Electronics > Repair
NAD T513 power supply load !
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guizmo1967:
Hello,

I tried to repair a NAD T513 DVD/CD player that was showing "no disk error". Replacing the laser unit did not solved the problem.

I noticed that the LA6560 Five-Channel Driver was getting really hot but did not bother to replaced it so I gave the unit to a recycle center.

I kept the power supply for learning purpose but it is not working once removed from the player, I think it's because there is no load !

There is only one connector (15 pins)

1   VF+
2   VF-
3   -27VA
4   5.2VA
5   PWR_CTL
6   D.GND
7   5V
8   12V
9   A.GND
10  3.3V(1.8V)
11  3.3V
12  3.3V_M
13  D.GND
14  8V
15  M.GND

My questions are:

Do every power rail needs a load ? If so, which one and what king of load, just a resistor ?

What would you do to make it work outside the player ?

Thank you !

wasedadoc:
I would try loading at least the supply that is monitored in the feedback loop.  Finding a schematic is probably the easiest way of determining that.
guizmo1967:
Here is the schematic of the power supply !
guizmo1967:
Remember, this power supply was working fine when plugged in that DVD player ! I don't have that DVD player anymore, I just kept the SMPS.

I get voltage on the first 4 pins only and it is fluctuating, not stable that's why I think it needs a load.

Do I put a resistor between pin 1 and 2 ???

This is my readings:

Pin 1: -15V (not stable)
Pin 2: -22V (not stable)
Pin 3: -27V (not stable)
Pin 4: +4.98V (not stable)

On the schematic, pin 3 and 4 are marked VA ??
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