Help me fix Hifonics brutus BXi1206D

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
This amp burned up on me and I was not even pushing it at all. !Can you believe this, I bought this amp for $250 from the local store in february. Warranty on it is 1 year as it says on the box, and the store has return policy of 30 days, so I took it back to the store and they gave me the phone number to call the maxxsonics the company that ownes hifonics, and customer service there tell me they only accept warranties from just one store and that the store that sold me the amp does not exist in their vendors list.

So am screewd by these frauds and junk made in china amp that has american flag on the box a total fraud also. I fixed some MTX amps before an am up to the challange, Perry helped me last time.

I opened the amp and found that some FETs and resistors are shot. As you can see in these pictures: What could cause this?

An externally hosted image should be here but it was not working when we last tested it.


also I have found some oil residue around these capacitors: is that normal?

An externally hosted image should be here but it was not working when we last tested it.


Ok, now, is this all that I need to replace those FETs and those resistors?

Also those metal clips that press on FETs, how do they come off and on?
 
Clips:
http://www.diyaudio.com/forums/showthread.php?postid=1317683#post1317683


You need to check the output FETs. All of the transistors on the opposite are probably outputs.

If the outputs failed, that's what caused the power supply to fail. If they didn't fail, a random component failure in the supply could have caused the supply to fail or there could be another problem like a shorted transformer.
 
In most amplifiers, the only components that show signs of damage when they fail are the power supply transistors and the gate resistors. You generally only have visible signs of damage in the audio section in the really large amplifiers (3000W+).

To give the outputs a quick check, measure the resistance between the legs of the individual transistors. No transistor should have anything near 0 ohms between any of its 3 legs. If you find any that read 0 ohms, they (or a parallel connected transistor) has failed. You'd have to pull them to determine which ones have failed.

If you have any shorted output transistors, there may be damage on the driver board (vertical board near the two large black capacitors). To repair that board, it may take quite a bit of patience because you'd likely have to replace one or more of the surface mount transistors.

What's the number on that driver board, DWM0608?
 
It depends on the part they're using for the outputs (assuming that the outputs failed). The power supply parts will probably be ~$12 plus shipping. You can use a mouser 844-IRFZ44PBF in place of the SFP parts.

The gate resistors are/were probably 47 ohm 1/4 watt.

Before you order parts, you need to remove all of the power supply FETs, clean all of the solder pads up so that there are no solder bridges and power up the amp. You should read ~5v on the side of the gate resistors farthest from the FETs. You probably won't read anything on the other side of a few of the resistors because some are burned and may be open. After replacing the resistors, you should read the same voltage on both legs of the resistors.
 
You need to remove the power supply FETs (all of them) and check for 5v on the gate resistors. If you have ~5v on all of the gate resistors for the power supply FETs, the drive circuit is probably OK. If you don't have ~5v (0v or near 12v), there may be problems with the drive circuit.

When you order parts, order 10 of the IRF640N. You need to order 10 because you're more likely to get matched date codes from distributors with pre-packaged parts (mouser, digikey...).
 
My misstake, I had the battery and I connected the charger to battery, that made the amp to go to PROTECT mode, after I charged a battery a bit, I tested it again with battery alone and am getting rock solid 3.7V on all of them. Is that success? And I tested the 47 ohm resistors and they are all still good, reading 47 ohms
 
So the gamble is to replace all 8 output FETs and all 8 power FETs?
I can go buy this in local electronic shop, they ussualy got more generic items like NTE, I don't care about the quality all I want is to fix this and sell it, am done with these made in china hifonics

so 8 IRF640N and 8 SFP50N06, what would be the most common replacement for these?
Change those resistors too, they are cheap
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.