Hello all.
I have a MTX Thunder 3404 4ch amplfier here that i am going to attempt to repair myself. I have a basic electronic understanding.
I recieved this amplfier in it's current non-working condition, I have no idea why it failed, But i believe it may have been due to dodgy instalation(earth was glued into position!!(no bolt)
The first issue i found was shorted Output fet's (irf540's) This was causing the amp to continually power up and off again, Fan at full speed.
I removed the shorted mosfet's, Then powerd it up, All went well, Powerd up as normal (minus the 2 shorted fet's that was removed) At this stage everything was working well, But i powerd it down soon after as to not do any further damage. The remaining 540's were starting to get a little warm but i would just assume this was due to having no partner.
Had the amp sitting about a month while i waited for the new IRF540's to arrive in the mail, They arrived but were very badly packaged, No anti static bag.
I installed the 8x IRF540's into the output section, Re-powerd the amplifier up only to see 3x IRF540's go up in smoke, They got super super hot really fast,(matter of seconds) I powerd the amplifer down, Removed the fried-shorted mosfets
Once i had removed the fried 'new' mosfet's, I powerd it back up again.
At this stage, It was doing simmluar to the original fault(power on-off fan at full speeed)
But now, There is 2 little RED SMD LED's right near the RCA input's that are illuminated during the on-off stage, I would assume this is due to further damage?.
At this stage, I have re-orderd 10x IRF540's from a diffrent seller, SO wile i wait for them to arrive, I thought i might see if anyone might be able to help me out, Point me in the right repair direction.
This amp is a real hard one, It's very hard to map the circuitry. I have no scematic, Can't seem to find one on this amp, So i am reapiring step by step in the dark.
Sorry for the big type up, But it's just eaisier to explain all i know
Where should i go from here?.
What are these illuminated RED SMD LED's right near the RCA input's? (on the inside of the amp, Not visable when amplifier is together)
As far as i understand, All MTX Thunder amp's have these SMD LED's in the same position.
???
Thanx all.
I have a MTX Thunder 3404 4ch amplfier here that i am going to attempt to repair myself. I have a basic electronic understanding.
I recieved this amplfier in it's current non-working condition, I have no idea why it failed, But i believe it may have been due to dodgy instalation(earth was glued into position!!(no bolt)
The first issue i found was shorted Output fet's (irf540's) This was causing the amp to continually power up and off again, Fan at full speed.
I removed the shorted mosfet's, Then powerd it up, All went well, Powerd up as normal (minus the 2 shorted fet's that was removed) At this stage everything was working well, But i powerd it down soon after as to not do any further damage. The remaining 540's were starting to get a little warm but i would just assume this was due to having no partner.
Had the amp sitting about a month while i waited for the new IRF540's to arrive in the mail, They arrived but were very badly packaged, No anti static bag.
I installed the 8x IRF540's into the output section, Re-powerd the amplifier up only to see 3x IRF540's go up in smoke, They got super super hot really fast,(matter of seconds) I powerd the amplifer down, Removed the fried-shorted mosfets
Once i had removed the fried 'new' mosfet's, I powerd it back up again.
At this stage, It was doing simmluar to the original fault(power on-off fan at full speeed)
But now, There is 2 little RED SMD LED's right near the RCA input's that are illuminated during the on-off stage, I would assume this is due to further damage?.
At this stage, I have re-orderd 10x IRF540's from a diffrent seller, SO wile i wait for them to arrive, I thought i might see if anyone might be able to help me out, Point me in the right repair direction.
This amp is a real hard one, It's very hard to map the circuitry. I have no scematic, Can't seem to find one on this amp, So i am reapiring step by step in the dark.
Sorry for the big type up, But it's just eaisier to explain all i know
Where should i go from here?.
What are these illuminated RED SMD LED's right near the RCA input's? (on the inside of the amp, Not visable when amplifier is together)
As far as i understand, All MTX Thunder amp's have these SMD LED's in the same position.
???
Thanx all.
This may not be helpful to your cause but - where did you buy your parts from that did not package the parts correctly? This may help other DIYers.
eBaY.
Perry. Ill get that photo as soon as possible, I'll get the best pic i can.
For now, I have gone over the while board and not one burn mark anywhere, Eerything look's fine.
I spent a bit of time trying to trace the RCA sheld's back thrugh the board to see if i could find any defective part's, Found nothing. This amp is very hard to trace.
I can only assume at this stage that the red SMD LED's are a fault indicator for the RCA circut.
I'll get that photo up as soon as possible
Thanx for the reply's.
Photo's as requested
Here are the board photo's as requested.
Please let me know if you would like a more detailed photo of a particular part of the amplifier.
These are the best qualaty i can manage at this point, I only have a camera phone (8mp)
All the blue marking's on the amp are from me trying to trace the circut.
The cap that is misssing it's lid is from me, I removed it as it was bulged and wanted to see if the underside was ok.
Nothing on the board is burnt, Everything look's fine, So it make's it a little hard to find the issue.
Here are the board photo's as requested.
Please let me know if you would like a more detailed photo of a particular part of the amplifier.
These are the best qualaty i can manage at this point, I only have a camera phone (8mp)
All the blue marking's on the amp are from me trying to trace the circut.
The cap that is misssing it's lid is from me, I removed it as it was bulged and wanted to see if the underside was ok.
Nothing on the board is burnt, Everything look's fine, So it make's it a little hard to find the issue.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
This image show's the RED LED's i was talking about
Illuminated ever since new mosfet's got cooked.
(Circled in yellow.)
Illuminated ever since new mosfet's got cooked.
(Circled in yellow.)
An externally hosted image should be here but it was not working when we last tested it.
The LEDs near the RCAs on other MTX amps indicate that there is DC on the RCA shields but they also have LEDs that indicate when the rail caps are charged. I don't know what the LEDs in your amp indicate because they are near both the RCAs and the rail caps.
Why did you replace all 8 540s when only 2 were defective?
You MUST have the FETs clamped to the heatsink when you apply power to the amp. That would help protect the FETs.
Why did you replace all 8 540s when only 2 were defective?
You MUST have the FETs clamped to the heatsink when you apply power to the amp. That would help protect the FETs.
It was my understanding it's always good practise to replace all fet's from the same batch, Over just replacing some...(the blown ones)
Although, I am somewhat a newby to this.
Yes, The Red light's have me stumped.. They only came on once the new replaced 540's fried. Ever since then, They have been on...
I can only hope replacing the recently fried 540's will solve the redlight issue.
The original mica pads were in bad shape, All warped and crispy, So i just placed gaffa tape inbetween the heatsink and mosfet's during the repair stage, Just extra protection because the original pad's were almost useless and would have shorted out.
Once it's up and running, I will replace all pad's with new one's and remove the tape.. (there on order)
I really can't move forward untill the new 540's arrive.
But im just trying to get a good understanding on any other fault's before i install the new batch of 540's(don't want them to go up in smoke again) Start getting expensive...
Can anyone suggest anything that i should pay particular attention to?, Like anything that may have blown along with the output mosfet's?
The power section seem's fine, The fault's lie within the Output section, And now the RCA section.
In you're expert opinion, Should i just stick with the IRF540, Or should i try something else? Since technology has come a bit further since 2004...I think it's a 04 model..
I appreciate you all taking the time to help out.
Thanx.
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