After further investigation, I was able to determine that the IRF3205's will work as is, and will not cause the amp to fail.
yes both are operational, we went through the entire remote curcuit.
Replaced the 4R7 Resistor
Replaced the 0--ohm resistor RP87
Repaired a burnt out trace on the bottom of the board
Replaced 2SB772 (On daughter card was shorted)
Replaced Q3 2N4403
Replaced TL494C after confirming it was failed. Once i had the daughter cards working i still did not have drive present at the power suppy gate resistors.
Replaced the 4 IRFP46Z (I used IRFP3205 in place of the originals, only beacuse original transitors i did not have in stock)
Back to operational state.
Replaced the 4R7 Resistor
Replaced the 0--ohm resistor RP87
Repaired a burnt out trace on the bottom of the board
Replaced 2SB772 (On daughter card was shorted)
Replaced Q3 2N4403
Replaced TL494C after confirming it was failed. Once i had the daughter cards working i still did not have drive present at the power suppy gate resistors.
Replaced the 4 IRFP46Z (I used IRFP3205 in place of the originals, only beacuse original transitors i did not have in stock)
Back to operational state.
Still, however drawing 1.28Amps of current and slowely rises the longer i leave the amplifier powered up, There is audio present but its missing one of the output transistors from curcuit i took it from this amplifier to repair one and never repalced it, unsure of what the part number is. 
Thnaks to papaBIllZ for this and all my kicker repairs.
Thnaks to papaBIllZ for this and all my kicker repairs.
Still, however drawing 1.28Amps of current and slowely rises the longer i leave the amplifier powered up, There is audio present but its missing one of the output transistors from curcuit i took it from this amplifier to repair one and never repalced it, unsure of what the part number is.
The outputs Transistors are 2SD718 and 2SB688. Are you still missing one of the output transistors?
Is the amp board clamped down in the chassis when you observe the slow rise in current draw? 1.28 amps is normal idle current. If the amp is not clamped down its possible an output is drawing excessive bias current which will cause the power supply mosfet/s to draw more current and thermal runaway, will cause the current to rise. If you let it, it will short the output transistor and a power supply mosfet or two.
If everything is in place and clamped down in the chassis and the amp is exhibiting the slow rise, there may be an issue with the bias circuit in one channel.Check to see if you have and DC voltages on any the speaker terminals. If you can apply a 1Khz test tone look to see if you have clean output on the speaker terminals.
Last edited:
Yes I replaced the missing outputs. But I had not clamped the amplifier down yet. So it was a slow rise of current as the power supply mosfets heated, they dissipated more wattage and cause more current draw. Clamped the Amplifier displays a perfect 1khrtz sine wave in all four outputs.
Repaired.
Repaired.
Did you replace both Q203-D718 and Q209-B688? Lift R34-10kΩ, this disables protection for Amp 2. Careful when applying power, so that there is not excessive current draw. I don't think there will be and the amp will power up normally, with no output on Amp 2 and all other Amps/Channels normal.
If this is the case replace Q201,210-MPSA06 and Q210-MPSA56. Quite often if an output shorts, it will take out one or more transistors in the preceding driver stages. Q204-MPSA06 sets up the bias for this Amp.
If this is the case replace Q201,210-MPSA06 and Q210-MPSA56. Quite often if an output shorts, it will take out one or more transistors in the preceding driver stages. Q204-MPSA06 sets up the bias for this Amp.
Okay, It's possible there is another bad channel. Lift R88 (Amp3) R89 (Amp4) one at a time to see if either one brings the amp out of protection.
There is also a DC Protection sense resistor for each channel. If none of the Protection sense resistors fails to bring the amp out of protection lift R108(Amp1), R83(Amp2), R308(Amp3),R408(Amp4), again one at a time. All of these resistors are 10KΩ according to my schematics. Your post #34 states 1KΩ, are you sure that is correct?
There is also a DC Protection sense resistor for each channel. If none of the Protection sense resistors fails to bring the amp out of protection lift R108(Amp1), R83(Amp2), R308(Amp3),R408(Amp4), again one at a time. All of these resistors are 10KΩ according to my schematics. Your post #34 states 1KΩ, are you sure that is correct?
R83 finally did the trick. You are correct 10k it was my mistake. So now that the amplifier comes out of protection. It does not draw any current, with it lifted. I fiqured it was amp 2. It was the damaged channel and without the output transistors in circuit, the amplifier powered up. If i attempt to seat r83 at anytime amplifier goes straight back mb into protection. The channel has audio
Yes, only if i lift r83 does it come out of protection. Amp2 right channel has clear audio. Amp2 left has light scatchy audio and amp 1 nothing, audible pop when touching the channel. Ill check for dc at the speaker terminal.
None of the outputs are reading a short on curcuit, but i started pulling them anyway to test them, or replace them if need be.
None of the outputs are reading a short on curcuit, but i started pulling them anyway to test them, or replace them if need be.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.