Hi folks !
Sorry in adavance for my poor english...
I have a BoltAudio B3004 , im using this amp on as subwoofer for many years ( 10 years ) its probably a cheap amplifier but it been a bullet proof amp for the last 10 years , passing from a car to an other , from a subwoofer to an other without any problem whatso ever..
Ive decided to swap the amplifer and sub from a car to an other....
While im was installing the amp i broke one of the screw for the rear speaker ch . So decided to swap the sub to the front chanel instead.
I turned on the amp and started to turn up the volume.... and few secs later magic smoke appeared and the amp turn on protect mode.
After opening the amplifier and closely looking at each component ive discoverd that one of the very small transistor ( medium power transistor ( not head skinked ) as blew up resulting of very small crack on it and sticky juice.
The original transistor is a 2SD1859 medium power transistor 80V 0.7A
i took a look at the datasheet and didnt found any cross reference for it ..
So ive tryed to solder a KTC2800 that was laying around my place from an other amp..... and it didnt solve my problem. Amp still in protect mode.
I did some basic check based on the Bace1 website, made some test on few transistor and didnt found nothing apparent. ( using a fluke87)
I far for being an amp expert so im pretty new to all this stuff.. so i would like to know if someone can guide me trought this i would like to keep this amp in good shape.
thanks !
I will send picture in the next post from my cellphone.
Sorry in adavance for my poor english...
I have a BoltAudio B3004 , im using this amp on as subwoofer for many years ( 10 years ) its probably a cheap amplifier but it been a bullet proof amp for the last 10 years , passing from a car to an other , from a subwoofer to an other without any problem whatso ever..
Ive decided to swap the amplifer and sub from a car to an other....
While im was installing the amp i broke one of the screw for the rear speaker ch . So decided to swap the sub to the front chanel instead.
I turned on the amp and started to turn up the volume.... and few secs later magic smoke appeared and the amp turn on protect mode.
After opening the amplifier and closely looking at each component ive discoverd that one of the very small transistor ( medium power transistor ( not head skinked ) as blew up resulting of very small crack on it and sticky juice.
The original transistor is a 2SD1859 medium power transistor 80V 0.7A
i took a look at the datasheet and didnt found any cross reference for it ..
So ive tryed to solder a KTC2800 that was laying around my place from an other amp..... and it didnt solve my problem. Amp still in protect mode.
I did some basic check based on the Bace1 website, made some test on few transistor and didnt found nothing apparent. ( using a fluke87)
I far for being an amp expert so im pretty new to all this stuff.. so i would like to know if someone can guide me trought this i would like to keep this amp in good shape.
thanks !
I will send picture in the next post from my cellphone.
While it's good to order extra parts, I don't think that this amp will have any parallel outputs. It's a 4 channel amp with 4 groups of two output transistors.Id suggest replacing the 2n6488 that's in this channel as well.
For the drivers, I'd suggest ordering the KSA1220 and the KSC2690 for the drivers.
Most amps like this will power up if you remove the output transistors from the blown channel This will allow you to check the other channels and confirm that the power supply is functioning.
Be sure to clean up the solder pads for the transistors you remove before applying power. Clamp all remaining transistors and insert a 10 amp fuse in the B+ line to protect the remaining heatsink mounted transistors.
For the drivers, I'd suggest ordering the KSA1220 and the KSC2690 for the drivers.
Most amps like this will power up if you remove the output transistors from the blown channel This will allow you to check the other channels and confirm that the power supply is functioning.
Be sure to clean up the solder pads for the transistors you remove before applying power. Clamp all remaining transistors and insert a 10 amp fuse in the B+ line to protect the remaining heatsink mounted transistors.
That's exactly what i did, removing the suspected transistor from the board and now the amp is powering up . Ive ordered part from digykey and i found a transistor that has exactly the same specs as the 2ds1859 but surface mount instead of hole mounting type so I will solder it upside down on the other side of the board they are very small. And i bought 5 x 2n9461 too i will replace all of them and keep the old ones as backup . Wish that everything will be fine 
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