This is from a Synology 1815+ motherboard. I believe one is a transistor, and the other is a resistor. I’m wondering if you could help me identify an SMD chip that I could purchase from DigiKey that is located in the picture in Q4 and also at, I believe it’s R32. Both are highlighted in red.
Hello,
Welcome to the technical forum.
You can look at part number MMBT3904LT1G on this link : MMBT3904LT1G onsemi | Discrete Semiconductor Products | DigiKey. This shows the 1AM for the part mark.
For the resistor can you provide the dimensions? Als it the full part mark 010 or C10?
It definitely says 01C, but the 01C is bigger than the one I need which is the one located in I think R32?
I’m not sure if I’m measuring it correctly with my caliper, but it looks to be around 1mm x .5mm.
I am confused on the part mark and also the size. This would make it a 0402 . The reason for the confusion is this is usueally so small they are unable to mark the part. I am not sure on what the C is . I am guessing the value is .01 ohm like part number P19181CT-ND on this link:
You can review this to see if you agree. Otherwise you can see if anyone else has something else it might be.
I’m sorry about the confusion. The 01C chip is slightly bigger than the one I need to replace.
You’ll see in this picture the chip is missing. I think I may have mislabeling it. I believe r13 is where it is. But you’ll see two solder points with a missing smd.
This one we would need the value. Becuase it is small and not listed , that might be hard to find out. The resistor is totally gone.
I have a working motherboard where the chip is still there. Do I have to remove it from the board to get a reading or can I read it while it’s soldered to the board?
You do need to break contact with one side to measure it.
I’d assume R32 and R13 would be similar, if you can get R13’s value…
I found on Reddit, a few posters have swapped Q4 for BC846 : Reddit - Dive into anything
1AM = OnSmi NPN: https://www.onsemi.com/pdf/datasheet/mmbt3904lt1-d.pdf
Regards,
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I’m extremely grateful for the info! I will get a reading on the other chip.
I was able to remove it and measure it. It measured at 0.3 ohms. Unfortunately it was so small that it got flown when I pressed the two diodes against each side. Any suggestions on how to avoid that going forward?
Nerd
Take a look at the link these are the .3 ohm resistors we have to offer in 0402 size , I am not sure what the tolerance s though ,
I thought I’d update this post in case anyone else encounters this problem. I bought ERJ-2LWFR010X Panasonic Electronic Components | Resistors | DigiKey and was able to use them to replace R13 and R32 on the 1815 motherboard. I also replaced the transistor with a Chinese one from Amazon because the ones I bought from Digikey appear to be the wrong ones.
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