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Q&A What are these mystery components (one of wire coil, another labeled "100-10L A9")?

The black one is a tantalum capacitor. There are various weird ways to mark these (because typing out 100u instead of 100- would be too easy...). If I'm correct in this case, I believe: 100 stan...

posted 1mo ago by Lundin‭  ·  edited 1mo ago by Lundin‭

Answer
#2: Post edited by user avatar Lundin‭ · 2024-04-03T15:36:47Z (about 1 month ago)
  • The black one is a tantalum capacitor. There are various weird ways to mark these (because typing out 100u would be too easy...). If I'm correct in this case, I believe:
  • - `100` stands for 100uF
  • - `10` for 10V.
  • - `L` is tolerance +/-10%.
  • - From the size of it it looks like a "D package" aka EIA 2917. In plain SI units meaning 7.3mm x 4.3mm.
  • This would then be an equivalent part: https://export.rsdelivers.com/product/vishay/593d107x9010d2te3/vishay-100%CE%BCf-mno2-tantalum-capacitor-10v-dc-593d/6844474?query=6844474
  • These are bulk caps for the supply and the exact value or tolerance won't be important.
  • ---
  • As for the second part, it is some manner of inductor and that's all I can tell. It seems likely that the little black SOT (SOT-89?) IC marked 331 is a switch regulator. You won't be able to figure out the value of the inductor by looking at it, you have to look at the regulator requirements, then find an equivalent part.
  • You may have to reverse-engineer the board and produce a schematic to tell for sure what the 331 IC does.
  • I'm guessing since it runs on AA batteries that it's a boost regulator to 3.3V. There's several parts that might fit the bill, I can't be bothered to track it down.
  • (You could try to just smack on some inductor between 10uH to 100uH and hope for the best... not professional but I've been there, done that. Fully enclosed ones are preferred.)
  • ---
  • Tantalum caps tend to explode with a spectacular pyrotechnic effect if you for example mount the backwards and provide enough power, or if you simply apply way too high voltage etc. So that could be what has happened here. Then some clumsy person tried to salvage the board but failed, removing the solder pads in the process.
  • You may be able to salvage the board if you are less clumsy, by carefully carving off the solder mask from the traces going to the pads with a scalpel or similar precision knife. Then attempt to solder a new cap there. If it is easier mechanical-wise, you could maybe pick a through-hole one of 100uF instead.
  • It might be easier to just desolder anything related to the regulator and patch in a brand new one there instead.
  • The black one is a tantalum capacitor. There are various weird ways to mark these (because typing out `100u` instead of `100-` would be too easy...). If I'm correct in this case, I believe:
  • - `100` stands for 100uF
  • - `10` for 10V.
  • - `L` is tolerance +/-10%.
  • - From the size of it it looks like a "D package" aka EIA 2917. In plain SI units meaning 7.3mm x 4.3mm.
  • This would then be an equivalent part: https://export.rsdelivers.com/product/vishay/593d107x9010d2te3/vishay-100%CE%BCf-mno2-tantalum-capacitor-10v-dc-593d/6844474?query=6844474
  • These are bulk caps for the supply and the exact value or tolerance won't be important.
  • ---
  • As for the second part, it is some manner of inductor and that's all I can tell. It seems likely that the little black SOT (SOT-89?) IC marked 331 is a switch regulator. You won't be able to figure out the value of the inductor by looking at it, you have to look at the regulator requirements, then find an equivalent part.
  • You may have to reverse-engineer the board and produce a schematic to tell for sure what the 331 IC does.
  • I'm guessing since it runs on AA batteries that it's a boost regulator to 3.3V. There's several parts that might fit the bill, I can't be bothered to track it down.
  • (You could try to just smack on some inductor between 10uH to 100uH and hope for the best... not professional but I've been there, done that. Fully enclosed ones are preferred.)
  • ---
  • Tantalum caps tend to explode with a spectacular pyrotechnic effect if you for example mount the backwards and provide enough power, or if you simply apply way too high voltage etc. So that could be what has happened here. Then some clumsy person tried to salvage the board but failed, removing the solder pads in the process.
  • You may be able to salvage the board if you are less clumsy, by carefully carving off the solder mask from the traces going to the pads with a scalpel or similar precision knife. Then attempt to solder a new cap there. If it is easier mechanical-wise, you could maybe pick a through-hole one of 100uF instead.
  • It might be easier to just desolder anything related to the regulator and patch in a brand new one there instead.
#1: Initial revision by user avatar Lundin‭ · 2024-04-03T15:34:22Z (about 1 month ago)
The black one is a tantalum capacitor. There are various weird ways to mark these (because typing out 100u would be too easy...). If I'm correct in this case, I believe: 

- `100` stands for 100uF
- `10` for 10V. 
- `L` is tolerance +/-10%.
- From the size of it it looks like a "D package" aka EIA 2917. In plain SI units meaning 7.3mm x 4.3mm.

This would then be an equivalent part: https://export.rsdelivers.com/product/vishay/593d107x9010d2te3/vishay-100%CE%BCf-mno2-tantalum-capacitor-10v-dc-593d/6844474?query=6844474

These are bulk caps for the supply and the exact value or tolerance won't be important.

---

As for the second part, it is some manner of inductor and that's all I can tell. It seems likely that the little black SOT (SOT-89?) IC marked 331 is a switch regulator. You won't be able to figure out the value of the inductor by looking at it, you have to look at the regulator requirements, then find an equivalent part.

You may have to reverse-engineer the board and produce a schematic to tell for sure what the 331 IC does. 

I'm guessing since it runs on AA batteries that it's a boost regulator to 3.3V. There's several parts that might fit the bill, I can't be bothered to track it down.

(You could try to just smack on some inductor between 10uH to 100uH and hope for the best... not professional but I've been there, done that. Fully enclosed ones are preferred.)

---

Tantalum caps tend to explode with a spectacular pyrotechnic effect if you for example mount the backwards and provide enough power, or if you simply apply way too high voltage etc. So that could be what has happened here. Then some clumsy person tried to salvage the board but failed, removing the solder pads in the process.

You may be able to salvage the board if you are less clumsy, by carefully carving off the solder mask from the traces going to the pads with a scalpel or similar precision knife. Then attempt to solder a new cap there. If it is easier mechanical-wise, you could maybe pick a through-hole one of 100uF instead. 

It might be easier to just desolder anything related to the regulator and patch in a brand new one there instead.