Quick capacitor question

[Stlouisian]

I just recently got a Zenith 24NC31 and I would like to temporarily replace one of the electrolytics that is rated 80 Mfd and 475 Volts with two 40 Mfd 450 Volt electrolytics in parallel. If this would not work do I need to get two 40 Mfd capacitors rated at least 475 Volts and put them in parallel. Thanks,

Ross

[Lefty]

Well with no additonal information then the safest advice is to use two new 40MFD @ 475 WVDC. However the actual voltage that the caps see in the circuit would determine if you could use the only slightly lower voltage caps you have. If possible you could try and measure the circuit voltage at the existing caps and see if is 450 vds or lower. There is usually a safety margin in component specifications and you likely might to able to utilze the lower voltage caps.

Just work safely...

Lefty

[Eric H]

It's never a good idea to use a lower voltage cap, 25 volts difference might be OK for a temporary test but I would hook a meter to it and see how much voltage is actually there before I ran it long. Sometimes the turn on surge can be higher even than the rating of the original caps!

Yes, you can hook two 40mf@475v caps together in parallel to make an 80mf@475 cap

[Charlie]

I was wondering how well the oil filled caps hold up over the years? My CM 23" from '63 is loaded with oil filled .047mfd 600 volt caps. Back when I recapped that set, I only changed Black Beauties and lytics... leaving the .047 oil caps in there. Has anyone had these in a set, and noticed a difference after replacing them?

I'm putting some fresh lytics in it because the overall performance has been a little weak... come to find out the B+ was running low. The lytics I installed 10 years ago were NOS... the style in the cardboard sleeve... and probably at least 15 years old when I bought them. Now, I'm going to install fresh stock lytics. I'm also considering changing the oil caps, but was curious to hear what others had to say about them? Are they as unreliable as any of the other BB's or paper wax caps? Or do they hold up well?

[drh4683]

there is no problem using 450 volt caps in place of 475 volt caps. The 24NC31 has B+ voltage NO HIGHER than 350, so you are perfectly safe in doing this. Since this is a filter cap, you can run the two 40's in parallel.

[AudioMixer]

Hey Ross, I think I may have found it. Click here http://digikey.com/

and in the parts search box type in this part number P7447-ND

82uF/500v cap

Hope this helps.

Originally Posted by Stlouisian

I just recently got a Zenith 24NC31 and I would like to temporarily replace one of the electrolytics that is rated 80 Mfd and 475 Volts with two 40 Mfd 450 Volt electrolytics in parallel. If this would not work do I need to get two 40 Mfd capacitors rated at least 475 Volts and put them in parallel. Thanks,

Ross

[Chad Hauris]

You can get new Sprague Atom 500 volt rated electrolytic caps, we use them a lot of the time in jukeboxes.

[Charlie]

Apparently, I used poor judgement in placing my oil-filled capacitor question in this capacitor thread. It seems everyone is answering Stlouisian's original question... one that he asked back in May 2004.

[blue_lateral]

Charlie- What do they look like? The original black beauties were oil filled, and I was under the impression that all similar things were basically a disaster. Going by those screenshots you posted in another thread, how bad could they be?

John

[Charlie]

Blue Lat,

The caps are not in my CM roundie... they're in my 63 CM B&W set. Unfortunately, this set is at my cabin and I'm at home right now... so I can't post a pic. I don't have any other sets containing these caps.

These caps are Japanese made, a little shorter than a BB cap, grey color, axial lead, with "Matsushita Oil Filled" printed on them. ALL of the .047's in this set are this style.

I thought black beauties were the same as the paper/wax caps... except for the shell. Didn't realize they started out as oil filled.

[blue_lateral]

I've been told there are three kinds of black beauties. The first kind are the ones with the big solder blob at the end. The blob is the little funnel they used to put the oil in, soldered shut. The just might be the worst capacitors ever made. The second kind is just paper, but probably less reliable than the wax/paper kind. The third kind is actually a mylar cap. Those are fine, and you can tell them by the color of the lettering if you know what the "right" color is, but I don't.

I wouldnt trust any oil caps very far... but I have no experience with the ones you describe. It might make an interesting little experement to test a few of them with a vtvm.



John

[Adam]

These caps are Japanese made, a little shorter than a BB cap, grey color, axial lead, with "Matsushita Oil Filled" printed on them. ----------

I have a Magnavox b/w portable that had some of those in it. If I remember correctly, none of them were actually bad, but I changed them all anyway soon after I got it, so they never saw a lot of use.

[Charlie]

This set has seen lots of use over the years. It was bought second hand by an uncle that used it for years, then passed it around to his younger siblings as they moved out and got their own places. By the time I got it, it had some miles on it!

When I changed the caps years ago, I mainly installed electrolytics. It was loaded with Blk Beauies and these oil caps. I only changed half of the BB's as most of them checked good. ALL of the oil-filled caps were left in there since they checked good as well.

Through the years, experience and other AK-ers have taught me BB's will cause little issues even though they might check right on the money... so now days, they ALL get replaced.

For now, I think my plan will be to change out the 2 lytics in the B+ that were kinda old (these were the old style I installed 10 years ago- they performed fine then, but are leaky now) and then change the remaining BB's that are in there. I think I'll leave those oil-filled .047's in there and see how it performs.... then go from there.

I noticed the picture getting weak this past year. Considering the high milage this set has seen in 43 years, it kinda surprises me that it plays at all!

On a side note, the stereo in it still has ALL of the original caps in it... Blk Beauties, lytics, and oil-filled! It still plays great. No hum, static, or any other issues!