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Cap Coupled Receivers?

Need some help please. Ran into a small cap on the STK board right against the fuses in the middle that's hard to read. 50v 4.7uF is stamped on it. Does that sound right ?
Thanks !
 
Do you have a service manual to cross check the values on? Although the existing cap is the one to follow the specs on, they usually match the SM, and it's easier to read if the caps aren't in the wide open.
 
Steven Tate said:
Do you have a service manual to cross check the values on? Although the existing cap is the one to follow the specs on, they usually match the SM, and it's easier to read if the caps aren't in the wide open.
Click to expand...

Finding the SM seems impossible. I did find something though & I might as well go ahead & get it. I contacted them & they said it contains Tuner Alignments, component layouts for the boards, wiring diagram for the amp board (schematic ?),
tuner stringing diagram. They also wrote Semiconductors item type NO & part NO (Whatever that means), & a parts list. It may help but I'd rather have the SM.

https://www.samswebsite.com/en/photofact/search/index/model/RA200A
 
Nichicon PW series caps are 105 degree rated and highly regarded by many AKers for use in power supplies and amp boards. Mouser part numbers would start with UPW-
 
p.s be aware some small value might be non polarised . quick way to tell is if they dont have the black - line on one side .
 
SCOTTY#1 said:
Thanks guys ! Can all radial type caps, (including the big can type) be obtained with temp ratings ?
Click to expand...
In general, yes. But in lower power receivers, it's not that important, and even in higher power receivers (talking solid state here), it's usually the PS and amp boards that tend to get hot enough to matter. 85 degree is fine for most components.
 
I think I need a crash course on caps. I went on Mousers site & got confused. I tried to start with the can cap, 75v 2200uF. I couldn't find a Nichicon. I enlarged their pic & the values were way off. :dunno: :confused:
Can anybody that has time PLEASE send me a link for a GOOD replacement for the can cap pictured below ?
@ least 75v long life Thanks !
I'll try to start on Mousers site with the smaller ones for now.
Cheers !!

PB030243_1.JPG
 
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You're probably going to be looking at a cap with snap in terminals. You just have to solder ring terminals onto the snap in terminals. Lug terminal caps are getting harder to find. Nichicon Gold Tune caps are popular as audio grade filter caps. Here are two to look at. The 63v is 30mm in diameter and the 80v is 35mm. Check the existing one and see if one of them matches the diameter so it will fit the clamp.

https://www.mouser.com/ProductDetail/Nichicon/LKG1J222MESBBK/?qs=sGAEpiMZZMtZ1n0r9vR22d%2blFeYd%2bH4EbGD13KXH1Zo=

https://www.mouser.com/ProductDetail/Nichicon/LKG1K222MESCBK/?qs=sGAEpiMZZMtZ1n0r9vR22d%2blFeYd%2bH4EXn8TOWKCHZw=


Here is a ring terminal you could use. Throw away the plastic and solder it to the snap terminal.
https://www.homedepot.com/p/Gardner...ing-Terminals-Yellow-15-Pack-15-107/202522877
 
Steven Tate said:
You're probably going to be looking at a cap with snap in terminals. You just have to solder ring terminals onto the snap in terminals. Lug terminal caps are getting harder to find. Nichicon Gold Tune caps are popular as audio grade filter caps. Here are two to look at. The 63v is 30mm in diameter and the 80v is 35mm. Check the existing one and see if one of them matches the diameter so it will fit the clamp.

https://www.mouser.com/ProductDetail/Nichicon/LKG1J222MESBBK/?qs=sGAEpiMZZMtZ1n0r9vR22d%2blFeYd%2bH4EbGD13KXH1Zo=

https://www.mouser.com/ProductDetail/Nichicon/LKG1K222MESCBK/?qs=sGAEpiMZZMtZ1n0r9vR22d%2blFeYd%2bH4EXn8TOWKCHZw=


Here is a ring terminal you could use. Throw away the plastic and solder it to the snap terminal.
https://www.homedepot.com/p/Gardner...ing-Terminals-Yellow-15-Pack-15-107/202522877
Click to expand...

Thanks Steven !
Is 1000 hrs a good life spec. ? Though I think link # 2 is a better bet, I couldn't find the hr. life.
 
I usually up the value of a 2200 uF because the new ones always seem to come in at the bottom of the spec. 2000 hours minimum, 5000 is better. 105c if you can get it, but I don't agonize over that much. Recievers just don't run very warm. These are available in several physical sizes, but there are probably a dozen different parts that would work great, including the ones above-
https://www.digikey.com/product-detail/en/nichicon/LGY1J272MELZ40/493-8677-ND/2540851
 
ConradH said:
I usually up the value of a 2200 uF because the new ones always seem to come in at the bottom of the spec. 2000 hours minimum, 5000 is better. 105c if you can get it, but I don't agonize over that much. Recievers just don't run very warm. These are available in several physical sizes, but there are probably a dozen different parts that would work great, including the ones above-
https://www.digikey.com/product-detail/en/nichicon/LGY1J272MELZ40/493-8677-ND/2540851
Click to expand...

Thanks Conrad ! I've got lots o' learning & comparing to do ! Great.
 
Question on capacitor life/hours: Does a capacitor start going bad or get weaker after the rated hours ?
 
SCOTTY#1 said:
Question on capacitor life/hours: Does a capacitor start going bad or get weaker after the rated hours ?
Click to expand...

The pessimists amongst us would say the cap starts going bad the minute you buy it, regardless of whether or not you install it in the circuit. In reality, those life numbers are for worst case conditions- high temperature and ripple currents. Think about a 1000 hour cap. That's only 6 months or so if run 40 hours a week under worst case conditions. In easy-peasy audio service, the part might work fine for 20-40 years. One tries to stack the odds in our favor by choosing high temperature (105C) and long life parts (>2000 hours), but it's probably no guarantee of anything. Regular use is important and if you have to use a lower spec standard part, you'll still get very long life.
 
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ConradH said:
The pessimists amongst us would say the cap starts going bad the minute you buy it, regardless of whether or not you install it in the circuit. In reality, those life numbers are for worst case conditions- high temperature and ripple currents. Think about a 1000 hour cap. That's only 6 months or so if run 40 hours a week under worst case conditions. In easy-peasy audio service, the part might work fine for 20-40 years. One tries to stack the odds in our favor by choosing high temperature (105C) and long life parts (>2000 hours), but it's probably no guarantee of anything. Regular use is important and if you have to use a lower spec standard part, you'll still get very long life.
Click to expand...

That's good to here. I was on Mousers site looking @ a can cap for the power board. It was the Nichicon Audio Grade LKG series. (2700uF,63v) The specs didn't list the life like I've seen on others. I contacted them & they told me 1000 hr life. So I thought, "On a good cap like that" ? I also sent them a pic to show them what I'd be replacing it with, stating I would be replacing all of them on the PB. They also said to stick with the uF due to changes on my board ? Can anybody make light of that ?
 
SCOTTY#1 said:
That's good to here. I was on Mousers site looking @ a can cap for the power board. It was the Nichicon Audio Grade LKG series. (2700uF,63v) The specs didn't list the life like I've seen on others. I contacted them & they told me 1000 hr life. So I thought, "On a good cap like that" ? I also sent them a pic to show them what I'd be replacing it with, stating I would be replacing all of them on the PB. They also said to stick with the uF due to changes on my board ? Can anybody make light of that ?
Click to expand...

No takers on this question ?
Does anyone have an idea why this wire got a little warm ? Thanks !
 

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