Hello Hans
Have you checked the continuity of the primary windings of your amp's tranformer?. You have already stated that your amp went dead. If it is so, there must be some fault inside it, a fuse is blown, a shorted rectifier, a shorted filter capacitor, shorted output transitors or so. If so the mains fuse will blow out. have it happened in your amp?
Anyway the colour code cannot be predicted as Nad has different colour codes used for their primary winding input to their transformers. You just do one thing. The transformer primary have tappings in it, to input various voltage inputs, and that tapping are comming out in different colored wires. Measure the resistance of the winings, with a multimeter set to ohms range. One end of the winding will be direct, and the other end is tapped for different voltage inputs. The maximum resistance winding which you gets with respect to the common direct end will be meant for 240V, and next lesser meant for 220V. Leave the other ends free, and insulate its ends without touching each other, or touching in on the chasis. OK.
Hello Hans
you dont go for voltage measurments on these leads, as all of them will give you the sam voltage, bacause the there is only a few turns of windings extra to bear in between them. You just insist on resistance measurment. Find out the common lead, and measure the resistance. A digital multimeter is preferred, because the primary winding of your amps transformer will have very low resistance, say Ohms. Set the multimeter to Ohms range and measure the resistance of all the taps, with respect to common. As i stated earlier, the highest resistance showing tap is meant for connecting 240V, to the next less meant for connecting 220v, and you needs this winding only. If you have set the selector tap to lower voltages earlier, when it is connected with selector switch,there is a chance to open the main winding. If so transformer should have to be rewined.Ok
Hello Hans
I'll give you one more clue to get the 220V winding in your Nad Amps' transformer
Suppose we have a small transformer with 110V,120V, 200V, 220V, 240V tappings in its primary windings. We can get these windings by measuring Ohms [resistance] of the winding. I'll give you a guess, to get value of resistance.
0V====> 110V = 50 Ohms approx
0V====>120V = 55 Ohms approx
0v====> 200v = 60 Ohms approx
0V====> 220v = 65 Ohms approx
0V====> 240v = 70 Ohms approx
Where 0V lead is common, which may be coloured black in most transformers.
The above said is not exact values, and are given to you for a guess, when you measure the resistance value of the windings of your amps' transformer.
0V====> 240v - 70 Ohms approx
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Hello and thank you for your advice!!
When the amp went dead (no diode indicators) no fuses were blown. I read that a common problem with the NAD 2200 is the input voltage selector. So I opened it up; it was very losely fit and 2 connector blades fell out. I found one 220V cable (among the 6 cables atached to the voltage selector) and soldered it to the cable I assumed was the 220V winding. The diodes then lit up for a fraction of a second and the main fuse (5A) blew. This is what made me convinced that the problem really is in the voltage selector. Do you think I am right about that?
The input voltage selector can be configured for 110/120/220/240V - 4 states.
There are 6 cables attached to the voltage selector, where 3 of them measure 220V (when soldered free). The other 3 cables measure around 9-12V AC. I would assume I should have 4 tapping wires, one for each input voltage, and only one 220V feed wire, to attach to one of the four tapping wires. But that doesn't seem to be the case. Or am I wrong?
I will try to find the direct winding (for reference) on the transformer to do the resistance measurement, as you suggest. But the 6-wire setup of the voltage selector, with 3 of them having 220V with all 6 wires soldered free, makes me a bit confused of the function.
Kind Regards,
Hans.
Hello and thank you for your advice!! When the amp went dead (no diode indicators) no fuses were blown. I read that a common problem with the NAD 2200 is the input voltage selector. So I opened it up; it was very losely fit and 2 connector blades fell out. I found one 220V cable (among the 6 cables atached to the voltage selector) and soldered it to the cable I assumed was the 220V winding. The diodes then lit up for a fraction of a second and the main fuse (5A) blew. This is what made me convinced that the problem really is in the voltage selector. Do you think I am right about that? The input voltage selector can be configured for 110/120/220/240V - 4 states. There are 6 cables attached to the voltage selector, where 3 of them measure 220V (when soldered free). The other 3 cables measure around 9-12V AC. I would assume I should have 4 tapping wires, one for each input voltage, and only one 220V feed wire, to attach to one of the four tapping wires. But that doesn't seem to be the case. Or am I wrong? I will try to find the direct winding (for reference) on the transformer to do the resistance measurement, as you suggest. But the 6-wire setup of the voltage selector, with 3 of them having 220V with all 6 wires soldered free, makes me a bit confused of the function. Kind Regards, Hans.
In this thread I found the clue to solve the same problem I had in my NAD 2200 amp. I solved it by bypassing the broken imput voltage selector. I only need 220V so I soldered a small piece of wire between the red and green terminals. These are the connections for the others voltages (as they operate in the imput voltage selector):
110V: (Brown-Green)-(Red-Blue)
120V: (Yellow-Brown)-(Orange-Blue)
220V: Green-Red
240V: Yellow-Orange
I have pictures and diagrams of the broken imput voltage selector and the bypass of it, If anybody need them.
Regards
I had the same problem- simply bridge the voltage selector. The contacts get burned out.
I also had the same problem to this, is that any one has update on the connection to 220V?
Green-Red is OK or not?I don't know how to measure the resistance of those wire cause all is almost same as 1 to 1.5 ohm.
Thanks and regard
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