Let me start off by saying my electronics repair experience is very limited. I don't have an oscilloscope that works (long story), so I'm only able to do simple diag with a DMM.
I have a Sundown SIA-2500D. Recently, one of the power supply mosfets (IRF-1404) blew up. Gate resistors measured okay, checked gate to source on all fets and they don't appear to be shorted. Visually everything else is okay. I replaced the blown one with a new one, gave power to the board, and it immediately blew a chunk right off the top of the package. I thought I would try replacing it one more time just in case it was a bad fet, and it popped again. I'm going to mess around with it a bit more to see if there's anything I can do, if not, I'll hand it over to a professional to take care of. I would appreciate any help in diagnosing.
I have a Sundown SIA-2500D. Recently, one of the power supply mosfets (IRF-1404) blew up. Gate resistors measured okay, checked gate to source on all fets and they don't appear to be shorted. Visually everything else is okay. I replaced the blown one with a new one, gave power to the board, and it immediately blew a chunk right off the top of the package. I thought I would try replacing it one more time just in case it was a bad fet, and it popped again. I'm going to mess around with it a bit more to see if there's anything I can do, if not, I'll hand it over to a professional to take care of. I would appreciate any help in diagnosing.
The first thing to do is find out why it blew in the first place. A schematic would help.
Common causes are; Failing to switch off fast enough, Snubber circuit defective, Mark Space ration incorrect, Serious overload etc etc etc.
When you have found out the cause, then replace the MosFet with a genuine one, not eBay or Amazon etc. Mouser or Element 14 are a known reliable source for components depending on your part of the world and availability.
Common causes are; Failing to switch off fast enough, Snubber circuit defective, Mark Space ration incorrect, Serious overload etc etc etc.
When you have found out the cause, then replace the MosFet with a genuine one, not eBay or Amazon etc. Mouser or Element 14 are a known reliable source for components depending on your part of the world and availability.
I can't get the schematics. Sundown support says their one certified repair shop has them. I asked that repair shop, and they can't share them due to an NDA. Stupid. Can't find them anywhere online
I used some eBay parts from germany. they claim they're international rectifier, but they might be knock offs.
I used some eBay parts from germany. they claim they're international rectifier, but they might be knock offs.
So I come back with some more information. I replaced a 4.7 ohm resistor near the gate driver that read out of spec (measured 90 ohm), replaced 4 gate resistors, and 4 mosfets as they tested bad. I also replaced the mosfet hi/lo gate driver because they were cheap and it seemed to be a good idea, and I didn't have an oscilloscope to test if it was switching. I replaced these with genuine components from Mouser.
This time, I powered the amp with a power supply limited to 3 amps. Immediately upon doing so, I hear what sounds like a squeaking sound, roughly every second or two. Sounds like it might be coming from the transformer? I see a very slight whisp of smoke coming from the gate driver I had just replaced. I'm looking for some guidance on where to go from here.
This time, I powered the amp with a power supply limited to 3 amps. Immediately upon doing so, I hear what sounds like a squeaking sound, roughly every second or two. Sounds like it might be coming from the transformer? I see a very slight whisp of smoke coming from the gate driver I had just replaced. I'm looking for some guidance on where to go from here.
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eBay?? Yes, nearly always fakes these days, eBay/Amazon are not the places to go for semiconductors.
Okay, so I replaced 4 mosfets, their respective gate resistors, the hi/lo gate driver, and this one resistor near the gate driver that was visually damaged and read out of spec. These were replaced with genuine parts from Mouser. I got the amp working, I had it playing at a low level, and I slowly started cranking up the gain to my appropriate level, and as I was bumping it up a step, the clip light comes on and the amp dies. Upon disassembling, I find that one mosfet blew again, took out some gate resistors, likely the other mosfets as well (have yet to test), and that one resistor near the hi/lo side driver measures out of spec again.. I'm not sure what could cause it to play for a bit and then blow up again when I increase the power. there were no obvious shorts, I used appropriate amount of thermal compound, I'm just not sure what could have went wrong this time.
Hi,
Unless you purchase from reputable suppliers such as Mouser, then you may be wasting your time implementing components from ebay etc.
If the amplifier is clipping, i am assuming that this means over current drive ?
Does this then mean your load is below specification of the amplifier ?
Looking at the amplifier from searching the internet, Amazon prices it at £373, and states it is a 2.5kW RMS monoblock. If the maximum voltage is 16volts, it implies 156amps RMS current output (approx 0.1ohm load impedance).
Since you have tried to repair a few times, and the amplifier has failed, then it may be cheaper in the long term to get it repaired by someone with the relevant circuit diagrams to fault find accurately, or purchase another amplifier ?
Regards,
Shadders.
Unless you purchase from reputable suppliers such as Mouser, then you may be wasting your time implementing components from ebay etc.
If the amplifier is clipping, i am assuming that this means over current drive ?
Does this then mean your load is below specification of the amplifier ?
Looking at the amplifier from searching the internet, Amazon prices it at £373, and states it is a 2.5kW RMS monoblock. If the maximum voltage is 16volts, it implies 156amps RMS current output (approx 0.1ohm load impedance).
Since you have tried to repair a few times, and the amplifier has failed, then it may be cheaper in the long term to get it repaired by someone with the relevant circuit diagrams to fault find accurately, or purchase another amplifier ?
Regards,
Shadders.