Electrolytic Capacitor Ratings in SAMS Photofact CB

[MindenJoe]

I'm looking to order replacement capacitors in my vintage radios I bought. I'm not sure how to read the rating column for the capacitor in the SAMS (1976) book. For instance, the capacitor for C140 lists in the book as a rating of 2200 25V. Now I understand the 25V, but not what the 2200 represents. When I look at the actual capacitor, it has an uF of 470. Why does the book not list the uF? Is there some formula to convert the 2200 to the uF of 470? My service manual for my Realistic TRC 465 lists the uF as well as the volts. Thanks for the help!

 

[press1280]

Not sure if yours was replaced with a 470 uf capacitor but 2200 uf is definitely a real capacitor rating. I'm thinking mine is bad (has the exact same rating as yours). Does it have 3 terminals by any chance?

 

[MindenJoe]

The capacitor has two terminals. I originally thought that 2200 might be the uF but that is not the case. If you look at the photo, the uF is 470, not 2200. I looked up another capacitor in the book. It states a rating of 220 16 volts. The capacitor on the board is 70uF 16 volts. I'm not sure what the first number represents in the chart in the book.

 

[GrayJeep]

Seems like you have the wrong SAMS or SAMS is wrong.

If the caps show no sign of being replaced I'd go with what you see on the actual physical device.

 

[MindenJoe]

I have three radios I'm going to work on and the charts are in the same format in each SAM book. I'm positive I have the correct books, and I'm sure that they have the original caps. One of the radios has not been used since the late 1970's so I know the caps weren't replaced in that particular radio. Like I said before, my later model TRC-465 lists the caps in a format I can understand. The TRC-465 service manual is not SAM.

 

[wtp]

try and get specs on the size of each to see if you can even get it in there.
kind of what the other guy said.

 

[kruser]

The manufacturer probably made some design changes After the SAMS book was printed.
That was very common back in those days.

And of course, errors are also likely figuring much was done by human eye and fingers on a typewriter!

 

[buddrousa]

As Stated above replace what you see in the radio.

 

[MUTNAV]

Is it possible that you are looking at c119 vs c140 , I used do things like that all of the time (as well as everyone else that worked on anything).

Thanks
Joel

 

[K4EET]

@MindenJoe, out of curiosity, what does the schematic show for the value?

 

[RFI-EMI-GUY]

Realistic TRC-465 - Electrolytic Capacitor Kit - Premium Kit | eBay

This upgrade will improve the function and reliability of these fine radios and extend their useful Life. Work slow, have fun and prepare to be impressed with your work. The Realistic TRC-465 Radios are excellent candidates for a Do It Yourself capacitor upgrade.

www.ebay.com

Here is a seller on e-bay selling capacitor kits for the TRC-465. Helpfully, he shows the values of what he is supplying. You might check this out.

By the way, I bought my TRC-465 in about 1994 and it was a recent model. I doubt you will find it in any SAMS publications from 1976. Great radio, should have kept it.

Caps can always be replaced with ones with slightly higher voltage and temperature rating. As far as capacitance values, they should be the same. Exceptions are DC filter caps. You can bump them up. Be careful with polarity. And soldering. You don't want to damage foil.

 

[MindenJoe]

Thanks RFI-EMI-GUY for the info. Luckily I found the service manual for the TRC-465 online. My second SAMS publication came in today for another radio I own and the caps specs matched what was in the book. It appears that the SAM issue I bought (100) is not the correct issue for my JC Penney model 981-6220 and that is why I was confused. I watched a YouTube video where a technician rebuilt the 981-6220 and since they didn't make a SAMS for that model, he used the SAMS for the 981-6235 which is suppose to be the same board. The board looked the same except for the caps. The cans and most of the other parts on the board looked identical. I bought the radio because I thought it was pretty unique and I wanted to add it to my collection.