EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: CaptainJinx on September 08, 2018, 01:21:50 pm
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So I'm starting a new project to learn more and gain experience.. I recovered an old TDS544A in desperate need of some capacitors and cleaning because of them. Many folks have done this before with some success. They are 10v 33uf caps. Is it worth going to 15v since they all seem to have failed or is it just more about the fact that they're electrolytics that haven't been touched in years.
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If there is physical space then yes, go ahead and go with higher voltage. IIRC there are a few caps in these scopes that get run beyond the rated voltage of the original parts. I used tantalums on the video trigger board I put in my TDS784 but you do need to be careful, apparently some of the regulators used in some areas of these scopes rely on the ESR of electrolytics to be stable.
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I replaced all electrolytics in my 540A with tantalums with no issues whatsoever. The unit is going strong for many years since.
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It usually works, but you can have issues with the ones used as decouling for linear regulators on the board. If in doubt, read the datasheet for the regulator used. The caps in question will be easy to identify as they are in close proximity to regulators.
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I strongly recommend to use electrolytics because some parts of the TDS500/600/700 series have been designed to use electrolytics. Tantalums also require the power supply not to ramp up too quick or they blow/short.
There are also a few capacitors which have more than 10V across them so using higher voltage electrolytics is a good idea.