NAD 3130 rebuilding

[Lynyrd]

All 4 pads shorted

 

[Lynyrd]

All collector pads shorted

 

[Lynyrd]

Without screws no

 

[overall feedback]

The top ones are not important. We are looking bottom ones. Only one, measure, take out, second one, measure, take out...

 

[Lynyrd]

the reason is not in the screws but in the platforms

 

[overall feedback]

Can be housing touching heatsing somehow, or screw touching the heatsink. I bolive that is not the case with all four transistors, but one or two makeing problems. Which one?

 

[Lynyrd]

Only one mesuared shorted,take out not shorted.
Second, mesuared shorted,take out not shorted.....
Third, mesuared shorted take out not shorted
Forth, mesuared shorted take out not shorted

 

[Lynyrd]

All 4 bottom pads are shorted on mass
I desoldered 4 transistors no change

 

[overall feedback]

Could be that you are loading capacitors. Or there is enother short in rectifier or something.

 

[Lynyrd]

I veryfied all resistors and all transistors,all ok.
Capacitors ok.
I don't understand......
The rectifier is also ok
I don't can power on the Amplifier no power transformer on board

 

[overall feedback]

In what exactly case there is not shorted pads?

 

[Lynyrd]

they are always shorted

 

[Lynyrd]

The diod D410 tested on Amplifier is bad, shortcut on mass two side with multimeter
But desoldered he is in good working order.
Strange

 

[Kay Pirinha]

According to your pics in #5 the mandatory isolating bushings appear to be missing.

Best regards!

 

[Lynyrd]

The pads on pcb are shorted