- Thread Starter
- #16
I have 4 years electronics training. As far as the amp i chose to replace the mosfets with IRF740 there 400v 10 amp fets. There is no schematic and no datasheets on the original part.
Which mosfets? What kind of amp? What location in the amp? You should snap a few pics and show us what you are talking about. If those FET's you replaced are power supply fets I would not expect the amp to last long if it even works. 10 amp FET's are not going to cut it in the power supply or even in the output section in some cases. It's also not as easy as just replacing the burnt parts. There are other parts of the circuit you need to look into before you call it good. I do have experience with this which is why I question the parts. Never seen or heard of this part being used as a power fet in any amp. Let me help ya out a bit. If you have the wrong parts in the amp and you fire it up there is a chance you could have a catastrophic failure and make the amplifier completely unrepairable.
- Thread Starter
- #18
Its a soundstream TRX1000D. Power supply section of the board, I cant show you pics dont have a digi camera. They are power mosfets and common in amps. What mosfets do you recommend? There are other mosfets that are 20 amp and cost 6 dollars a piece. I did checks on other sections of the board and it looks good.There are 10 mosfet transistors. http://audiolabga.com/data_html/IRF.html
Last edited by a moderator:
I know Perry, I've spoken with him via email in the past, he's a nice guy and very knowledgable. I bought his amplifier repair tutorial and it taught me quite a bit. I wish I had more time and the equipment to work on amplifiers. I did some work on the first blown Crunch GP3k I had when I was still at my internship because I had access to any piece of electronics equipment you could imagine but I don't work there anymore and school has got me crazy busy. I'd love to get back into it some day though. That's pretty impressive that you don't have any formal education in the field but know enough to be able to repair amplifiers, not many here have that level of knowledge.
Last edited by a moderator:
I've always been more of a hands on person. I've done a lot of the math and crazy calculations that go along with electronics and read text books until my eyes bled but I learned more about amp repair by just getting in there and working on one than I ever learned in electronics courses. Perry has always been extremely helpful as well.
sorry for the threadjack OP. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif
Yeah I know what you mean, a lot of the crap they force me to learn seems very unnecessary but it's not really what you know that gets a good job it's what a little piece of paper says you know. I had an internship for 2 years at a large glass company doing electrical work everyday and the majority of things I needed to know for that job were learned on-site.
I still didn't see the irf746n. I see 740's . Is that what you got ? Can't say I've ever seen an amp use 10 amp fets in the power supply even cheap ones. How many total does the amp take. Usually the fets would be rated for at least 40- 50 amps in the power supply. If the parts in your amp are to-220 casing and in the power supply I would be fairly sure they are supposed to be IRFZ46N.
Just re-read this. You can't find a data sheet on the original part because you are looking for the wrong part number. Does your amps circuit board look similar to the one in this link: Power Acoustik A1800DB - Car Audio Classifieds
If it does look like that then you need to get IRFZ46N . Electronic Components from the Best - Future Electronics has them for under a dollar a piece. Make sure you check the gate resistors as well. If you have an oscilloscope check the gate drive signal on the gates to make sure it looks ok. With 10 amp fets in your amp it will not last long. If you have ten ps fets you only have 100 amps of power supply for an amp that is going to draw over 100 amps. They will be running at or near capacity most of the time. They won't last.
- Thread Starter
- #26
Well its a full bridge class d amplifier and the rail voltage can be well over 100v. iRFz46n wont work in this case. The transformer is huge.
A 1000 watt rms amp will not have 100 volt rails.The rail voltage is on the other side of the transformer from the power supply fets anyways. The fets in the power supply don't need to handle anywhere near 100 volts. Possibly the output fets would need a 100 volt rating but not in your amp. I have an earthquake D2 here(2000 watts rms) that only has 55 volt rated fets in the power supply. In addition this amp does roughly twice the power of yours and the rails are still only 80 volts. You do not need a 400 volt rated part in the power supply. It's your amp so you can put whatever you want in there but I wouldn't expect it to last long if at all with the IRF740 in there. It doesn't handle enough current for this application. It may work for a bit but you will end up having to replace the PS fets again. Best of luck on this repair.
Activity
No one is currently typing a reply...
About this thread
