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Hartke b120 bass amp....not stable blows new output transistors and drivers ...what do you think ?

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5 Suggested Answers

SOURCE: amp blows fuses

The fuses are there to protect the internals of the AMP.....
Please check that the correct fuses are installed......
if the incorrect ones are installed then a fire may develope...

There should be a manufacturers lable on the external chassis that details the fuses to use....

Fuses now days can be slow blow or fast blow....so the correct fuses must be used.....dont increase the fuse rating past the chassis panel label...but make sure they are correct...if they are correct then the amp needs a service to determine where the peak loadings to the power supply are originating from...

Some one may have installed incorrect fuses in the past...

Cheers from YUBEUT


Posted on Nov 03, 2007

  • 2 Answers

SOURCE: amp : sansui au11000 blown transistors on driver board

Sometimes just replacing the outputs that have shorted are not enough to complete the repair of a main amp...this is because sometimes there is an intermittant or full failure in the bias circuit. Typically the Bias POT is the culpret.....when these pots get dirty or fail, the bias current ramps up way too high and then the Output transistors blow.......always replace the POT as part of the repair.....also check the bias varistor (Diode Stack) as these can open up after the first failure. Always pay attention to the bias circuit as this is critical to completing the repair properly....bias current adjustments can be made by measuring the voltage accross the Emitter Resitors connected to the Power Transistors...should read about 10 millivolts. The MJ15024 and MJ15025 Outputs are perfect replacements for Your Power Amp...I use them as well. Your tech probably just touched the bias pot, and that was all it took to make it fail (Open up)..If he was savvy, he would have replaced that POT before Touching it.

Hope this info helps....

Eric

Posted on Jan 16, 2009

  • 7 Answers

SOURCE: Studiomaster 900E power transitors

read through this thread and you should be able to get a schematic

http://www.diyaudio.com/forums/showthread.php?threadid=140776

Posted on Jun 17, 2009

  • 733 Answers

SOURCE: I need to find output transistors for a Rockford amp

Call rockfor fosgate and ask if they sell component parts to public, if not, ask who the their component manufacturer is, maybe you can get it directly from them.

Posted on Sep 03, 2009

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SOURCE: speaker blow out with 34vts

Well, this may take some work, but do you have a schematic for the unnamed mystery amplifier?
If so, trace the voltage back to the op-amp chip that's sitting with V+ on it's output with no input, and you`ve found the problem!
Otherwise, if you have an oscilloscope, with no speakers attached, trace the incoming signal until it turns to a DC voltage or til the signal starts riding on a high or low voltage.

Oh, another thing to check, there's usually a couple high wattage low impedance resistors between the power transistors (unless it's a hybrid chip). If one of those resistors opens up, you can have this issue.

Posted on Apr 27, 2011

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I have a sony STR-de135 receiver whlie looking for one problem created another.While the receiver was unpluged I touched and output transistor MN2488 and it sparked now the left channel sounds distorted so...


The capicitors in the unit are charged. Replacing the output transistor(s) is not a task for a novist. Capicitors, resistors, driver transistors and sometime preamp chips can also be bad as well. If all the bad components are not replaced the parts you replace could blow out again.

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I have blown the protection circuit on my yamaha rx 600d amp anyone with a clue whats needed to fix?


Hi friend,when something goes wrong in the output of the amplifier the protection circuit take place to prevent further damage could cause by DC power such as speakers or other related circuits...I think in your situation either one or both output amp stage have blown,then the protection cct turned on (not blown protection circuit!?). If so you have to check all the output transistors for short cct, if shorted you must also check all the DC bias cct nearby such as small transistors,resistors...If you are not familar with amplifier it better to find a tech as all amplifiers need a very precide repair technic , If the DC BIAS were wrong , when you turn on the power it will blow straight away! All times and cost will be waisted!
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1 Answer

No sound out of left speaker


did the left channel work when u switched speakers, if so then the left speaker or wiring is a fault.if not then the output circuits on the amp are blown or the fuse is blown some amps have internal fuses in the output to protect the output transistors. unplug the power cord and take the cover off, look to see if u can find any fuses and check these for continuity u can hold these up to the light and u should see a fine filiment in one piece and not broken. these fuses sometimes blow just from age and use at high volume like a regular light bulb.If the fuse is blown replace with the same value else the output transistors will need to be replaced most likley along with the drivers.

May 19, 2009 | Sony STR-DE135 Receiver

1 Answer

Noisy left hand power output stage. Noisy transistor? No circuit diagram.


If the speaker is not blown, there must be an output capacitor. If no output capacitor, and you have a blown transistor the speaker will blow from DC current. You can further check the transistors with a multimeter. A transistor looks like 2 diodes and you should be abobe to test with a mulimenter like a diode test.

May 12, 2009 | Audio Players & Recorders

1 Answer

Lab l4 bass amp smoked my speakers


Hi,
If your description is to be taken literally, and smoke did indeed come out of the speakers, your output transistors have shorted out, and put the full power supply voltage and current through your speakers.
The amp and the speakers will need to be serviced. The speakers will need new voice coils at the least.

Sep 30, 2008 | Audio Players & Recorders

1 Answer

Mains fuse blows immediatly on power up on trace elliot commando 100W bass amplifier


Hi, The most common cause of this is blown output transistors, assuming this is not a valve amp. 
At any rate, this is something you will want to have looked at by a tech.

Sep 17, 2008 | Audio Players & Recorders

2 Answers

Sansui amp au11000


Without seeing the amp nor having the service manual in front of me, it sounds like you have a severe offset problem. There is either an open resistor or transistor in the early stages. With the output transistors removed from the unit, look around at voltage levels to determine where the fault is. I will try to locate the service manual. Can you post the parts that you have replaced?

Thanks,
Dan

Sep 04, 2008 | Audio Players & Recorders

1 Answer

Blown output on Denon AVR3805


This unit does not use "output transistors". The driver section uses hybrid packs that are usually two to a set. Knowing which set to replace is only part of the problem when replaced as bias voltage Must be correct...accordianman

Mar 03, 2008 | Denon AVR-3805 Receiver

2 Answers

Kenwood basic M2 Amp Lightning strike


you can check the output transistors for short circuits with the low ohms range or diode checker . If they have failed, then it is often a good idea to replace all as much stress can be placed on an output array in this type of failure. to repair reliable, all outputs on an offending channel should be replaced.

Make sure the fuse you replaced was the same type of fuse. check markings.... T stands for sloblo... a fast blo duse may let go at turn on. The power supply may have a shorted rectifier diode in it also.

be aware however, every time a fuse of that rating blows... more damage may be occurring to the amp.

Dec 11, 2007 | Kenwood VR-407 Receiver

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