Alguien puede decirme que es este componente SMD?
Anybody knows what is this.
LDERAS
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It is SY8088AAC
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Sorry, I cannot identify this one for you.
Olá @bostonlito77 ,
The shown component is certainly with certain certainty an LDO. The closest marking match is NCP734, but the pinout won’t match (pin 4 is NC on the NCP device, but is routed on the PCB. Well, sometimes unused pins are attached to copper for better thermal performance, but is unlikely here. Also the NCP device is 3.0V, which would be a bit heretic for an MCU supply. Could the third letter be “F” instead of “E”?). If the chip is some other LDO, then the pin 4 is possibly a “sense” pin, typical for an LDO that can be used as fixed or adjustable.
Is the pin 2 connected to ground?
Cheers, heke
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Yes PIN 2 is connected to ground
Olá @bostonlito77 ,
Please explain what is the problem that you are facing with that device.
Cheers, heke
Thanks for your answers.
The problem is that I can’t find which component it is with the serial number on it LDERAS(enlarged photo attached). Also now I have doubts because the user Adam7 proposed one component to me and yours a different one as you can see in the photos.
I need to know which one it is exactly to buy a replacement since mine is shorted.Given the board connection, your proposal suits me better. Pins 1 and 3 are connected to positive and 5 and 4 are also connected. Could you confirm?
If yours is the correct how can find It with other serial different to NCP561SN30T1G.
Regards.
Hi @bostonlito77 ,
If we assume that it is an LDO, then the only thing unknown is the output voltage. Usually a gadget using a microcontroller runs at 3.3V or 1.8V. That ST’s MCU can take 1.7V to 3.6V.
A bit wider area photo would be nice. There seems to be a display on-board. Also the Atmel’s chip in the upper corner of the photo look interesting.
What is the power source for this gadget? The black plastic thing resembles a battery holder.
Cheers, heke
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Hi again,
The device in question is a Chinese tester. It takes 3 batteries of 1.5v each, making a total of 4.5v. I also add a larger photo without the battery holder.
Regards.
T.jpeg)
Wrong answer this is not right.
I took look at everything here, and I have to say I’m stumped too. Sorry we’re not having much luck so far.
Hi @bostonlito77 ,
The big chip is a multimeter chip from GCE. Could not find a datasheet, but there is an older version of the chip FS9721 by Fortune semiconductors (which unfortunately seems to be retired).
https://www.ic-fortune.com/eng/new_product3_3_1.asp?pno=FS9721_LP3
The datasheet recommends using +3.0V supply thus a fair guess is that the LDO is indeed a 3.0V type. Try to power up the multimeter by connecting two 1.5V batteries in series to the LDO pin 5 (+) and 2 (-).
Cheers, heke
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Hello again, thank you very much for your answers.
Finally I have tried powering the board directly with 3v and I have seen that the same problem continues, so it is not the LDO, which by the way you got right. I attach video. Any ideas? I have tested the fuses, diodes, transistors, measured resistances, the LDO. The problem started after a DC surge.
[image]
Hi @bostonlito77 ,
As the auto-ranging has got mad, probably the GC7721 chip has gone south. Do you get any range OK when doing manual ranging? You can find some GCs on sale in ebay.
Cheers, heke
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Thank you for your help and your prompt response, I’m afraid that if I’m going to have to change the IC, I still don’t understand why the LDO gets so hot but its output reads a constant 2.97V, which I understand is normal.
LDOs tend to get hot. There is a fair amount of wattage wasted as heat.
Thanks for the information
Regards