Im working on this amp. The outputs are all toasted in this.
I was looking at the outputs and there are 16 of them total.
15 of them are IRFP360LC and 1 of them is a IRFP460LC.
Are theese pretty much the same part?? Wondering if they are maybe someone fixed this amp before.
So my question is if i put all IRFP360lc's (16 of them) should i be ok?
I was looking at the outputs and there are 16 of them total.
15 of them are IRFP360LC and 1 of them is a IRFP460LC.
Are theese pretty much the same part?? Wondering if they are maybe someone fixed this amp before.
So my question is if i put all IRFP360lc's (16 of them) should i be ok?
Ahh you got a flea market repair job on your bench. I would say the 460 is not the correct part and someone did a cheapy repair before you, which most likely caused the second failure bringing the amp to your fine bench Mike.
I think the very expensive 360 is the correct part to use in this case, except now you gotta replace them all. Don't you just love those cheap fast repair tech's out there. makes me want to buy a firearm...
I think the very expensive 360 is the correct part to use in this case, except now you gotta replace them all. Don't you just love those cheap fast repair tech's out there. makes me want to buy a firearm...
The difference between the 360 & 460 is the voltage rating (360 is a 400V Mosfet & 460 is 500V rating), there will be a slight difference in drain source on resistance which will cause the other IRFP360s to possibly carry a tad more current than the 460. I wouldn't expect the whole thing to blow though just because one mosfet happens to be carrying a bit less current than 7 (or 3 if a stereo amp) others
As you are talking about an amplifier output stage switching times simply don't matter as the mosfets will be driven linear from a voltage source.
I guess it's possible that one mosfet out of spec could cause the demise of the others, however i'd describe the amp as miles too close to the edge if this was true
Blowing mosfets in a stable circuit isn't easy if it's designed right & the load is in spec, i'd look at what it was driving. Killing all the fets aint easy & indicates a pretty catastrophic failure. Something tells me there is more to this than just the mosfet/s
As you are talking about an amplifier output stage switching times simply don't matter as the mosfets will be driven linear from a voltage source.
I guess it's possible that one mosfet out of spec could cause the demise of the others, however i'd describe the amp as miles too close to the edge if this was true
Blowing mosfets in a stable circuit isn't easy if it's designed right & the load is in spec, i'd look at what it was driving. Killing all the fets aint easy & indicates a pretty catastrophic failure. Something tells me there is more to this than just the mosfet/s
Mike, I'd suggest that you pass on this repair unless you have 'deep pockets'. These amps can be very difficult to repair and one mistake can lead to the failure of all of the outputs.
If the outputs aren't soldered in place perfectly, the spring clamps may not apply enough force to get the transistors to lay perfectly flat against the sink and the amp will fail the first or second time the amp is driven to full power (at which point, the owner will expect you to repair it again for free.
If the outputs failed, you'll have to replace the driver ICs on the audio driver board.
Did it feel like any of the legs on the power supply FETs were weak when you pulled them away from the heatsink?
If the outputs aren't soldered in place perfectly, the spring clamps may not apply enough force to get the transistors to lay perfectly flat against the sink and the amp will fail the first or second time the amp is driven to full power (at which point, the owner will expect you to repair it again for free.
If the outputs failed, you'll have to replace the driver ICs on the audio driver board.
Did it feel like any of the legs on the power supply FETs were weak when you pulled them away from the heatsink?
It didnt feel like any power supply fets were loose however all of the outputs (16) are toasted it blew the fronts off them
Also noticed shaddy solder connections on all outputs and some power supply fets.
1MOREAMP,
Yes it does make me wanna get a gun sometimes I talked to the guy who owns this amp and he said he had it repaired before and it lasted a week.
Perry,
Ive alreadt ripped into this amp so im gonna have to put it back together
I ordered all new outputs ($5.17 each) And you said i have to replace the IC'S also?
Also noticed shaddy solder connections on all outputs and some power supply fets.
1MOREAMP,
Yes it does make me wanna get a gun sometimes I talked to the guy who owns this amp and he said he had it repaired before and it lasted a week.
Perry,
Ive alreadt ripped into this amp so im gonna have to put it back together
I ordered all new outputs ($5.17 each) And you said i have to replace the IC'S also?
Perry,
I Talked with someone else about this amp and he said the same thing as you did.
Told me not to mess with the amp .
He said that when maxxsonics designed this amp they did a crap job of designing this amp and i can replace all of the outputs all the power supply fets and put a new output driver board in this amp. And as soon as i hook it up all of my work can go down the drain in 2 secs.
He said they use to long of traces to the gates and the amp has problems with cross conduction.
So im wondering if i should even mess with this or put it back together and tell the guy it cant be fixed.
Any suggestions for me i know you told me not to mess with it should i stick to what you have told me and not attempt to do it?
I Talked with someone else about this amp and he said the same thing as you did.
Told me not to mess with the amp .
He said that when maxxsonics designed this amp they did a crap job of designing this amp and i can replace all of the outputs all the power supply fets and put a new output driver board in this amp. And as soon as i hook it up all of my work can go down the drain in 2 secs.
He said they use to long of traces to the gates and the amp has problems with cross conduction.
So im wondering if i should even mess with this or put it back together and tell the guy it cant be fixed.
Any suggestions for me i know you told me not to mess with it should i stick to what you have told me and not attempt to do it?
Sometimes, the repairs go well and you find all of the problems the first time through. Other amps can fail repeatedly before you find the problem. I've seen things like intermittently shorted inductors that took quite a bit of force (twisting/pushing on the inductor) to find the defective inductor. This type of problem can cause the amp to fail repeatedly. This isn't like the BD1500 that had relatively inexpensive parts that could be replaced in less than an hour. When this amp goes down, it's expensive and very time consuming. If you want to attempt it, we'll try to help you through it but I'd avoid it. I refuse to repair any of this type of amp that has the vertically orientated transistors.
Even if you repair it properly, it's not likely to be reliable long term because of the poor mechanical design that tends to break legs off of the FETs.
If you decide to repair it, give an estimate that will cover 3x the cost of ALL of the FETs plus what it's worth for 8 hours of labor (minimum).
I'd recommend that you tell him to send it to dB-r or back to the manufacturer.
Even if you repair it properly, it's not likely to be reliable long term because of the poor mechanical design that tends to break legs off of the FETs.
If you decide to repair it, give an estimate that will cover 3x the cost of ALL of the FETs plus what it's worth for 8 hours of labor (minimum).
I'd recommend that you tell him to send it to dB-r or back to the manufacturer.
Ok ill see what he wants to do. I told him I wont warranty my work on the amp. I also told him just for parts it would be $300.00 to $350.00 .
And i told him for labor it would be probably be $200.00 That only $25.00 an hour to fix this thing .
So ill see what he wants to do in the next few days.
Ill post back when i find out what he wants to do.
But he wants to run this amp in competiton's so I kinda wanna steer away from the repair. But i guess well see
And i told him for labor it would be probably be $200.00 That only $25.00 an hour to fix this thing .
So ill see what he wants to do in the next few days.
Ill post back when i find out what he wants to do.
But he wants to run this amp in competiton's so I kinda wanna steer away from the repair. But i guess well see
I don't know precisely how you told him that you wouldn't warranty your work. You have to be careful that he doesn't tell everyone that you don't warranty any of your work. In the future, you should tell them, prior to doing any work, that you don't really want to do the repair on this type of amp (really large, poorly designed, time consuming...) but if they have few/no other options, you'll show them that it works when they pick it up.
Explain to them that due to the poor quality of the design, that's prone to failure when used as it's designed, there's no way to provide a warranty as you would on other amps. When they pick it up, play it for as long as they want so they see it's working properly. Explain to them that it's up to them to have it properly installed and if it fails again, they will have to pay for the repair again (parts and labor). Tell them this at least twice and confirm that they understand it. You can't allow them to make 'their' problem 'your' problem.
On 'normal' amps, you should offer a warranty because there's a decent profit margin but on these, you have to handle it differently.
Explain to them that due to the poor quality of the design, that's prone to failure when used as it's designed, there's no way to provide a warranty as you would on other amps. When they pick it up, play it for as long as they want so they see it's working properly. Explain to them that it's up to them to have it properly installed and if it fails again, they will have to pay for the repair again (parts and labor). Tell them this at least twice and confirm that they understand it. You can't allow them to make 'their' problem 'your' problem.
On 'normal' amps, you should offer a warranty because there's a decent profit margin but on these, you have to handle it differently.
If you do repair the amp, you may be able to seat the transistors better by touching the bottoms of the legs one at a time after the clamps are back on... to relieve some of their tension. This is of course if there is enough room to get your iron to the spots where they are soldered into the board without destroying anything nearby.
/\Ok nevermind, scratch that. I just checked some pics of random hifonics goliath models and the clamps cover the legs pretty well. By the way, which goliath model is it?
/\Ok nevermind, scratch that. I just checked some pics of random hifonics goliath models and the clamps cover the legs pretty well. By the way, which goliath model is it?
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.