So, there I am… sat at the workbench, head buried in my latest creation when I start to get a feint smell of something. I know that smell. It’s the smell of burning components. My immediate though was the project I was working on was about to go up in smoke, but it wasn’t powered on at the time. A quick glance around shows the room definitely has a smoke haze forming and I quickly trace it to my spectrum analyser. I switched it off, cleared a space on my bench and whipped off the lid to see what was going on. As it happens, it’s been playing up for a while now and I’ve been meaning to get around to having a look under the hood as it were. I was really worried as this piece of kit has three 6v SLA batteries inside and I thought if there was a short circuit, it’s not a quick job to remove them.
A close-up inspection revealed the culprit – a tantalum capacitor on a small voltage regulator board (front left and black).
For me, tantalum capacitors are a complete pain in the ass. They always seem to fail by going short circuit and produce the most horrible smell. They can also cause a LOT of damage to the surrounding PCB if you don’t catch them in time.
Anyway, PCB removed, both capacitors exchanged for standard electrolytics and everything now works a treat.
If you have ever wondered what happens if you don't cut the power in time, the pictures below are from the battery backup board in my Nixdorf 8870 mini computer. "ONE" tantalum failing caused all this damage.
I never did manage to get rid of the smell completely.
Personally, I don’t know why tantalum capacitors don’t have an in-built piece of fuse wire !!!
A close-up inspection revealed the culprit – a tantalum capacitor on a small voltage regulator board (front left and black).
For me, tantalum capacitors are a complete pain in the ass. They always seem to fail by going short circuit and produce the most horrible smell. They can also cause a LOT of damage to the surrounding PCB if you don’t catch them in time.
Anyway, PCB removed, both capacitors exchanged for standard electrolytics and everything now works a treat.
If you have ever wondered what happens if you don't cut the power in time, the pictures below are from the battery backup board in my Nixdorf 8870 mini computer. "ONE" tantalum failing caused all this damage.
I never did manage to get rid of the smell completely.
Personally, I don’t know why tantalum capacitors don’t have an in-built piece of fuse wire !!!
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