in a new fuse so changed that, that's all I can do or say for now until I get the other parts changed ?. Thanks for any forth coming help
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Build a Mains Bulb Tester.
It will let you power up the damaged amplifier without damaging any more components.
If the amp draws too much current the bulb lights up and the voltage going to the transformer primary is massively reduced.
You end up with a secondary voltage feeding the PSU of just a few volts.
This lets you check the PSU for faults.
Measure the PSU voltage and if you can get in, measure the two amplifier voltages.
This is 6 measurements in total.
You would need to disconnect the two amplifiers and then power up again. This should allow full voltage to the PSU. Measure and report.
It will let you power up the damaged amplifier without damaging any more components.
If the amp draws too much current the bulb lights up and the voltage going to the transformer primary is massively reduced.
You end up with a secondary voltage feeding the PSU of just a few volts.
This lets you check the PSU for faults.
Measure the PSU voltage and if you can get in, measure the two amplifier voltages.
This is 6 measurements in total.
You would need to disconnect the two amplifiers and then power up again. This should allow full voltage to the PSU. Measure and report.
Sirius,
Please please try seperating your posts out into paragraphs, like Andrew (above) has. The big blocks of text are offputting at the best of times - imagine seeing a huge wall of, for example, French with no obvious breaks. Unless you had to, you just wouldn't bother trying to read it.
To give you an idea, here's your previous post:
" Thanks Andrew for your reply, and sorry let me start over,
I bought the amp nad701 got home plugged in speakers and turned it on used it for about an hour, turned it on two days later and noise ? Very quiet then went into protection mode,
I had a read around on this forum and ordered the transistors 3055 & 2955 two of each changed them and still the same except the noise it made was a little louder and it seemed to stay on without speakers plugged in, since then I have changed more components and I'm still waiting for a set of transistors to get here so I got the shematic again on here and tested lots of resistors & diodes (out of circuit)
all seem ok apart from one 180ohm Which fried when I put in a new fuse so changed that, that's all I can do or say for now until I get the other parts changed ?.
Thanks for any forth coming help "
Please please try seperating your posts out into paragraphs, like Andrew (above) has. The big blocks of text are offputting at the best of times - imagine seeing a huge wall of, for example, French with no obvious breaks. Unless you had to, you just wouldn't bother trying to read it.
To give you an idea, here's your previous post:
" Thanks Andrew for your reply, and sorry let me start over,
I bought the amp nad701 got home plugged in speakers and turned it on used it for about an hour, turned it on two days later and noise ? Very quiet then went into protection mode,
I had a read around on this forum and ordered the transistors 3055 & 2955 two of each changed them and still the same except the noise it made was a little louder and it seemed to stay on without speakers plugged in, since then I have changed more components and I'm still waiting for a set of transistors to get here so I got the shematic again on here and tested lots of resistors & diodes (out of circuit)
all seem ok apart from one 180ohm Which fried when I put in a new fuse so changed that, that's all I can do or say for now until I get the other parts changed ?.
Thanks for any forth coming help "
new parts
hi sorry for the delay, the bits I ordered came from china and took weeks. anyway there all in now built my self a bulb tester and plugged in, bulb lit up and resistor 453 (180 ohm) fried again, can anyone throw any light on this or may be give me a place to start shem 2 is the part I think is the problem, thanks
hi sorry for the delay, the bits I ordered came from china and took weeks. anyway there all in now built my self a bulb tester and plugged in, bulb lit up and resistor 453 (180 ohm) fried again, can anyone throw any light on this or may be give me a place to start shem 2 is the part I think is the problem, thanks
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