Hi group. If I have posted this question amiss, or if it is not appropriatefor the forum, please advise. I am a novice in the electrical field. Thank you.

I am changing a capacitor in an AM radio from a 57 Fird Pickup. The cap was made by Bendix and is # L220353-4.
It appears to have one (-) and 2 (+) and 2 additional mounting legs.

I watched a tutorial where it was replaced by (2) modern caps achieving the same outcome, but not utilizing the (2) mounting legs of the original capacitor.

Im trying to determine what those (2) modern caps are so I can procure and install them, or if a suitable substitute exists.

Here are some photos. A couple are from the tutorial.

I hope Im not being too vague.
Thank you

 

Hi h71,
The new caps are 250uF at 16VDC.
The old cap 2 mounting legs are at 0V/Common and need not have a component inserted.
You could get an original cap from this link.
E
https://www.ebay.com/itm/115216850609

 

Thank you ericgibbs.

I saw those caps on ebay also.

I think that I read somewhere that the issue with those caps is that age is the enemy. They are supposedly oil or paper tyoe and have a purpensady to dry out over time.

The capacitor in my radio is old, but the cap on ebay might be almost as old although never installed.

 

Thank you ericgibbs.

I saw those caps on ebay also.

I think that I read somewhere that the issue with those caps is that age is the enemy. They are supposedly oil or paper tyoe and have a purpensady to dry out over time.

The capacitor in my radio is old, but the cap on ebay might be almost as old although never installed.

Old stock is certainly a possibility, and the newer caps are probably a better choice. As for the unused mounting tab locations, some times they also served to provide connections to other PCB traces. So I suggest tying all three mounting tab holes together just in case. But avoid causing any shorted circuits.

 

Does this new ebay capacitor look like a good substitute for these old Bendix 200vdc .1mfd capacitors?
BENDIX c220098-8

 

Capacitors age with time. Why not buy new modern caps?

 

I don’t replace capacitors unless I know they need to be replaced.

 

Given that we can not see any of the markings on that "EBAY" capacitor there is no clue if it is a good choice or not. Some brands are bad news, others are quite suitable.

 

Thank you

 

I apologize for being so vague.

The old caps in the picture above are 'outside foil' wax caps.

They are 200 volts WVDC and .1 MFD.

The cap in the photo from eBay (above) appears to be a similar capacitor so I am wondering if it would be a good replacement.

Also, is that old wax capacitor electrolytic? or can it be installed either way?
Thank you

 

Hi John.
I would advise that you buy modern type capacitors of the same value capacitance and voltage.
E

 

Thank you all.

 

I don't buy capacitors (or any electronics components) from ebay.
My suppliers are Digikey, Mouser, or Newark.

Buy two 270μF/25V radial electrolytics:
https://www.digikey.com/en/products/detail/nichicon/UPJ1E271MPD/2599139

For 0.1μF/250V axial
https://www.digikey.com/en/products...draloric-bc-components/MKT1813410255G/5378365

 

The non-polarized capacitors, like the wax coated ones, can be installed either way with no problems. The original concept was that when they were used as BYPASS capacitors, with one side tied to chassis "ground", that the outside foil would serve as a shield to keep external electrical noise out of the circuit being bypassed. Quite an interesting idea, but how much it ever mattered I don't know. BUT that is the explanation for why the outside foil connection was marked.

 

Can you help me undetstand something that is puzzling me tonight?
My original capacitor says 250 MFD, but the one suggested says 250 uf.
Some places I have read that MFD and uf mean exactly the same thing, but seems like just as many say otherwise.

There seems to be a 1000 times difference between micro and mili.

How should I understand this?
Thank you,
John

 

Some folks choose to use that symbol for the word "MIcro", while others of us do not have that symbol conveniently in our font file. Then also there is the confusing misuse of "mil" for "thousand" or "thousandth".
With capacitors there is, fortunately also the fact of relative size. A "250 uf. "=250 microfarad capacitor will be a larger physical size, and most often be polarized as well. And the really good news is that "micromicro" has now generally been replaced by "pico", as in "picofarads" a much smaller unit of capacitance, and always a physically much smaller capacitor.

 

My original capacitor says 250 MFD, but the one suggested says 250 uf.

Hi John,
Use the 250uF capacitor, the MFD is a very old method of marking.
E

 

Thank you.

 

Know the difference
250MFD = 250 μF = 0.25 mF

 

Hi John,
Use the 250uF capacitor, the MFD is a very old method of marking.
E

Understand that "uF" is the symbolic way to write "Micro" and it was not always common in pre-computer font files. The meanings are identical.