Hi there.
I have got a Hhifonics BRX2416.1D with a burned output. I have changed the fet's and got one channel up and running. But the other channel is get a "wrong" dc signal from this little circiut board, and I suspect that the ic U3 migth have something to do with it. This ic has it's marking scraped away, so I can't see what type it is?
I have got a Hhifonics BRX2416.1D with a burned output. I have changed the fet's and got one channel up and running. But the other channel is get a "wrong" dc signal from this little circiut board, and I suspect that the ic U3 migth have something to do with it. This ic has it's marking scraped away, so I can't see what type it is?
That IC gets replaced a lot but rarely fails. It's an LM211/311.
I'd be far more suspicious of the IRS21844 under the copper colored heatsink. They fail virtually every time that the outputs fail.
In the overall photo, the output inductor appears to have some discolored (overheated?) windings. It could be the photo but if they are actually discolored, that may be another problem that you'll have to address.
I'd be far more suspicious of the IRS21844 under the copper colored heatsink. They fail virtually every time that the outputs fail.
In the overall photo, the output inductor appears to have some discolored (overheated?) windings. It could be the photo but if they are actually discolored, that may be another problem that you'll have to address.
I wouldn't recommend that supplier for electronic components.
https://no.farnell.com/en-NO/c/semi...management-ics-pmic/gate-drivers?st=irs21844s
https://no.farnell.com/en-NO/c/semi...management-ics-pmic/gate-drivers?st=irs21844s
Excellent, we do shop from Farnell from time to time, so this is a good find.
Which one of the three shall I chose?
Which one of the three shall I chose?
They only differ in packaging. The top is cut tape (probably the best option). The second appears to be loose. The third is for 100pc+ quantities on reels.
Me back again. Ordered the IC IRS21844S from Aliexpress 🙄 The original ic says IR21844S, not irS
Change the ic and the amp fired up. Sorry for the hair between some of the pins, its from the cleaning cloth.
And, yes the heatsink is solider back in place, just if you was wondering why it's missing in the picture.
The amp is pulling close to 5A and it's rising the longer it is on.
One of the FET's get hotter then the rest. See the blue ring.
If I put my Fluke pin on the bottom leg on the FET, (to measure the voltage) the amps rises straight away. This happening more or less on all four FET's on the left side, but nothing happens if I measure the voltage on FET's on the right side?
Change the ic and the amp fired up. Sorry for the hair between some of the pins, its from the cleaning cloth.
And, yes the heatsink is solider back in place, just if you was wondering why it's missing in the picture.
The amp is pulling close to 5A and it's rising the longer it is on.
One of the FET's get hotter then the rest. See the blue ring.
If I put my Fluke pin on the bottom leg on the FET, (to measure the voltage) the amps rises straight away. This happening more or less on all four FET's on the left side, but nothing happens if I measure the voltage on FET's on the right side?
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Why ali express? You can use DigiKey, Mouser and Farnell are all reputable.
Are all of the outputs from the same batch?
If you swap the hot FET with one of the others, does the heating follow the transistor?
I don't know how much experience you have with these ICs but they're notorious for being damaged during installation, due to too much heat being used. The symptoms you described could well be a damaged IC.
Are all of the outputs from the same batch?
If you swap the hot FET with one of the others, does the heating follow the transistor?
I don't know how much experience you have with these ICs but they're notorious for being damaged during installation, due to too much heat being used. The symptoms you described could well be a damaged IC.
Thanks for the quick reply, Perry.
It's been 20 years since I worked as an audio repair guy, so I have no experince with this ic.
Shall I order the IR21844S or the one with the extra S in it? (IRS21844S)
Will swap the FET and see what happens. If I have got this right, the FET's are wired in parallel, right?
https://no.farnell.com/en-NO/infineon/ir21844spbf/driver-mosfet-high-low-smd-21844/dp/8639043
It's been 20 years since I worked as an audio repair guy, so I have no experince with this ic.
Shall I order the IR21844S or the one with the extra S in it? (IRS21844S)
Will swap the FET and see what happens. If I have got this right, the FET's are wired in parallel, right?
https://no.farnell.com/en-NO/infineon/ir21844spbf/driver-mosfet-high-low-smd-21844/dp/8639043
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The one with the S is fine. It's an 'improved' version. I've never known the improved version to be a problem. I generally recommend ordering the exact replacement but here, I don't know if the S is better since the non-S has been working perfectly fine.
If you didn't apply heatsink compound between the sink and IC, apply a small amount.
When you solder it in, do so quickly. Get it right the first time. Don't apply heat for a long period of time.
If you didn't apply heatsink compound between the sink and IC, apply a small amount.
When you solder it in, do so quickly. Get it right the first time. Don't apply heat for a long period of time.
I would advise NOT to use almost any component from Aliexpress....When i've used it was for parts that i was unable to source from anywhere. 9 of 10 times this would lead to lose the money on the purchase and more in damaged additional components. Not to mention extending the repair time and effort...so please avoid at ANY cost.
I do shop mainly from farnel. it's the only one available here. No issues so for.
Check the gate resistor if it is in tolerance. I would also measure the RDS for this mosfet.
I do shop mainly from farnel. it's the only one available here. No issues so for.
Check the gate resistor if it is in tolerance. I would also measure the RDS for this mosfet.
Thanks for the tip, Lenin.
I have learned from my mistake, so only Farnell from now on.
I have no idea what RDS means?
I have learned from my mistake, so only Farnell from now on.
I have no idea what RDS means?
No FET can pass current with zero loss across the drain and source. The RDS(on) is the effective series resistance intrinsic to the FET across the drain and source (resistance drain to source when the FET is fully 'on'*). Typically, the lower voltage FETs like the ones used in the power supply have a lower RDS(on). Higher voltage FETs like the ones used for output FETs have higher RDS(on). Higher RDS(on) means higher power dissipation for a given current flow. This means that, since power dissipation for any transistor package is limited, FETs with higher RDS(on) will have lower current ratings.
*Fully 'on' typically means that the VGS (voltage gate to source) is approximately 10v. More voltage does little and significantly lower voltage means that the FET will have even more RDS(on).
I don't know what FET your amp uses but the attached is one that's used in larger 21844 amps. You can see that the RDS(on) is 0.19 ohms. For power supply FETs the RDS(on) is often near 0.005 ohms.
*Fully 'on' typically means that the VGS (voltage gate to source) is approximately 10v. More voltage does little and significantly lower voltage means that the FET will have even more RDS(on).
I don't know what FET your amp uses but the attached is one that's used in larger 21844 amps. You can see that the RDS(on) is 0.19 ohms. For power supply FETs the RDS(on) is often near 0.005 ohms.
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