How can I trouble shoot please?
Troubleshooting depends on what skills and tools you have. Since the fuses are located inside the amp, then I take it you're comfortable with removing the lid and poking around inside.
So, taking the usual mains power safety precautions....
Check that power from the wall socket is getting through to the amp. Use a multimeter to check the mains voltage as it comes in from the power cord. Also check the power is getting through the mains switch and on to the power supply board.
Disconnect the speakers and then power up the amp. If it comes on, then you've probably got either a cabling or speaker issue. Double check by trying the amp volume (no source, no speakers) and ramp it up slowly to 100%. If the amp still stays on then look at your speakers.
Connect one speaker, add a source of music. Power up and check the volume again but to about 1/3rd volume. If the amp cuts out then you found the bad speaker/wiring. If it ran okay then try with the second speaker attached. Repeat as before.
If the amp won't fore up with no speakers attached then something is either worn out or blown inside. Disconnect the live mains feed. Be careful of any capacitors. They will probably be holding charge.
Do a visual inspection. You're looking for capacitor bulge (Google it) or obvious signs of a diode, resistor or transistor having either blown or overheated.
Thank you very much Lucid AV. Two of the capacitors seem to be slightly convex on top while the other two are somewhat concave. The main Board id\s so covered in adherent dust that it is difficult to see transistor damage. Is it the underside I should be looking at or the top and is there a safe way to clean it?
Capacitors can bulge from either the top or the bottom. As for dust, first thing I do is take a device outside and blow it out with an air line. Then I'll use Switch Cleaner/Contact Cleaner sprayed on bits of the board where I need to work and rubbed aroud with a small paint brush. I don't see much point in trying to clean up an old board completely.
Most PCBs are populated from one side and then the solder connections are made on the other. So if looking for blown components, quite obviously, you need to look at the component side.
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SOURCE: NAD C270 amp won't switch from red power/protection to green.
The AH may denote "slo-blo" style as opposed to Fast-acting
A fast-acting fuse will look like a single strand of wire ( maybe wiggly looking) ..A Slo-blo will have an element in it and a spring
SOURCE: Yamaha DSP-A2070 not working, and not power up in standby mode. All the fuses is OK. Please help ?
start reading on page 14 of your service manual.
let me know if you need further assistance!
Testimonial: "Thanks for your suggestion. Rommel. I've found that the crystal XL2 didn't oscillate on IC35, and i have replaced the crystal and the unit managed to power up, but after switching the first Relay, and then go back to sleep again. It looks like maybe the two Amplifier Relays faulty or the driver chips for the Relays faulty. I remembered before the unit gone dead, it has this same problems. When i till the unit on side way, sometimes the two Amplifier Relays will clicks, and the unit will work happily. If you have any input into this problems, i will be glad to hear from you. If not, i will try to get those 2 Relays replace, and see that will fix the power up problems. Thanks for your input. "
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I was playing the audio rather loud when this happened. Has been used infrequently before this.
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