I bought my Alpine MRP-M100 a few months ago, and its worked great until a few days ago.. I was playing music at normal listening levels (no where close to clipping). Amp wasn't getting any warmer than usual. The it just all together stopped playing. I pulled over to check it out. The light was still on, And the sound from the sub (Alpine Type-R 15 Dual 4ohm coils (2ohms at the amp)) sounded similar to coil rub. It was very quiet scratchy sound. The checked out all good.
Checked the voltage at the amp, Everything was good.
Removed the amp and took the back plate off, Everything inside looked good and tight. Only thing out of the ordinary was the leads on one transistor. they looked a little golden (as if they got a little warm).
I was referred here by "I am an Idiot"
Checked the voltage at the amp, Everything was good.
Removed the amp and took the back plate off, Everything inside looked good and tight. Only thing out of the ordinary was the leads on one transistor. they looked a little golden (as if they got a little warm).
I was referred here by "I am an Idiot"
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Can you take a picture of the inside of the amp and post them here?
Perry, do you have picures?
First thing we need to do is make sure the power supply of the amp is working properly, Can you locate the Rectifier diodes? Probably a 3 legged device that looks like a transistor. They will be mounted to the heat sink. THey wil be connected directly to the secondary windings of the transformer. If you can locate them, power the amp up and check voltage from center leg of one device to the center leg of the other one. You are looking for DC voltage.
Perry, do you have picures?
First thing we need to do is make sure the power supply of the amp is working properly, Can you locate the Rectifier diodes? Probably a 3 legged device that looks like a transistor. They will be mounted to the heat sink. THey wil be connected directly to the secondary windings of the transformer. If you can locate them, power the amp up and check voltage from center leg of one device to the center leg of the other one. You are looking for DC voltage.
Same problem...
I have the same problem with my amp... the light is on, but there is no sound comming to the speakers... first time it happened i sent it to a shop - they said that 4 MOSFETS were dead... the ones on the right side next to the RCA Jack. After a month or so they were dead again.... then I changed them, and while trying the amp without being mounted on the heatsink, it worked for 3-4 sec and then i think the small 3 transistors blown - the KTD600K and KTB631K.... now i'm looking for a shop where i can buy them, but its pretty hard though.... its like they aren't sold anywhere! Also I need them shipped to Germany which makes it even harder... Do someone knows such a shop or maybe other transistors that would substitute these??
Thank you very much...
I have the same problem with my amp... the light is on, but there is no sound comming to the speakers... first time it happened i sent it to a shop - they said that 4 MOSFETS were dead... the ones on the right side next to the RCA Jack. After a month or so they were dead again.... then I changed them, and while trying the amp without being mounted on the heatsink, it worked for 3-4 sec and then i think the small 3 transistors blown - the KTD600K and KTB631K.... now i'm looking for a shop where i can buy them, but its pretty hard though.... its like they aren't sold anywhere! Also I need them shipped to Germany which makes it even harder... Do someone knows such a shop or maybe other transistors that would substitute these??
Thank you very much...
The following 'may' work but in class D amps it's difficult to know if substitute parts will work properly until you try them.
http://datasheet.octopart.com/KSA1220AYSTSTU-Fairchild-datasheet-83996.pdf
http://datasheet.octopart.com/KSC2690AYSTU-Fairchild-datasheet-33981.pdf
You should always have the power semiconductors clamped tightly to the heatsink when power is applied unless you're troubleshooting and need to access components that are not accessible when the power semis are clamped down. When they're off of the heatsink, they can overheat and fail within seconds, even if there is nothing wrong with the amp.
http://datasheet.octopart.com/KSA1220AYSTSTU-Fairchild-datasheet-83996.pdf
http://datasheet.octopart.com/KSC2690AYSTU-Fairchild-datasheet-33981.pdf
You should always have the power semiconductors clamped tightly to the heatsink when power is applied unless you're troubleshooting and need to access components that are not accessible when the power semis are clamped down. When they're off of the heatsink, they can overheat and fail within seconds, even if there is nothing wrong with the amp.
Tried substitution
Hey, thank you for the fast reply!
As I couldn't find a shop where to buy the substitution transistors you said, I found in Germany where i'm living another one, that I thought must work.
2SD600K and 2SB631K ... As i can see in the Datasheets, they must be the same as the ones from KEC Corp KTD600K and KTB631K ... I have waited 8 days for them to arrive, and have puted them on the board today, but with no success... After I put the + and - to the amp, the blue light indicating that he should be on, starts flickering at a rate of 1 flick per second, and as I'm supplying the electricity for the amp from a Battery Charger, on every flick, the charger shows a big amount of energy drain, even though there is no music played to the input... can it be the Charger the problem? because he only supplies 10A? Or is it because its a Class-D amp and he does take no substituted parts? The test was done with everything mounted on the heatsink this time!
Thank you!
Hey, thank you for the fast reply!
As I couldn't find a shop where to buy the substitution transistors you said, I found in Germany where i'm living another one, that I thought must work.
2SD600K and 2SB631K ... As i can see in the Datasheets, they must be the same as the ones from KEC Corp KTD600K and KTB631K ... I have waited 8 days for them to arrive, and have puted them on the board today, but with no success... After I put the + and - to the amp, the blue light indicating that he should be on, starts flickering at a rate of 1 flick per second, and as I'm supplying the electricity for the amp from a Battery Charger, on every flick, the charger shows a big amount of energy drain, even though there is no music played to the input... can it be the Charger the problem? because he only supplies 10A? Or is it because its a Class-D amp and he does take no substituted parts? The test was done with everything mounted on the heatsink this time!
Thank you!
I measured the resistance on every of the Mosfets, not just on the 8 IRF3415... the other group consists of 8 IRF3205.
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On the first group of IRF3415 (top right) I get no reading at all
On the second one (bottom right) I get a reading just on 2 mosfets(first from right to left, and third from right to left), and thats about 103 ohms or so between gate and source.
On the two big ones mounted onto the heatsink(C25P20FR and KCF25A20) I get a 1.5ohm reading on every single leg combination, which should be an actuall 0 ohm, because when I touch the meter negative to the meter positive, I also get a 1.5ohm...
On the first group of IRF3205(top left) I get one 1.5ohm(0 ohm) reading between the drain and the source and thats on the arrowed mosfet ... the same on the group below - on the arrowed mosfet between drain and source a 1.5ohm reading... on the others I get some readings but nothing closer to 0...
On the new transistors - the 2SD600K I get nothing closer to 0, but on the 2SB631K I get a 2.8 ohm reading(when still meter positive to negative gives 1.6ohms) and thats between drain and source.
All of the test are made with everything mounted on the board.
This draining everysecond seems just like a short circuit being made every second once... I can't explain to myself what can be the reason when the substituted transistors have exactly the same characteristics as the original ones...
Thanks for your help again!
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On the first group of IRF3415 (top right) I get no reading at all
On the second one (bottom right) I get a reading just on 2 mosfets(first from right to left, and third from right to left), and thats about 103 ohms or so between gate and source.
On the two big ones mounted onto the heatsink(C25P20FR and KCF25A20) I get a 1.5ohm reading on every single leg combination, which should be an actuall 0 ohm, because when I touch the meter negative to the meter positive, I also get a 1.5ohm...
On the first group of IRF3205(top left) I get one 1.5ohm(0 ohm) reading between the drain and the source and thats on the arrowed mosfet ... the same on the group below - on the arrowed mosfet between drain and source a 1.5ohm reading... on the others I get some readings but nothing closer to 0...
On the new transistors - the 2SD600K I get nothing closer to 0, but on the 2SB631K I get a 2.8 ohm reading(when still meter positive to negative gives 1.6ohms) and thats between drain and source.
All of the test are made with everything mounted on the board.
This draining everysecond seems just like a short circuit being made every second once... I can't explain to myself what can be the reason when the substituted transistors have exactly the same characteristics as the original ones...
Thanks for your help again!
I don't think the replacement transistors are causing the problem.
On the rectifiers (the 'big ones'), if you measure from the center to the outer legs and leave the meter on it for a few seconds, does it change from 1.5 ohms?
Remove the two FETs reading 103 ohms and check them off of the board.
For the 1.5 ohms on the 3205s... if there was a short between those two legs, the amp would draw excessive current without remote voltage applied. Does this amp draw excessive current without remote voltage applied?
On the rectifiers (the 'big ones'), if you measure from the center to the outer legs and leave the meter on it for a few seconds, does it change from 1.5 ohms?
Remove the two FETs reading 103 ohms and check them off of the board.
For the 1.5 ohms on the 3205s... if there was a short between those two legs, the amp would draw excessive current without remote voltage applied. Does this amp draw excessive current without remote voltage applied?
All of the 8 IRF3415 have been replaced with brand new ones... I have done that actually before something went wrong with the small 3 transistors.
On the rectifiers, when I meassure from the center to the outer legs and leave it for a few seconds, it stays on 1.5 ohms... it doesn't change..
When I remove the remote and apply the voltage no excessive current is being drawn as far as I can see on the battery charger... After that, I put the remote back on, the amp lights for 1.5 seconds and then starts draining excessive current as being shorted every second once... the light starts flickering with every of this drains...
Before I tried these transistors as a replacement, I remember that I have read in a german forum - some BD238, that as I see doesn't have anything to do with the originals..... I replaced one of the D600K(the left one) and started the amp - he started flickering in the same manor... then I took the replaced one off the board and ran the amp - he wasn't flickering anymore... even though there was no transisotr on the left side...then I replaced the right one and the same thing happend...
On the rectifiers, when I meassure from the center to the outer legs and leave it for a few seconds, it stays on 1.5 ohms... it doesn't change..
When I remove the remote and apply the voltage no excessive current is being drawn as far as I can see on the battery charger... After that, I put the remote back on, the amp lights for 1.5 seconds and then starts draining excessive current as being shorted every second once... the light starts flickering with every of this drains...
Before I tried these transistors as a replacement, I remember that I have read in a german forum - some BD238, that as I see doesn't have anything to do with the originals..... I replaced one of the D600K(the left one) and started the amp - he started flickering in the same manor... then I took the replaced one off the board and ran the amp - he wasn't flickering anymore... even though there was no transisotr on the left side...then I replaced the right one and the same thing happend...
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