my question mr perry, i have an amplifier http://ampguts.realmofexcursion.com/Pioneer_PRS-D5000SPL/inside1.jpg
im having an overheating problem on the output fets, what i noticed is that the output frequency capacitor (final cap across the speaker out terminals (big brown cap)), there is an arrangement with (leading from the speaker positive out) two 2.2ohms resistors in series to negative leg of a bipolar condenser coupling with another bipolar condenser positive leg then in-turn pin to the negative of the speaker output, i figured two condensers coupling that way is representing a non-polarised condenser, am i right? my issue is when one of that resistor is open the amp overheats even with no load or signal, ive replace one of the original but the problem occurrs on the other resistor, so i want to know what is the caused, or if i put another 2.2ohms what damages may i expect?
im having an overheating problem on the output fets, what i noticed is that the output frequency capacitor (final cap across the speaker out terminals (big brown cap)), there is an arrangement with (leading from the speaker positive out) two 2.2ohms resistors in series to negative leg of a bipolar condenser coupling with another bipolar condenser positive leg then in-turn pin to the negative of the speaker output, i figured two condensers coupling that way is representing a non-polarised condenser, am i right? my issue is when one of that resistor is open the amp overheats even with no load or signal, ive replace one of the original but the problem occurrs on the other resistor, so i want to know what is the caused, or if i put another 2.2ohms what damages may i expect?
Prsd-5000spl
ive markered the area on the amplifier, i will try to post a close up of the actual area so you can see the line up, as i said before once you replace the resistor it runs cool but i dont know why it blows the first time, so i only change one, but i dont know what gonna happen when i change the next one.
is there voltage come thru the output? do i need to adjust the biasing preset control?
ive markered the area on the amplifier, i will try to post a close up of the actual area so you can see the line up, as i said before once you replace the resistor it runs cool but i dont know why it blows the first time, so i only change one, but i dont know what gonna happen when i change the next one.
is there voltage come thru the output? do i need to adjust the biasing preset control?
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lumanauw:
Thanks for moving the posts.
Formas:
In the future, please start new threads when you need help.
Yes, the two reverse connected capacitors are used in place of a non-polarized capacitor.
Confirm that the two capacitors are not shorted (confirm that they're within tolerance if possible). Reinstall the caps and two new 2.2 ohm resistors. If the resistors overheat, check the 3300uf@100v capacitor. If it's within tolerance, the inductor L301 may be shorted.
Thanks for moving the posts.
Formas:
In the future, please start new threads when you need help.
Yes, the two reverse connected capacitors are used in place of a non-polarized capacitor.
Confirm that the two capacitors are not shorted (confirm that they're within tolerance if possible). Reinstall the caps and two new 2.2 ohm resistors. If the resistors overheat, check the 3300uf@100v capacitor. If it's within tolerance, the inductor L301 may be shorted.
now tell me mr Perry, ive used a capanalyzer and check and one of the cap was faulty thats a 100v/44uf, what does that little circutry of low ohms resistor and cap arrangement does, cause as i say the amp still plays but a massive heat is building on the output fets..????
what i would love to know is what does the output coil, the puff capacitor and the little assorted circuitry does in that output stage, and relate why the feedback for me.
what i would love to know is what does the output coil, the puff capacitor and the little assorted circuitry does in that output stage, and relate why the feedback for me.
I'm not sure what purpose those components serve. There is another larger capacitor across the outputs that should filter the remaining carrier from the output. These possibly present a light load to the amplifier in case there are no speakers attached to the speaker terminals. It may be unstable with no load. Maybe someone else can provide a more definitive answer from the attached image.
Attachments
Useful info on Zobel network in class D amplifiers from this forum.
http://www.diyaudio.com/forums/showthread.php?t=145352&highlight=zobel
http://www.diyaudio.com/forums/showthread.php?t=145352&highlight=zobel
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