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 Post subject: Zenith Royal 7000-1 recap question
PostPosted: Feb Fri 07, 2020 4:56 am 
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Joined: Nov Tue 15, 2011 11:19 pm
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Location: Woolwich Twp (Swedesboro), NJ
I have the parts list and there is a nice PDF on how to recap. There are 11 electrolytic caps. Many are odd values like 500, 300, 20, 5uf. How critical is it to get close to these values? Can I use standard 470, 330, 22, 4.7uf, etc?

Typically in transistor radio, I would just replace non-standard with a standard value. But this is a later model from the early 1970s, and was a little surprised they had all these non-standard values.


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Feb Fri 07, 2020 5:48 am 
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Location: Mountains of Mourne. Ireland.
Yes, those are the correct modern-day common values to use.
viewtopic.php?p=2864980#p2864980
All within respectable margins... :)

fyi... many electrolytic capacitors produced in the late-1960s / early-1970s had a standard tolerance of ±10% or ±20%
with some, depending on voltage rating, specifying a range of -10% to +250%


What is the percentage increase/decrease - from ? to ?
https://percentagecalculator.net/

Greg.


Edit: Padgett Peterson's archived web-pages.
viewtopic.php?p=3111337#p3111337


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Sep Mon 21, 2020 1:44 pm 
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I know that one can use capacitors with a higher voltage rating to re-cap a radio but is there a limit to how high you can go? Specifically I wish to replace the 1mfd @ 25v caps in the Royal 7000-1 with 1mfd @ 160v. I remember reading "somewhere" that going way higher with the voltage rating was detrimental in some cases. Regards, Ed


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Sep Mon 21, 2020 9:28 pm 
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I've seen people say in forums that the modern 25 or 35v caps are similar in characteristics to the originals. Often a modern electrolytic will test much higher than it's rated at,and still be within tolerance. So a 470 may very well test closer to 500uf anyway. They do make 500uf caps,but they're very expensive. I would go with the 470.


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Sep Mon 21, 2020 11:49 pm 
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Location: Mountains of Mourne. Ireland.
Not sure if I would employ a 160V electrolytic for a 25V one.

Using a high Voltage capacitor in a low Voltage circuit may cause your capacitor not to behave correctly.

If you want a good rule of thumb - - stick to sensible increase of ~2X WVDC (working voltage).
I.e. replace a 1960s/70s 1μF 25V with 1μF 50V


Greg.


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Sep Tue 22, 2020 2:56 am 
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Joined: Apr Tue 12, 2016 3:51 am
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Thank you Greg. Unfortunately I have already installed the 160v 1mfd caps in the 7000-1 and it seems to work OK, but since they are in the audio section of this receiver I will probably order the right caps and replace them. Regards, Ed


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 Post subject: Re: Zenith Royal 7000-1 recap question
PostPosted: Sep Fri 25, 2020 2:36 am 
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Posts: 541
Location: Woolwich Twp (Swedesboro), NJ
Ed in W. PA wrote:
Thank you Greg. Unfortunately I have already installed the 160v 1mfd caps in the 7000-1 and it seems to work OK, but since they are in the audio section of this receiver I will probably order the right caps and replace them. Regards, Ed



I go slightly up in voltage. Like a 35V for a 25V. Anything below 25V I replace with a 25V because the size if much smaller these days. If I have a 150V, I go with 200V.

However, if you have a 25V and replace it with 200V, it will work fine. But the size difference is big. Also, as you go up in voltage, you go up in price. So don't do the overkill by replacing a 25V with a 200V.


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