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#1
06-15-2020, 06:24 PM
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What's the conventional wisdom on NOS electrolytics?
I need to replace the filter on a 1969 Zenith, and having a tough time finding anything suitable here that's not going to run me nearly 40€ by the time I pay shipping etc., plus mounting on a new terminal strip.
However, an ebay search turned up a NOS version of the exact Zenith part number from the same vendor here in Spain I usually buy my tubes from, for nine bucks. https://www.ebay.es/itm/ELECTROLYTIC...7/132508791869 Common sense tells me it's probably not a good idea, that it will likely be dried out or worse, but given the price and convenience for mounting and installation, not to mention the novelty, I figured I would run it by the smarter folks here. What say you guys? Can I use it? N.b., TV won't be a daily watcher. 
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#2
06-15-2020, 06:41 PM
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I think your common sense is correct. It is mostly age that causes them to go bad. In fact using them tended to keep them in better shape. One use for NOS can electrolytic caps is using them as a starting point for re-stuffing.
Last edited by Notimetolooz; 06-15-2020 at 06:52 PM.
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#3
06-15-2020, 06:45 PM
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It’s your money and your choice, but I wouldn’t advise messing with old electrolytic caps, NOS or otherwise. At best it’s a crapshoot, and you could end up spending more money in the long run by replacing them more than once.
Electrolytics are a wear-item with a finite shelf life, and I’d think you’d be happier with good-quality new parts from a reputable manufacturer & supply chain. However, it’s your decision.
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#4
06-16-2020, 01:45 AM
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Definitely test before using. Hook up to an HV PSU via a resistor and meter. If it reforms quickly it's probably OK. I'd then leave for at least 24 hours on soak to prove the point.
A friend once tested a batch of NOS 450V electrolytics. Fairly small ones. He said that 99% were fine. While old small electrolytics are usually pretty horrible, whether NOS or used, the big cans seem to survive well and will usually reform OK. As Notimetolooz said, if it's one where appearance is critical and it's faulty then re-stuff.
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#5
06-16-2020, 11:59 AM
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I'd get some new production 330uF caps at the cheapest voltage rating 200 or higher from a parts vendor like Digikey. I'm pretty sure it won't cost more than $15 for 2 modern design lytics like that, but then again I don't know how supply chain works in other countries. You can probably zip tie 2 new PCB mount lytics somewhere discreet under chassis, add a terminal strip near the old can and run wires to the new ones....That would be my first choice in that circumstance.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#7
06-16-2020, 04:54 PM
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If original not bad I would keep the old one in.
If there is a big blob of mung under it change all even if still working. If one section bad just clip it out. It was the usual patch in home, would change all if in the shop. Keep in mind the NOS is also probably 40 yrs old. 73 Zeno  LFOD ! .
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#8
06-17-2020, 05:43 AM
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Thanks everyone for the input. Old one is open.
I would love to replace with some new ones from Mouser or Digikey; it's minimum 20€ for shipping from them, and things are simply not arriving anymore from overseas. Here's where my last shipment from the US, which was sent on May 8, is, no further info available except they insist it's not lost: May 24, 2020 at 9:08 am Processed Through Regional Facility CHICAGO IL INTERNATIONAL DISTRIBUTION CENTER So I'm going to try to use parts available here in the EU. Nobody that I can find has electrolytics near the value I need, and those who do claim to have them in stock turn out to be shipping no-name Chinese ones from...China, for delivery in August. I think I'm going to give it a try. Seller says I can return it if it's not good. I have good experience with him.
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#9
06-17-2020, 09:17 AM
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Quote:
https://www.reichelt.com/ca/en/alumi...ct=pos_1&nbc=1 If you do get the NOS capacitor, make sure to re-form it, and check it carefully for leakage and value before putting it into the TV. There's instructions online for reforming capacitors. I do believe though that it is not a good use of your effort to install such an old part as a replacement, because it is unlikely to be as reliable as a new part will be Last edited by maxhifi; 06-17-2020 at 09:23 AM.
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#10
06-17-2020, 10:39 AM
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Wow thank you for that link! Despite a lot of googling that site hadn't come up. I'll pick up a couple of those plus some others that I need for other projects. What a great resource.
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#11
06-17-2020, 10:41 AM
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Another option (if brand new is off the table) is to pull the cap you need out of a newer device. Every modern switch mode power supply from your phone charger up to the 1kW PSU in your desktop directly rectifies the line AC and filteres it with one or two 20-1000uF caps with a DC voltage rating higher than the AC line voltage.
Analog SDTV era TIVO boxes usually have a 330uF 200V cap in them here in the US...not an ideal solution but if you have access to ewaste and or cheap used modern electronics to part out it is an option.... I used to use a good bit of used parts back in college and I'm still not above the practice under certain circumstances.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#12
06-17-2020, 10:50 AM
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Quote:
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#13
06-17-2020, 12:19 PM
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Quote:
 I picked up some Panasonics for two bucks apiece.
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