i measure the output of the KIA494 and at pin 9 i found 3.3V and at pin 10 i found 3.7V. i look in a schematic and i found that pin 9 and 10 command the driver transistors in my case A1266. I think that trow the 68 resistors the voltage goes to 3.0V and 3.5V in the "bag area". Also i measure and both driver transistors that comands the transistors with problems are connected toghether to the same pin 10. It is posible by changing this circuit to resolve the problem? The 494 can be influenced by other factors? i look in the schematic and i can't see any pin comming from other circuit.
I will measure what you said. In this moment i don't have acces to the room where is placed the amp.
I will measure what you said. In this moment i don't have acces to the room where is placed the amp.
I discovered another problem... my power supply isn't able to give 7A at 14V, all the measures i done at about 11V. 
and another question: the voltage on the first pin of the mosfet will be much higher at 14V and at 3.7V(measured on the gate) my transistors are getting hot with the power suplly at 11V. It's ok with 68Ohm or i need to replace with 100ohm to be safe??
1970/470/120 IRFZ48 imput/output/reverse transfer capacitance
1800/700/100 original transistor
1900/920/170 IRFZ44
and another question: the voltage on the first pin of the mosfet will be much higher at 14V and at 3.7V(measured on the gate) my transistors are getting hot with the power suplly at 11V. It's ok with 68Ohm or i need to replace with 100ohm to be safe??
1970/470/120 IRFZ48 imput/output/reverse transfer capacitance
1800/700/100 original transistor
1900/920/170 IRFZ44
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i try to repair an amp like that and at 12V it draws 15Amps!!!!
the audio part is working ok, all the transistors were changed with IRF3710, on the supply area i need to change probably the driver circuit KIA494(TL494). Also i changed the transistors with irfz48 and the gate resistors. What can cause suck a big consume? What i need to check/recheck???
the audio part is working ok, all the transistors were changed with IRF3710, on the supply area i need to change probably the driver circuit KIA494(TL494). Also i changed the transistors with irfz48 and the gate resistors. What can cause suck a big consume? What i need to check/recheck???
2 transistors can be damaged? because each line(3 transistors) is drive by a A1266 and in total are 4(A1266) areas in the power supply. I will change those transistors, but i need to say that the KIA494 at pin 9 and 10 gives a difference voltage.
and the consume(15A) comes fron the damaged driver transistors?
and the consume(15A) comes fron the damaged driver transistors?
could you give me the type of other transistors that are compatible with A1266? the part of the amp that has 2 rails of transistors that are getting hot are driven by the same pin of 494 i think 9, and the rest of the amp that is ok is driven by the pin 10. i will change to be sure the driver circuit and the transistors.
Hate to resurrect an old thread but Im having a similar problem with my brutus 1500d. The amplifier keeps cycling between functioning and protect mode, red to green to red ..etc. Once it gets to the green the coil closest to the fuse "squeals" a little then shuts off then cycles again. I have replaced all the amplifier sides mosfets (IRF3710) and ive heard audio come out of it before it goes into protect. Ive also replaced the tip41c (q100)and the FMG22S (D19,D20) The only mosfets I havent replaced are the 65n06's on the psu. All the 100ohm resistors read good. Any guidance would be of help.
I didnt replace the HIP4080. The IRF3710's were not Z's.. Got them on ebay and asked the seller to make sure all were the same batch and were matched, in which they were. The FMG22s's are no longer in stock and I was told to use NTE6240's instead and thats whats in place at the moment. The outputs read in the meg ohms and werent shorted, the only reason I replaced the 3710's is that all the legs cracked off when I took the pcb out to replace the FMG's.
Ebay is notorious for selling parts that are counterfeit or defective. There may be good sellers but I helped a fair number of people who have purchased parts from ebay. Most had problems that pointed to those components. Buying the same parts from a reputable distributor solved the problem. The ones from Hong Kong seem to be the worst.
From my experience, the new non-Z parts will not work, no matter the source.
The 4080 fails virtually every time the outputs fail. If the outputs failed, you need to replace the 4080.
In this instance, the NTE parts will probably be OK but unless you're repairing a television, do not use them. NTE selects a component that meets or exceeds the specs for multiple similar components and uses that part as a sub. That may have been OK in the past but it's not OK when working on newer equipment. Sometimes, VERY minor changes in components (changes that are so minor that it doesn't warrant a change in the part number) can make the components completely unsuitable as replacement parts.
From my experience, the new non-Z parts will not work, no matter the source.
The 4080 fails virtually every time the outputs fail. If the outputs failed, you need to replace the 4080.
In this instance, the NTE parts will probably be OK but unless you're repairing a television, do not use them. NTE selects a component that meets or exceeds the specs for multiple similar components and uses that part as a sub. That may have been OK in the past but it's not OK when working on newer equipment. Sometimes, VERY minor changes in components (changes that are so minor that it doesn't warrant a change in the part number) can make the components completely unsuitable as replacement parts.
I chose a reputable seller that was in the US for the 3710s albeit thats now a hindsight, what should I attempt to try? The 3710Z? I believe I can get the lead frees directly from international rectifier (IR3710ZPBF). I was getting output out of the amp once they were replaced. Before attempting to replace any of the parts the T1P1 coil was squealing like a banshee and it does now like it did before except it appears to get out of protect, go to a green light and then it squeals and goes into protect for a second then the cycle continues. I already have some 4080's on order from intersil, I will replace that once they get in.. but since thats on the amp side does that have much affect on my problem?
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