My friend just gave me his old Sounstream 405s amp because it had a problem and he didn't feel like trying to fix it so he just bought a new amp. The problem is, everytime it turns on, both fuses blow instantly. I read the manual and it said if this happens, to switch it to high current mode which I did, but the same thing still happens. So I'm just wondering if anyone has had this amp with this problem or another amp with the same problem. If you did, could you give me any suggestions on how to get it working again?
-David
-David
fried amp
The output xistors are shorted / or the switching power suplply is shorted(drive transitors or dioode bridge) . This is a job for a trusty OHM meter.
Jeff
The output xistors are shorted / or the switching power suplply is shorted(drive transitors or dioode bridge) . This is a job for a trusty OHM meter.
Jeff
Thanks for the quick respone Jeff. I just have a couple of questions. First off, I'm not positive where all of those components are on the amplifier. My dad and me both have experience with electrical components, but we have never worked on a car amplifier. So if you could point out where they are in the picture, that would be very helpful. Also, is there any way to test the output resistors while they are still in the circuit?
Attachments
soundstream
Hello
The powerpsupply is on the right .the amp on the left
Do you see the white outlined little boxes? with three leads on each
those are the xistors and diode bridges. Take a ohm meter and ohm
out the leads to each other . look for ones that are completely shorted
(all 3 pins shotred to each other) let me know what you find .
jeff
Hello
The powerpsupply is on the right .the amp on the left
Do you see the white outlined little boxes? with three leads on each
those are the xistors and diode bridges. Take a ohm meter and ohm
out the leads to each other . look for ones that are completely shorted
(all 3 pins shotred to each other) let me know what you find .
jeff
I just took a ohm meter to all of the xistors and found 3 shorted ones. I am going to take the circuit board off tomorrow and run down to a parts store to see if I can find the 3 I need. The attached picture is where the short circuited ones are. 2 of them are by the high power switch.
-David
-David
Attachments
the three marked with a green thingy?
no, I don't think they are the main power mosfets. I think they are output rectifiers. as the power mosfets are beside the many filter caps.
no, I don't think they are the main power mosfets. I think they are output rectifiers. as the power mosfets are beside the many filter caps.
shorted
Before you "run " down to the parts store check each device out of circuit and confirm it is shorted take youre time when you take the board out . each device has silicone greae on it , take care not to get it all over. also double check the xistors on the left in the amp. ther should be no shorts from one pin to any other.
jeff
Before you "run " down to the parts store check each device out of circuit and confirm it is shorted take youre time when you take the board out . each device has silicone greae on it , take care not to get it all over. also double check the xistors on the left in the amp. ther should be no shorts from one pin to any other.
jeff
i have this same amp and this same problem can someone help me out on how to test these and what reading am i to get?
Check the rectifiers (D3-D8 near the power transformer) and all of the output transistors to see if any are shorted.
You should not read anything near 0 ohms between the legs of any individual transistor. You should not read anything near 0 ohms between the center leg and either out leg of any individual rectifier.
You should not read anything near 0 ohms between the legs of any individual transistor. You should not read anything near 0 ohms between the center leg and either out leg of any individual rectifier.
i understand everything except for how to test this specific mosfet/ fet due to the arrows both pointing to the right on BCAE it doesnt show how to check this particular one so if someone can give me the order this one is done in 🙂
This is a rectifier. It's generally referred to as a doubler.
R = red probe
B = black probe
meter set to diode check mode
numbers are pin numbers on rectifier 1-3 left to right
rectifier out of circuit
R1-B2 or R2-B3 > ~0.5v
R2-B1 or R3-B2 > OL
R = red probe
B = black probe
meter set to diode check mode
numbers are pin numbers on rectifier 1-3 left to right
rectifier out of circuit
R1-B2 or R2-B3 > ~0.5v
R2-B1 or R3-B2 > OL
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