Hello all; my understanding is that best practice is to replace capacitor’s that are over 30 years old. I recently purchased a Hickok 501a hv adjustable power supply. When I opened it up it looks brand new inside. I don’t see any deterioration of any kind. It powers on and operates fine. The only thing I question is it doesn’t reach the 400 voltage max. It stops around 375 volts. Should I go ahead and change out all the capacitors anyway?
@jodonne22 I would start with testing all caps but expecially the electrolithics because most of tjhe time even though they look nice and shiny like new they can go short in no time at all destroying everything in their path tubes, H. power resistors and transformers as well. A good practice is to actually change them expecially when the subject in question is a power supply that has to be trusted and dependable. Be carefull when testing electrolithics because even though they might test ok with a capacitmeter they are most of the time leaky meaning they become resistive after so many years of service or perhaps just for being stored for years and years. I would go for similar or nerest available values and voltage ratings for all electrolithic caps but making sure I only buy capacitor made by reputable factories such as Nichicon, Rubicon and other well known brands and have them purchased only from trustworthy sellers such as Mouser, Digikey, etc. That way you know you’re getting proper caps. These days there are huge numbers of fake caps for sale on e-Bay and most chinesse sellers looking very legit (at first glantz). So…I would be very careful when purchasing stuff like this. Good luck with your restauration. PS: a good schematic and/or a service manual would save you a lot of head scratching if you can get one in case you dont have one yet.
Thanks so much for your thoughtful response. Great information, I will replace the caps . I do have a schematic and will replace with quality ones.
Best regards
@jodonne22 as Ovi said, test them the best you can first in any case. Depending on what it is and what you plan to do with it, replace them anyway. My heathkit IP32 HV supply got a full rebuild and works great, that’s something you don’t want to fail. Equal or higher voltage ratings, close to capacitance, and always fully disconnect the old capacitors electrically. The max voltage may need to be adjusted as well, mine did.
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@radtekman thanks for the information. I ordered the large caps I have everything else,just waiting for them to come in.
@jodonne22 Wise move and good luck with your restoration, perhaps tell us the outcome and why not showcase your work with some pictures of before and after. Chances are, someone will someday benefit from your successful restoration journey. 😉
No matter how pretty they look, they are still over 30 years old. Change them, you are much better off.
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