I've been searching like crazy and have been unable to find an answer to this question.I have a 4 channel alpine with one bad channel.The complementary KTD718 and KTB688's are both done for.I have yet to find a clear answer as to what components might replace these parts?Do I simply need to find bi -polar audio output transistors with the same or higher maximum ratings?
Most of the distributors in the US are using the 2S prefix instead of the KT prefix. When you need a KTD718, search for 2SD718. The datasheet for the 2SD718 says it's an 8 amp transistor. The KEC datasheet says it's a 10 amp transistor. Otherwise, the specs are essentially the same. Generally, when I order the 2S parts, I get the KEC transistors.
Whenever you use the 2S prefix for a KEC part, you need to compare datasheets. Often, they are identical but sometimes, they are not. Sometimes, they're a completely different component.
If you want to get the original parts, order them from pacparts.com. They have one in stock but they'd have to order the other one. They are ~$11 each.
There are a couple of sellers on aBay that have the 2S versions for sale.
If the amp uses a screw to clamp the transistor (through an insulated hole in the tab), there aren't many options.
Whenever you use the 2S prefix for a KEC part, you need to compare datasheets. Often, they are identical but sometimes, they are not. Sometimes, they're a completely different component.
If you want to get the original parts, order them from pacparts.com. They have one in stock but they'd have to order the other one. They are ~$11 each.
There are a couple of sellers on aBay that have the 2S versions for sale.
If the amp uses a screw to clamp the transistor (through an insulated hole in the tab), there aren't many options.
You could also trying replacing the outputs with cross reference parts from fairchild http://www.fairchildsemi.com/crossref/crossrefSearch.do
I have an amplifier that uses the same output transistors and will be trying to replace them with parts from fairchild soon.
I have an amplifier that uses the same output transistors and will be trying to replace them with parts from fairchild soon.
Thread revival.
Have an amp here with a blown output using the KTD718 O/KTB688 O. Since these parts are hard to find and it's not worth paying a premium for them I have 3 options. I am leaning towards the 2STW4468 O/2STW1695 due to price @digikey and the value of this amp, however the FJA4313 O/FJA4313 O has a bit closer specs and more current capability.
Anyone else have any opinions before I order the 2STW4468/2STW1695?
Have an amp here with a blown output using the KTD718 O/KTB688 O. Since these parts are hard to find and it's not worth paying a premium for them I have 3 options. I am leaning towards the 2STW4468 O/2STW1695 due to price @digikey and the value of this amp, however the FJA4313 O/FJA4313 O has a bit closer specs and more current capability.
Anyone else have any opinions before I order the 2STW4468/2STW1695?
Code:
KTD718 O 2STW4468 FJA4310 O FJA4313 O
Price N/A 0.79 1.59 1.55
Source Digikey Mouser Mouser
CHARACTERISTIC SYMBOL UNIT - - - -
Collector-Base Voltage Vcb V 120 200 200 250
Collector-Emitter Voltage Vce V 120 140 140 250
Emitter-Base Voltage Veb V 5 6 6 5
Collector Current Ic A 10 10 10 17
Base Current IB A 1.0 1.5 1.5
Collector Power Dissipation Pc W 80 100 100 130
Junction Temperature Tj °C 150 150 150 150
ELECTRICAL CHARACTERISTICS (Ta=25°C)
CHARACTERISTIC SYMBOL
Collector Cut-off Current leno uA 10 0.1 10 5
Emitter Cut-off Current lEBO uA 10 0.1 10 5
C-E Breakdown Voltage Vbrceo V 120 140 140 250
DC Current Gain hfe 80-160 70-140 70-140 80-160
C-E Sat Voltage VCE(sat)V 2 0.5-0.7 0.5 0.4-3
Base-Emitter Voltage Vbe V 1.5 1.3 1.5
Transition Frequency h MHZ 12 20 30 30
Collector Output Capacitance Cob pF 170 150 250 200Pulling thread up one more time 
Quick run down:
I own a Kicker zx700.5 marine case.
Yesterday I was driving and the power to the speakers seemed to be low.
Today I decided to check my gains with my oscilloscope, as I was adjusting levels the amp started to click (relay?) and the red light would flash. Output is gone obviously.
Now, I have had that happen before when I was testing my speakers for an extended time with the car off. I simply charged the battery and everything was fine.
Today, I can't get the amp out of the flashing protect mode with the clicking of the relay I would assume :/
Done so far:
1. Tested power and ground for resistance and solid connections.
2. Measured voltage at alternator, battery, amp. Close to 14V
3. Disconnected everything and ran the amp straight to the battery with short cables. Same thing happening.
4. I noticed while the amp was clicking it was getting hot in the corner by the fuses.
Please do not tell me I have improper wiring as I have demonstrated it is not that.
Now, I have taken the top off the amp and did some testing with my dmm on some transistors.
The RL speaker pins or Q410 are reading close to 0. Q4510 is reading around 600 on my dmm. Some of the pins for other speakers are reading abnormal numbers as well.
So my question is, could these have a short circuit or blown and now causing the amp to stay in a flashing protect mode? I have already ordered 4 of each to replace the four speaker channels. Should I believe this would be the main cause, because I can't see any signs of burning or malfunctioning electronics
Thanks in advance!
Quick run down:
I own a Kicker zx700.5 marine case.
Yesterday I was driving and the power to the speakers seemed to be low.
Today I decided to check my gains with my oscilloscope, as I was adjusting levels the amp started to click (relay?) and the red light would flash. Output is gone obviously.
Now, I have had that happen before when I was testing my speakers for an extended time with the car off. I simply charged the battery and everything was fine.
Today, I can't get the amp out of the flashing protect mode with the clicking of the relay I would assume :/
Done so far:
1. Tested power and ground for resistance and solid connections.
2. Measured voltage at alternator, battery, amp. Close to 14V
3. Disconnected everything and ran the amp straight to the battery with short cables. Same thing happening.
4. I noticed while the amp was clicking it was getting hot in the corner by the fuses.
Please do not tell me I have improper wiring as I have demonstrated it is not that.
Now, I have taken the top off the amp and did some testing with my dmm on some transistors.
The RL speaker pins or Q410 are reading close to 0. Q4510 is reading around 600 on my dmm. Some of the pins for other speakers are reading abnormal numbers as well.
So my question is, could these have a short circuit or blown and now causing the amp to stay in a flashing protect mode? I have already ordered 4 of each to replace the four speaker channels. Should I believe this would be the main cause, because I can't see any signs of burning or malfunctioning electronics
Thanks in advance!
Last edited:
You should start your own thread since your amp needs repair. This thread was for general replacement devices for out dated and over priced output devices on another amp.
By the way I would say your amp is blown, most likely outputs in one or more channels, and your testing method's will finish damaging the amp if you keep powering it up with failed components inside of it. try the links below for some tech training by Perry Babin...
Try Perry Babin's Tutorial links first:
Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links
By the way I would say your amp is blown, most likely outputs in one or more channels, and your testing method's will finish damaging the amp if you keep powering it up with failed components inside of it. try the links below for some tech training by Perry Babin...
Try Perry Babin's Tutorial links first:
Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links
Hello,
Thanks for the response. I guess I should have been more clear. Those output transistors are the ones in my amp. I should have made a new post, but I figured it was a quick yes or no answer. I just wanted to know if those blew would it cause that to happen? I looked in the Kicker user manual and saw nothing about blinking red lights with proper power and ground. I'm not sure what you mean by my testing methods? In order for me to make sure it was the amp I had to test the amp alone, that was the last time I tried to power it up. Everything else was with the amp on my kitchen table with a dmm. Thanks for pointing out the links, it's where I found out where I should be looking in the first place.
Pulling thread up one more time
Quick run down:
I own a Kicker zx700.5 marine case.
Yesterday I was driving and the power to the speakers seemed to be low.
Today I decided to check my gains with my oscilloscope, as I was adjusting levels the amp started to click (relay?) and the red light would flash. Output is gone obviously.
Now, I have had that happen before when I was testing my speakers for an extended time with the car off. I simply charged the battery and everything was fine.
Today, I can't get the amp out of the flashing protect mode with the clicking of the relay I would assume :/
Done so far:
1. Tested power and ground for resistance and solid connections.
2. Measured voltage at alternator, battery, amp. Close to 14V
3. Disconnected everything and ran the amp straight to the battery with short cables. Same thing happening.
4. I noticed while the amp was clicking it was getting hot in the corner by the fuses.
Please do not tell me I have improper wiring as I have demonstrated it is not that.
Now, I have taken the top off the amp and did some testing with my dmm on some transistors.
The RL speaker pins or Q410 are reading close to 0. Q4510 is reading around 600 on my dmm. Some of the pins for other speakers are reading abnormal numbers as well.
So my question is, could these have a short circuit or blown and now causing the amp to stay in a flashing protect mode? I have already ordered 4 of each to replace the four speaker channels. Should I believe this would be the main cause, because I can't see any signs of burning or malfunctioning electronics
Thanks in advance!
If anyone was interested, I used those transistors from Fairfield. Changed them all out and amp is working flawless.
Thanks
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