Sapare power transformer for a NAD 3240PE

What you are talking about is rebuilding the power supply for the turntable. A tricky job. Can you not find a replacement transformer?
Otherwise you could find a pre-built power supply, providing it has the correct secondary supply for the turntable.

You should check for dry joints near the amp ic.
You should also check R414, R424, R441, R442, R413, R423, R445 and R446.

Hope this helps.

If 220 volts was connected to it, you might be looking at a few parts to repair that wont be available. It looks like the main power transformer and line input transformer are no longer available.

Crackling is usually a dirty control. Try using an electronics cleaner (with lubricant) and spray out all of the controls and switches. With the unit off, work the controls and switches back and forth to "spread" the lubricant. I would spray, work and spray again.

Update this with the results and also see if the crackling is related to the overall volume level. If tied to the volume level, there could be a transistor inside that is breaking down and causing distortion.

Dan

Hi...

Have you checked the rectifier diodes / bridge rectifier . Most DMMs have setting where you can test for forward voltage drop on a diode
0.300- 0.800v depending on the type. If it reads nothing , swap the meter leads.
Also check the leads coming from the power transformer and see if there's continuity. THey will read low value ohms

The output should be 24v ac. Sounds like you have a busted transformer. Did you check out the resistor in front of the transformer.

You sound like you know what your talking about so I will not bore you with suff like glass fuses and thermal couples.

Good luck, I have had a few items like this over the years. Sometimes it's just best to send them in to the manufacture. I would look for a replacement transformer. 120v ac to 24v ac around 5 amps. Test it out and see if it works... If not, send it in.

Solution if all fuses checked out OK and +/-40V are present on main PCB DC connector from power supply:
Check for +37V and -37V on small sub-power supply PCB - mounted vertically on the main power supply PCB. (next to ribbon cable connector is a layout with voltages.) If the +/-37V are missing check (replace) C501 (0.1uF) on the small power supply PCB for leakage, but also check (replace) R401 (2R2) and R402 (2R2) on the main power supply PCB. Both resistors are fuse-resistors and will have gone open circuit when C501 has gone leaky.

You should repleace the old transformer with the new one

Check fuses mounted near transformer . If blown check output transistor. Also check transistor transistors on small heat sink . they will cause fuse to blow.

sounds to me that the vol control has lost its earth end connection So yes its a problem with the dial control You couls try some contact cleaner But better still lift of the lid and base if possible while the amplifier is not plugged into the power socket and see if you have a dry joints around the vol control pot regards Trev