Tantrum 600.4 Blowing Fuses

eulogious · Post by **eulogious** » Mon Apr 26, 2010 4:13 pm

Ok, so I order up all my parts from digi key

I went down to my local wholesaler, and they usually only get parts from NTE, and NTE doesn't make a MOSFET that would work for me, so I had to order them online. Digikey also didn't have my panasonic rail caps, they were back ordered and won't ship until 5/31, so I didn't get those, but my rail caps look fine, so whatever. I did get the 2200uf input caps, so that will be a good upgrade atleast. I forgot to take my gate resistors in as well, but I should be able to get those locally, resistors are a lot more common than MOSFETs and big ass caps.

So since I found 2 of my output fets bad and most likely the gate resistors for those fets as well, but that should be my only problem correct? The power fets should be ok... I tested the gate resistors and they were all the same and ok. Granted I will not know until I test them/the amp, but most of the time if an output fet goes, it doesn't always take the power fets, correct? Thanks!

Post by **Eric D** » Mon Apr 26, 2010 4:38 pm

Most of the time when the output goes the power supply will follow. Not all the time though.

Also, the previous gain stages may have been affected on that channel with the dead FETs, but you won't know until you get new ones in there.

eulogious · Post by **eulogious** » Mon Apr 26, 2010 11:04 pm

Eric D wrote:Most of the time when the output goes the power supply will follow. Not all the time though.

Also, the previous gain stages may have been affected on that channel with the dead FETs, but you won't know until you get new ones in there.

What should I looking for if the power fets are blown? The same symptoms the amp has now? I know that all my other output fets are good sense I tested them, and I ordered all new ones anyones so I won't have to worry about them anyways, maybe I will just pull the power supply fets and test them as well. Those look a little hard to source though, so hopefully they aren't bad

Anyone know of a good place for the power supply fets? I will search harder, but any tips would be helpful.

The previous gain stages? Where might I look for that and what exactly should I test?

Thanks for all the help so far, I know I wouldn't be this far without a little bit of help, so thanks a bunch!

eulogious · Post by **eulogious** » Tue Apr 27, 2010 12:32 am

Ok so after some extensive searching and cross referencing cross referenced parts I think I found a substitute for my power fets that I can buy and actually get because it's in stock.

Here's my original:

http://search.digikey.com/scripts/DkSea ... -2770-5-ND

And here's the one I found for a replacement:

http://search.digikey.com/scripts/DkSea ... NDP7060-ND

Apparently the STP60NE06-16 mosfet is discountinued, hence why I was having a hard time finding a suitable replacement.

Here's some info I found in looking for a replacement power fet and what numbers are important:

Things to look out for when finding a match are Vdss (you want higher or same), Rds (lower or same), and Gate capacitance (lower or same).

Does this sound right? That's how I came up with my replacement using that rule. Let me know if these will work to replace my power fets if they are bad. Thanks!

valeks1 · Post by **valeks1** » Tue Apr 27, 2010 11:55 pm

Ref# for Output FET's please

eulogious · Post by **eulogious** » Tue Apr 27, 2010 11:58 pm

valeks1 wrote:Ref# for Output FET's please

?? What exactly do you need? If you need the part numbers off the original fets and can't see them in the pictures I have provided and really need them, I can get those for you later (I am at work now), other than that the links I have above should have all the info you need...

eulogious · Post by **eulogious** » Wed Apr 28, 2010 3:27 am

Ok, so I am trying to figure out what resistors to get for my output gate resitors, and I just want to verify that I got this right, sense it seem like a very little resistance to me, but what do I know?

So my gate resistor colors are brown, black, silver, gold, and if I have done my research and math right, that should only be .1 ohms

That seems low, but is it correct?

Also what wattage are those resistors?

There really doesn't seem to be a way to figure that out easily...

Once I remove the gate resistors I will just take them to my local shop and see what they got, but incase I don't make it, I would like to know what to get without having to physically take something to someone. Thanks!

Post by **Eric D** » Wed Apr 28, 2010 5:30 am

Are those the output gate resistors, or the power supply gate resistors?

eulogious · Post by **eulogious** » Wed Apr 28, 2010 5:40 am

They are the output gate resistors, the power supply ones are super small I believe. The resistors I am asking about are the ones that are in the circuit for the output fets, the ones that are blown on mine.

eulogious · Post by **eulogious** » Wed Apr 28, 2010 5:42 am

These are the exact ones:

Post by **Eric D** » Wed Apr 28, 2010 5:54 am

Those are not gate resistors. They are for the drain or the source, depending on the design of the amp. You need to look for some 1/4 or 1/8 watt resistors attached to the gate pins of those MOSFETs.

eulogious · Post by **eulogious** » Wed Apr 28, 2010 5:59 am

That would explain some of my confusion, thanks

I will look closer, I just figure with high powered fets, bigger resistors. You know what happens when you assume

I should have guessed with the power supply fet resistors being small and all

When I get home I will check the board more closely and post back.

Post by **Bfowler** » Wed Apr 28, 2010 10:01 am

here you go: check those ones

eulogious · Post by **eulogious** » Wed Apr 28, 2010 10:56 am

Cool, thanks for the heads up on those. They tested fine. I also tested just about every resistors that was close to any of the gates for any of the fets, and then I tested around those just to make sure, and everything else tested fine.

I then spent some time taking off the power fets and testing them and then putting them back on. I also reinstalled the rail caps, and I "touched up" any old looking solder joints, or any joints that looked like they got really hot. Figured it couldn't hurt to let the solder resettle/rebond in those places.

So the only transistors that I did not check are the four that aren't directly related to the power or the output. It would seem that those two output fets were what was making my amp blow it's fuses. Now I just have to wait until my new parts arrive and install them and see if it works!

Is there anything else that I should be looking for while I wait for my parts (they should be here by Friday I hope)?

Post by **stipud** » Wed Apr 28, 2010 11:00 am

Not sure if you've done it yet, but you should check the power supply FETs for posterity, just to make sure that the shorted output didn't cause any of them to fail. Would be a major pity if you replaced your output fets only to have the powersupply fry them all!

No comment on which model would be a suitable replacement... let's just hope it doesn't go that far.

eulogious · Post by **eulogious** » Wed Apr 28, 2010 11:04 am

stipud wrote:Not sure if you've done it yet, but you should check the power supply FETs for posterity, just to make sure that the shorted output didn't cause any of them to fail. Would be a major pity if you replaced your output fets only to have the powersupply fry them all!

No comment on which model would be a suitable replacement... let's just hope it doesn't go that far.

eulogious wrote:I then spent some time taking off the power fets and testing them and then putting them back on. I also reinstalled the rail caps, and I "touched up" any old looking solder joints, or any joints that looked like they got really hot. Figured it couldn't hurt to let the solder resettle/rebond in those places.

eulogious wrote:Ok so after some extensive searching and cross referencing cross referenced parts I think I found a substitute for my power fets that I can buy and actually get because it's in stock.

Here's my original:

http://search.digikey.com/scripts/DkSea ... -2770-5-ND

And here's the one I found for a replacement:

http://search.digikey.com/scripts/DkSea ... NDP7060-ND

Apparently the STP60NE06-16 mosfet is discountinued, hence why I was having a hard time finding a suitable replacement.

One step ahead of you smokey

(from my previous posts)

Post by **stipud** » Wed Apr 28, 2010 11:42 am

Sorry missed the point where you already tested them.

Sounds like you are close to getting it bumping again!

eulogious · Post by **eulogious** » Wed Apr 28, 2010 11:46 am

stipud wrote:Sorry missed the point where you already tested them.

Sounds like you are close to getting it bumping again!

It's all good

I am excited to get it going again, and all thanks to the phorum!

eulogious · Post by **eulogious** » Fri Apr 30, 2010 11:08 am

It's Alive, IT'S ALIVE!! I haven't seen that pretty blue eye in a long time

So my parts came this morning, so I threw on the new fets and the bigger caps

The phatty new caps:

New fets:

It's all solder up and ready to be put back together

This is the heat sink stuff I used. I applied it like I would a CPU heat sink, I hope I did that right! Should've though. This is the stuff that doesn't dry as well, so I think it's close to what they use...

Here it is all back together

Just need to add the bottom...

Here's a pic of my "workstation" and my "test bench"

I grabbed my center channel from my home surround just to test for sound, and used my iphone for music...

But it all works! I got music out of all the channels!! YAY!! Now I just need to install in my to to truly say it's fixed

Thanks all for the help, I wouldn't have been able to do it on my own, so thanks! I just saved my amp from the dead!