Hi there does anyone know if FB42n20d fets were originally used in these amps im having issues I was trying to repair the potentiometer because it was fluctuating current when turned the speakers were moving in and out and was working fine before that for 15 minutes but when adjusting the potentiometer the current seemed to be fluctuating then all the sudden the second light inside the amp at led 238 went out followed by the power light is this something simple that could be wrong it the amp I hope
Seems to have been overheated because I let the amp cool off then repowered the amp and it seems to be working fine again I also noticed the inductors near the transformer were running hot but the amp did not shut off on me until I was messing with the gain potentiometer it seems that its screeching and I even tried to get some litium grease into the shaft but no luck considering I know these are greaseless but it didn't hurt to try does anyone think that could be causing my overheating problem how do I find a new potentiometer? I have mtx thunder 4202 amp sitting around but I don't know if the ohms are the same
oh ok I thought I would ask it seems so similar to the mtx 1000d so I thought they might have used the same as the 1000D I think they were snp something it appears they havnt been changed out still looks like the factory solder just wasn't sure tho about the IRFB42N20D you wouldnt happen to know the potentiometer size for the gain by anychance would you?
yes i still have the original one installed its grn same size as my 1000d gain potentiometer but that one is blue and has a 500 number on the side if you would like a picture i could snap one for you later i know the one next to the problem potentiometer has 50k stamped on the backside of the potentiometer which is the same size but for all i know the gain is different also with a defective gain could that cause the amp to heat up? like by the power inductors and the metal bars i call them buss bars theres 2 of them near the fets about a inch long soldered to the board ? the potentiometer when powered tends to make my subs bounce up and down the grease seemed to help alittle also tested the potentiometer while powered to the subs and the rcas disconnected it does the same thing but itll only cause the subs to bounce when moving the gain knob
In the future, please leave a blank line between each individual thought, question, statement. It makes it MUCH easier to read quickly.
The subs moving when the gain knob is turned is due to a bad VCA (voltage controlled amplifier). That's the 8 pin IC behind the telco jack (U141). Mouser has them. The pot is likely OK.
If you're referring to the shunt resistors (attached)? Those are used to monitor current flow. They should only get hot when the amp is driven hard.
What is heating up on the amp (specifically)?
The subs moving when the gain knob is turned is due to a bad VCA (voltage controlled amplifier). That's the 8 pin IC behind the telco jack (U141). Mouser has them. The pot is likely OK.
If you're referring to the shunt resistors (attached)? Those are used to monitor current flow. They should only get hot when the amp is driven hard.
What is heating up on the amp (specifically)?
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I have a extra THAT 2180B I purchased from mouser for my 1000d laying around will that work?
Also on your picture of the Shunt theres 2 regulator coiled behind the shunts those get hot and the shunt however if the voltage is fluctuating from the VCA couldn't that cause those items to heat up?
I mean cause it got so hot I didn't know it and the amp shut off I thought something blew up that's when I discovered the shunts hot and the regulators but I let it cool off then reconnected the amp to my car battery and it worked again the led238 light went out first when it was acting up followed by the power led
I was trying to run 2 Fosgate HX2's Dual coils 500 RMS im assuming 250 RMS per coil
Also on your picture of the Shunt theres 2 regulator coiled behind the shunts those get hot and the shunt however if the voltage is fluctuating from the VCA couldn't that cause those items to heat up?
I mean cause it got so hot I didn't know it and the amp shut off I thought something blew up that's when I discovered the shunts hot and the regulators but I let it cool off then reconnected the amp to my car battery and it worked again the led238 light went out first when it was acting up followed by the power led
I was trying to run 2 Fosgate HX2's Dual coils 500 RMS im assuming 250 RMS per coil
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If the pin configuration is the same (look up both datasheets), it should work.
Do you have the thermal gap pad on top of the inductors that pass heat to the cover of the amp? The image below shows a similar amp. Yours may need 2 of those pads per inductor to make good contact.
Do you have the thermal gap pad on top of the inductors that pass heat to the cover of the amp? The image below shows a similar amp. Yours may need 2 of those pads per inductor to make good contact.
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The NM taper is a balance pot configuration. The attached photos shows the internals and the taper. Look closely at the individual N and M tapers. Both go to a direct short at the center position. The following datasheet is for a balance pot of a different style.
http://www.mouser.com/ds/2/54/PDB182-GTRB-27641.pdf
These plastic pots are very nearly impossible to remove from a double-sided board without damaging them.
http://www.mouser.com/ds/2/54/PDB182-GTRB-27641.pdf
These plastic pots are very nearly impossible to remove from a double-sided board without damaging them.
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