Orion hcca 250r and 225r grounding out

[ash4kel]

Attached are photos of the two amps. I have attempted to power the 250r only. The fuse blew immediatly on on contact. At this point I checked continuity from the ground lug of amp to the circuit board side of the fuse buss. I then checked continuity and had continuity from ground to all legs of the NDP7060's. (side note: the 225r also has continuity between the ground lug and circuit board side of fuse, and continuity to ground on all three legs of two of the NDP7060, and on two legs on five of the NDP7060's and 0 continuity to ground on the other last two NDP7060,s. Obviously I do not have consistency and I am assuming that I should not have continuity to ground on all of these. Please let me know what I should be seeing or if I am looking at the wrong thing. Thanks

 

[Perry Babin]

No. You should not read 0 ohms between any legs of any of the power supply FETs. You'll need to remove them to check them. To remove them, apply enough new solder so that you can heat the connections for all 3 legs at once. They should fall out when the solder is hot enough.

 

[ash4kel]

Thanks Perry, One FET was bad and now it works. I will have to get some more 7060,s to replace the bad one on the 225r and test it. Thanks again

 

[Perry Babin]

You need to replace ALL of the 7060s if you want the amp to be as reliable as possible.