Capacitor question for hardware gurus

[redrumloa]

I am finally getting around to repairing my old Televideo computer. I am making a Mouser order and looking at these old capacitor raises a question.

3300uF(M) - What does the M stand for?

Thanks in advance.

[rkauer]

 Means almost nothing! 3300 micro-farads means 3.3 mili-farads, but the last is not a current "measure".

 Only be sure to grab a 105 degrees type (high frequency type).

[LoadWB]

Red,

You sure that doesn't indicate the package type in their catalog?  Sometimes they show pics of different styles and label them alphabetically.

[koaftder]

UF/uF/µF/(M)/micro it's extra specific, don't worry about it

[amiga92570]

Might mean Mylar?

[koaftder]

Mylar caps:

[nBit7]

'M' may refer to the tolerance +-20% (which is about normal for electrolytic caps)
Or it may refer to a series.

105 degrees refers to max operating temperature.  The temperature before you kill the dielectric.  It has no relation to operating frequency.

The main parameter that decides the maximum operating frequency is the ESL (Equivalent Series Inductance) which is related to resonant frequency.  This information normally isn't provided for electrolytic caps as they usually not used for high frequency applications.

The parameter for more interest is ESR (Equivalent Series Resistance).  This is the main indicator of performance.  Generally Low ESR is better.  But higher performance brings higher inrush currents so sometimes it can be a bad thing.

Low ESR caps usually have some marking or bright colour (orange yellow) to identify them.

So if it looks like a fairly standard cap (blue or gray colour) replace it with a standard cap.

[redrumloa]

Thanks for the responses guys :-) One more question.

I loaded the order with General Purpose Electrolytic Capacitors. One thing I notice is the dimensions available are not exactly the same, all are a bit smaller. That isn't what worries me, I just would like to be sure general purpose is appropriate for the application. I am currently replacing the capacitors on 3 power supplies from this Televideo TS-801H computer.

There is no reason to need anything besides general purpose(20% tolerance) in simple power supplies, right?

Thanks again.

[redrumloa]

Ok here's a tough one!

Axial capacitor, 25V, 16uF, 85C. It's about 18mm wide, 40mm long. It has "SAMHWA" on it and "(M)8311". Finally the other side says "NPHF"

I cannot find this cap anywhere  :angry: Not Mouser, not Digikey, not ebay. I can't even find anything close. Any ideas?

[redrumloa]

Ah-ha!!! Is THIS it??


I think so, makes sense as it is on the monitor power supply.

Ordered, hope it is it.

[Stedy]

Redrumloa,

Try this part from Mouser, TVE1322
41.5 mm long (nominal).

Looks OK electrically to me, albeit a quick glance of the relevant specs.

Good luck,

Ian

[redrumloa]

Thank you, but that says 3300uF? This part is 16uF.

[nBit7]

Newer generation caps will be physically smaller don't worry.
General purpose caps should be fine for most power supplies.  High performance ones can in some cases cause problems due to higher inrush currents.

[nBit7]

Axial capacitor, 25V, 16uF, 85C. It's about 18mm wide, 40mm long. It has "SAMHWA" on it and "(M)8311". Finally the other side says "NPHF"

Axial are getting harder to get.  I am a little worried by the  "NPHF" the "NP" series of Samhwa cap is a non-polarised cap.
Maybe you should post a picture.  

[nBit7]

Ah-ha!!! Is THIS it??

Yes that should be fine.