NCore NC400 Cycling on / off - My Fix

john65b

Member
Paid Member
2005-01-09 2:32 am
Chicago
OK, don't know if anyone has my issues anymore but thought to post anyway

My NCore NC400 with Hypex SMPS600 monoblocks were switching on - off repeatedly, especially on my difficult to drive ML CLS electrostats... I had thought oh, the Class D not playing nice with Electrostats issue...but when it was also doing it on my Maggies, I knew something was up...

After reading the following:

Dead Hypex SMPS600 V3 Power Supplies - notANON

I decided to recap the SMPS power supplies... as it gets somewhat hot and cooks those nearby caps. Being the lazy turd that I am, I just replaced the caps I had on hand, and focused on all the ones under the big heatsink - and yes, you have to remove the heatsink - I changed the three biggest caps - the two big 220v 820uf caps and the 50v 470uf...but on one SMPS I also changed the 35v 220uf (right up against the hot heatsink), and the SMPS other I forgot (it was 2 am).

Anyway, I was happy, but confused as one worked perfectly, while the other SMPS still had issues firing up and staying up.. until I remembered the 35v 220uf I forgot on one SMPS. I replaced it and both are good now.

Also the re calibrate the DC sense on the NC400 with 3 volts on the Mystery 5 pin block on NC400 pins 1 and 2 (neg on 1 pos on 2, with pin 1 closest to the block caps). I had two AAA batteries giving me 2.98vdc that I used, and the amp just stopped - it would no longer produce any sound even though the last cap replacement made it finally fire up and stay up with all LEDs, but sadly, no music.

Then I remembered someone here had done the same thing (two AAA batteries) but used a pair with a bit higher voltage - 3.09 vdc, and it finally worked. So I checked all combination of AAA batteries I had on hand until I got right around that 3.09 vdc and tried it - finally some music.....whew... I had them drive my ML CLS for a few hours at low, then high output and all is good again.

Now if I can just cancel that new SMPS600 from Hypex that I ordered before remembering that one cap I forgot yesterday, all will be really good again...
 
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john65b

Member
Paid Member
2005-01-09 2:32 am
Chicago
Hypex just canceled my order, and they are very interested in my "fix" above.

Hypex customer support just plain rocks!

On a side note, I was thinking I was a bit underwhelmed by the NC400 performance compared to my ICEPower 500ASP monos i have (not really counting the cycling on - off issue), but since replacing those caps, it really sounds great and as good, if not better, than the 500ASP monos.....

I just want to hear them on my Quads next...just need to fix them first....