Re: Mosfet Power dissipation question
Also what do you mean the range is fairly large?
They were both operated in the same amplifier and bias set the same etc but I noticed the NF was hotter. I explained it again just so it was clear.
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Re: Mosfet Power dissipation question
Wowzer information overload!
I would love to fully understand it but as mentioned before the service manual states the idle at 160-180 and both times was set to 160 but was noticeably hotter with the NF.
I have attached link to service manual. If NF is an upgrade 95w is better? Lower numbers are better? Thanks
https://www.hifiengine.com/manual_li...nad/c300.shtmlLeave a comment:
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Re: Mosfet Power dissipation question
It appears the NF was supposed to be an "upgrade" to the NE, but these were meant to be run in switch mode. Running them in forward-active analog mode the improved parameters don't matter as much.
The 130W for the NE and the 95W for the NF are package limits and don't have anything to do with how much an application will dump heat. In all honesty dumping 130W from a TO-220 is tough to unlikely anyway.
I don't have the schematic handy but it's possible the bias point for the gate to position the transistor from cutoff into linear vs switching mode is different between the transistors and you may need to tweak the bias. The thresholds of the transistors are specced similarly but the range is fairly large which makes a difference when running in linear mode.Leave a comment:
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Mosfet Power dissipation question
Hi guys,
I have a Nad C300 with the outputs blown. It uses original part STP55NE06L which is not readily available. The suggested replacement STP55NF06L is readily available. But I noticed that the amplifier now runs hotter even with the same bias etc.
The data sheet states the original is 130w power dissipation and the replacement is 95w. I dont understand the other parameters either
Can anyone please help me to understand if this is why it is running hotter than before?
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I tried to use this method:
Testing an N-channel MOSFET:
Step 1: Discharge the Gate (turn off the MOSFET)
Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.
Step 2: Charge the Gate (turn on the MOSFET)
Now, place the red probe on the Gate (G) and the black probe on the...09-27-2024, 03:31 AM -
Hello everyone, I recently found this badcaps site and super Learn Electronics Repair youtube channel. And I wanted to learn how to troubleshoot power supplies and VGA cards and how to practice soldering, since I already have a properly defective piece of them. I am currently trying to solve two problems:
I have a Gigabyte GV-RX460WF2OC-4GD type card. I managed to find the faulty MOSfet (AON6414A) on it, which I replaced. The card starts up, but after about half a minute, the MOSfet in the same position will be shorted again. Is it possible that the PWM controller driving the MOSfet... -
I have a Razer laptop (RZ09 MB# CH570_MB_NT) that has a shorted mosfet marked BND M03 E067 that I'm unable to find anywhere online. Does anyone either know what the part number is for this mosfet or have a schematic I can find it in?
Backstory on the whole thing the laptop was plugged into a lamp at a hotel. The lamp got unplugged while it was charging and now the system won't power on anymore. I found the caps around this mosfet shorted and when I injected voltage into the caps the mosfet got hot and my bench psu was pulling 5A. Pretty sure this is all that's wrong with the laptop... -
Hey guys,
i have a asus motherboard here and as the title says after the first mosfet (in the picture) there is nothing more than 3.15v.
I injected 19v and max. 1 amp at the charging port and there is not voltage drop or smth. It's just taking 19v and 1 milliamp.
Then i tried to inject 19v and max 1amp after the current sensor and there it first takes 19v and 4 milliamps and after 2 seconds it is taking nothing (no current).
I measured on the coils on board everything seems fine. Also the main power rail is not shorted (infinite resistance).
Now i thought something... -
The board number is GU502DU. I repaired this a couple weeks ago and it came back with the same issue, same mosfet failed (PQH9201). I'm hoping that the GPU was spared this time.
I used the same replacement part (purchased from Mouser) and I'm certain the soldering was done properly since it took just as much effort to remove as before. What could cause this same mosfet to fail? I'm thinking if it was unsuitable then the others would fail too. I looked for similar failures on YTube and the mosfet was replaced with AOE6930 in one instance and AOE6932 in the other but it's possible that the...
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