Help reading capacitor

Question

I am attempting to repair a pcm and came across a cracked capacitor. However I can’t seem to decipher what the printed code represents for ordering a replacement. I understand the first line 474 being the Ferads .47uf or 470000pf. But I’m stuck on the 2nd and 3rd lines. It’s a board made by Motorola so I’m not sure if that’s a Motorola symbol or the tolerance. Can anyone chime in with what M 50, an 0 15 mean? Thanks.

shabaz · Accepted Answer

Great, that helps. They are plastic film caps.. harder to find nowadays, but ceramic caps could possibly work too. Here is the closest film cap replacement I can see currently: https://www.newark.com/kemet/r82ec3470dq70j/capacitor-polyester-film-0-47uf/dp/94M8815 Also it looks to be a size that should fit the space and height you have in the photo.

geralds · Answer

Hi, The capacitor looks like a Panasonic type ( [M] - logo), metallized polypropylen film. It has, its my interpretation momentary: 470nF, 50Voltage, Year 2000 (0), Week 15 (15); - also the other: Panasonic, 220nF, 50V, Year 2000, Week 24 But the marking code is an old coding system. https://industrial.panasonic.com/ww/downloads/catalog-download Changing from polyester to a ceramic type may help, but transients may damage an ceramic type faster than an self-healing polyester, or Polypropylen type. Search for an low inductive and low ESR type. Gerald ---

dougw · Answer

M50 sounds like the size (0.5 inches in length) 15 sounds like the voltage rating. But as Shabaz indicates a picture would make it easier to figure out.

lme14636 · Answer

It’s from a computer out of a mustang “Ford EEC IV” it was engineered with ford and Motorola. Most of the chips have the Motorola symbol is why I thought the circled M on the capacitor was a Motorola symbol. If I can figure out how to post more photos I will. Other codes on capacitors are 684 M 50 0 03, and 224 M 50 0 24.

dougw · Answer

The only manufacturer I've seen with M50 series capacitors is Cornell Dubilier: http://www.farnell.com/datasheets/1749226.pdf

royaljen · Answer

Hi Logan ,it seems that M50 is a code series of a motorola. My suggestion are do not bothered that code, very impotant when replacing a capacitor are the value rated. Replace it with the same value or close to. You may higher a little the voltage but to lower don't. You may find also a good quality capacitor from a reputable source. If it is electrolytic, Rubycon, nishicon are good.

lme14636 · Answer

Thank you for your help, since it was already cracked I split it open just now to add a photo of its internals if it would help determine if a ceramic would work.

shabaz · Answer

Hi Logan, Could you please attach a photo of the part (zoomed in, but also another photo zoomed-out for context, because sometimes the replacement depends on what the rest of the circuit is doing). It is unlikely to be a capacitor by Motorola, so the context is necessary to have a better chance to determine the replacement. Also if possible, can you briefly describe where the board came from (e.g. mobile phone).

shabaz · Answer

If it is an ECU, it is even more important to have photos of the part and area where the item is, to narrow down a replacement. I'm not aware of Motorola making capacitors, but maybe they did. Their semiconductors and main processor were likely in nearly every vehicle for some decades. The 50 could signify the voltage rating (it should be a lot higher than the nominal 12V battery voltage) but it would be good to see it. The first few digits do seem to indicate the value, based on the particular numbers you have mentioned. Since Motorola doesn't manufacture capacitors today, a different manufacturer replacement would be needed if they are faulty.

shabaz · Answer

Hi Logan, A ceramic might work, but in an automotive use-case there could be specific reasons for going with a different one - perhaps reliability or environmentals, I don't know unfortunately. It may be best to go for the film replacement, it appears to be for automotive use, and has the large temperature range. Hopefully it should outlive the vehicle if you go with that part.

Help reading capacitor

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