Cap temp ratings for the Duo?

[ProfessorProfessorson]

You know, this was not really on my mind at the time when I did cap replacements prior, so I did not bother to take note, but as of late with me doing so many cap repairs on different soundcards and motherboards and seeing lower temp caps in spots that should have used higher temp ones, I really got to wondering, what were the original rated temps for the through hole caps on the Duo? Was it 85 or 105C? I was thinking it was 85C, but I'm old and forgetful, so I could be wrong. Anyone remember or know what it was? And also, has anyone taken the time to quality check those caps to see if they held up before replacing them? Granted, they should be swapped out anyway due to age and work load, but was just curious if they actually held up as long as they were supposed to or if they just dried out?

[Tatsujin]

do you think the temp rating even matters for these caps? since they never go even near to that kind of operation temperature, unless you're obeying like 2000m underground.

[ProfessorProfessorson]

It can matter to a degree, depending on how well the cap was made to begin with, and how much heat that spot generates over a period of time.

[SignOfZeta]

Its never anything like 85C inside a Duo. Of course, I suppose the higher temp rating would be insurance.

[ProfessorProfessorson]

Well, the thing is, even if the through hole capes are only exposed to like a constant 50C, that still plays a factor in their total life cycle when factored in with the applied voltage to the cap and their rated load life. It's not one of those things where you cant just say they will last near forever just because one rated for 85C never actually reaches 85C.

http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx

That can kind of help you predict the actual service life time of the cap.

[NightWolve]

My Turbo Duo motherboard is sitting in a box, waiting for a full capacitor replacement and work on the S-Video/YPbPr Component mods, so I took a quick look for ya, and the labeled ones read 85 C. I misread you earlier, but then after rereading I realized, yeah, you were just asking about the traditional caps that are mostly used near the power regulators which do tell you the temperature rating (the compact, surface mount aluminum caps don't tell you, but I'd assume they're 85 C too.).

You're also in luck in that akaviolence did test old capacitors that he had removed from a Duo motherboard with his capacitance-measuring DMM for one of his videos. I linked it all proper to take you right into the video where he does the test cause that's how cool a guy I am.


First it's a 22uF capacitor that had visibly leaked and it reads just about 1.25uF with his DMM, so an obvious fail! The traditional ones he tests right after turn out to be somewhat OK actually. Anyway, for reference, I'm linking my other post about why one should get a good DMM like that with cap testing support! Very useful, not just for wondering how bad old caps are after you desolder them off, but checking how good the new ones are before you solder them on!!

[Game-Tech.US]

Yeah I rarely check any of the caps in the Duo anymore, they all need replaced whether they test ok or not.
I rarely see any of the leaded caps leak, but it HAS happened so be sure to replace them as well even if they look and test ok.
I'm not sure what anyone else is using, but I switched to Panasonic FR and FC caps a while back.
Both have low ESR and are high temp at 105C and are usually pretty cheap.
I've spent a lot of time over the years looking through Mouser's inventory for the cheapest components I need for projects so I know how to find the cheap stuff. I made a list of each and there was less than a $3 difference between a full set of cheap caps and a full set of Panasonic FR/FC caps!
BTW the FR line only goes down to 22uF so that's where the FC line comes in. I think higher uF FC caps had a slightly higher ESR than the FR stuff and also were sometimes not as cheap.
The badcaps forum has a thread recommending a bunch of different manufacturers and lines of each. Panasonic FC and FM are on the list, FR is not, but the post has not been updated in 3 years. Mouser didn't have a lot of FM stuff and what was there was higher cost than FC and FR stuff.
Mouser has a 'share project' feature so i'm going to add that LINK.
That should be a list of each cap I chose with correct quantity needed for a full cap job, total of $6.10.
Let me know if it works.