Thanks. I look forward to learning more about this stuff.

Unfortunately I don't have access to a service manual or schematics...

 

its not about the money honestly

its called being safe then sorry, yes maybe replacing the 2 FETS we blew would fix it, and maybe make it worse and take out other things then, we would have a big *** paper weight

so im just going to send it out and get it done properly and then be good to go!

 

I thought you were coming over?

 

work... wanted to pick it up but got on EC row and forgot till dylan texted me.. i work tomorrow tho!! will get it then if thats ok

 

Bad news Paul, those FETs are expensive and hard to come by. For trouble shooting you could replace each set of paralleled devices with just one cheaper device. You would have to test with a light resistive load of course. If the resistors failed first they may have caused the FETs to fail if they were factored into the dead time calculations. Their failure may have allowed some shoot-through. This is unlikely though, they probably died when the FETs failed. You may still have a shoot-through problem which could come from the drive or modulator circuits. Both require a scope to troubleshoot really. Too bad you're so far away cuz I'd help you out for beer. Do you have access to a scope?

 

I sure do! ...have access to a whole electronics lab. Just need to know what you want me to test and how? Much appreciated Kev.

I know about the shortage. Murilo linked us to some that are in stock for $5 each. Even if I replace all the output FET's and gate resistors I'm still only looking @ around $200 depending on the driver being good.

 

"will work for beer" haha awsome!

Jesse do you know what was previosly repaird?

 

I havent read the whole 7 pages... but here's my 0.02 worth...

remove the burned fets ( if u thi nk u can without burning the board) then using a diode test on your DVM measure the restof the fets that are not POPPED or melted... then check the resistance value across the BIAS resistors closest to the fets... make sure thay are all within 1-2% value or even replacing the fets could just blow them again with improper BIASING
they most likely will be in sets, likely 3 or 4(sometimes more) in parallel then series with another parallel set,
if your diode test shows resiults of 0 that means the internals of the fets are dead short,
look up the data spec sheets on the fets to get an idea of what the readings should be
(its not the most accurate method , but definately does help find most problems) if you remove the blow fets you should be able to turn on the amplifier without it going into protect...
IRFP360 is a very common class D amplifier fet

even ones that don't seem to be burned may have been weakened. my rule of thumb is to always replace the whole RAIL to avoid further damage by weakened fets

 

ALRIGHT! Thanks MTA. Now we are getting somewhere... see there are a few helpful posts.

I think I'm going to replace all the output FET's so long as I can order enough of them. It is my whole parallel line that went on one side. The are 2 sets of 6 output FETs on each side of the amp. Of the 6 FET's in that parallel line, 3 popped and 2 are cracked. I will check over the others too with DVM, but if I can get my hands on 24 of them, I will replace the entire output side for good measures.

 

hahaha, if only he lived a little closer.... we seem to speak the same language.