zen v1 build problems????

[fligti91]

right they are flipped on opposite sides of the board, right?

[Magura]

Originally posted by fligti91
here is my heat sink, how do you think ill be with this?

That is not much for two channels. You are going to dissipate close to 300W of heat, if you stick to the 0R22, as in 3A bias.


I used something like 6 or 8 times that, and still I had it running at the wrong side of good.


Magura

[Magura]

Originally posted by fligti91
right they are flipped on opposite sides of the board, right?

Yes, so the trick is to figure which is which, hence the trick about looking for where R1 is connected.


Magura

[fligti91]

holy crap! ill have to order some higher value resistors then

[Magura]

Originally posted by fligti91
holy crap! ill have to order some higher value resistors then

Don't you have some extras of the 0R22 ?


Magura

[Iain McNeill]

nicely sleuthed Magura

[fligti91]

ok so i powered it up with the pins soldered correctly. the 6 amp fuse blew right away. so i disabled one channel and the fuse didnt blow. and i checked for voltage at the drains and found 22v(half of the input). after letting it sit for a minute like that i came back to it and found the drains to be at the same as the input voltage 43v. this is driving me nuts! i obviously screwed up the mosfets wiring originally but now im thinking i blew them because of it???
you all have been a great help and have already shown me where i was wrong, please dont give up on me, lol.

[Magura]

Originally posted by fligti91
ok so i powered it up with the pins soldered correctly. the 6 amp fuse blew right away. so i disabled one channel and the fuse didnt blow. and i checked for voltage at the drains and found 22v(half of the input). after letting it sit for a minute like that i came back to it and found the drains to be at the same as the input voltage 43v. this is driving me nuts! i obviously screwed up the mosfets wiring originally but now im thinking i blew them because of it???
you all have been a great help and have already shown me where i was wrong, please dont give up on me, lol.

I didn't give up on you, but we have a few hours time difference.


Does the voltage at the drains change at all when turning the potentiometer?

Usually when running mosfets this hard, you have little doubt if they're goners, but it's been seen that they die silently.

The easy solution (if you have the parts) is to replace the mosfets. The a bit more complicated solution, is to remove the mosfets from the circuit and test them.

Here is a guide: http://www.passdiy.com/pdf/mos.pdf


Magura

[fligti91]

would you all have a recommended part number for an inductor to use on my 43v to bring it back down to the 34 v the circuit was designed for? im going to have to order some new mosfets and power resistors

[Magura]

You can't reduce the voltage that much with an inductor, but the voltage is not really a problem. I usually play with stuff like this, pushed about as hard as you do here.

Just order some 0R33 and 0R22, and a bunch of mosfets, since you're going to build something more fun later anyways
A few MPSA92 may also come in handy.

Magura