Fixed/Fried My Amp!!!

[620hpcrx 10+ year member]

Okay so About a month ago my Tsunami GXA1000d blew...it was only a small transitor that was in the signal path. I ordered the part off ebay $2.25 total and it took 3 weeks to get here from Quebec. I soldered it in (first time soldering components) but the joints turned out nearly perfect. I also put some new thermal contact goop (it was actually some non hardening gasket adhesive). Turns out a little got onto the first N-Channel transistor and shorted it. I go install it and right when I put the main fuse back in I look in the trunk and the shit is smoking like no other!!! I take it back apart and find all the N-Channels and fried! So now I need 10 IRF-Z44N transistors which will cost me $13 shipped off Ebay or $25 shipped off PartsExpress. But I have one question...All of the N-Channels should be the same part right? Im not sure because on 4 of them the sinks melted the transistors to where I cannot read the model number. Also I would like any advise from KNOWLEGEABLE members of the board on replacing these. I have read on biasing but I have no clue how as there are no variable resistors which you can adjust. Any feedback is welcome but please keep unneeded comments to yourself. BTW this was a great learning experience

Shawn

Click to read more...

 

[Death By Bass 10+ year member]

are these mosfets in the powersupply, or the actual amp section itself?

its a class D amp, but generally, they'd only be in the powersupply.

do you have a pic of the internals?

 

[revrider1 5,000+ posts]

are these mosfets in the powersupply, or the actual amp section itself?
its a class D amp, but generally, they'd only be in the powersupply.

do you have a pic of the internals?

//content.invisioncic.com/y282845/emoticons/iagree.gif.15d6c075ee8d3913ba26866d06993068.gif

 

[620hpcrx 10+ year member]

They are definally in the power supply because I didnt even have my car on to activate the remote switch. Ill get back with some pics I need to have a friend come over with his camera...Here is a pic off realmofexcursion... http://ampguts.realmofexcursion.com/Tsunami_GXA1000D/inside1.jpg

It is all of the ones on the bottom of the pic.

 

[Death By Bass 10+ year member]

They are definally in the power supply because I didnt even have my car on to activate the remote switch. Ill get back with some pics I need to have a friend come over with his camera...Here is a pic off realmofexcursion... http://ampguts.realmofexcursion.com/Tsunami_GXA1000D/inside1.jpg
It is all of the ones on the bottom of the pic.

yeah, no worries, they would all be the same Z44 mosfets then...

EXCEPT!!! the stuff you used as thermal paste would NOT have caused all those to blow...

maybe there's something else wrong with the amp?

what was the part you originally replaced?

 

[Death By Bass 10+ year member]

oh, BTW, the amp looks alot like a Lanzar vibe 1200D

http://ampguts.realmofexcursion.com/Lanzar_Vibe_1200D/inside1.jpg

lol //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif except, I know that the lanzar uses higher power mosfets in the powersupply...

 

[620hpcrx 10+ year member]

2SC3198 Transistor

...BTW it wasn't electronics paste it was a gasket sealer for automotive use...I tried it because it was non hardening and it can be used up to 400* F. The paste got between the leads on the first transistor and im pretty sure it cause a short...but none of my fuses were fried unlike the first time? The part I replaced exploded when I found it, well prior to when I found it.

 

[Death By Bass 10+ year member]

2SC3198 Transistor
...BTW it wasn't electronics paste it was a gasket sealer for automotive use...I tried it because it was non hardening and it can be used up to 400* F. The paste got between the leads on the first transistor and im pretty sure it cause a short...but none of my fuses were fried unlike the first time? The part I replaced exploded when I found it, well prior to when I found it.

where is that part actually on the heatsink though?

 

[djman37 5,000+ posts]

I'm of the school that the blown piece in an amp was caused by something else upstream. Replacing the blown part doesn't mean the amp is fixed....there's that little problem of what caused that part to blow in the first place. Me thinks you found that out.

 

[620hpcrx 10+ year member]

The part in that picture is left of the two large diodes in the middle on the bottom side of the amp. There are 4 transistors there and it is the bottom left one.

 

[Death By Bass 10+ year member]

The part in that picture is left of the two large diodes in the middle on the bottom side of the amp. There are 4 transistors there and it is the bottom left one.

I have no idea where/what you're talking about //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif sorry. lol

edit: ah right, I think I worked it out lol

 

[Death By Bass 10+ year member]

I believe the mosfets need to be isollated from the heatsink, did you use the original mica stuff? or did this get left out, and is what caused the smoke?

 

[soulstace 10+ year member]

Hi 620hpcrx.

You sound quite knowledgeable at this electronics stuff so I'd like to ask you a question if I may.

I'm having problems with my amp lately too. It emits a high pitch frequency from the amp itself, without any speakers hooked up to it even. If I hook up a speaker then the sound comes out of the subwoofer too! One thing I do know, the crossover doesn't filter it out and I'm afraid it will damage my subwoofers (not good making sub sound like tweeter).

Any ideas what this could be?

Thank you!

 

[Death By Bass 10+ year member]

you're asking the guy who fixed his amp, AND HAD IT BLOW UP AFTER!?!?!?

anyway... it could be the electrolytic capacitors in the powersupply section of your amp are shot, and need replacing... but it might not be that

 

[soulstace 10+ year member]

There is in fact a bulging capacitor near the speaker outputs. It's not leaking anything but it appears to be open. This could be the problem ey?