hifonics zeus xi

[mike49504]

im working on a hifonics zeus xi amp the problem im having is there is a cap in the amp that keeps blowing when the amp is powerd up i checked all outputs and fets all check fine checked the diodes all fine but the cap is 47uf 16 v i put a new one in and in about 15 20 secs it blows the cap wondering what i should check the cap is towads the output side and also there is 2sa1987's in the amp but someone put in a couple 2sa1943's and 2sa1987's wondering if this is gonna work or should i put in all 2sa1987's and the outputs were 2sa5359's and someone told me they should be 2sc5200's is this corect?? any help would greatly be appericated

[mike49504]

somemore looking at the amp i believe the cap that keeps blowing is in the muting circuit if that helps

[Perry Babin]

Pull the cap and measure the voltage across the pads when it's powered up. Is it higher than 16v?

Also check the polarity on the pads to make sure that the capacitor is being installed properly.

[mike49504]

i put leads across pads its reading 38.56 volts across the pads

[Perry Babin]

Are you sure the original cap wasn't rated for 50v?

Does the amp work properly without the capacitor?

[mike49504]

the original cap was the same 47uf 16v amp does not work protection light is on

[Perry Babin]

Can you send me a few photos of the amp board and the location of the cap so I can see if I have any information on it or a similar amp?

[I Am An Idiot]

From Ampguts

[mike49504]

further looking at the amp i came across the njm2068l low noise dual operational amp the reading i got from one are


pin1:13.78v

pin 2:13.63v

pin3:13.79v

pin4:-0.047v

pin5:13.79v

pin6:35.12v

pin7:0.69v

pin8:nothing

wondering if this is bad all the other njm2068l's are showing a reading of 13.80v on pin 6 wondering if the one in queston is bad making the cap blow

[Perry Babin]

Pin 8 should have approximately positive 15v (13.8 is close enough). Pin 4 should have approximately negative 15v.

Determine why pin 4 doesn't have negative 15v.