| Electronics > Beginners |
| Help with replacement capacitor shopping |
| << < (3/3) |
| Electro Detective:
A 27 year old device more than likely has decent quality standard capacitors in it. Having learned the hard way a few times, I would avoid the 'buy better' mindset and get exactly the same values and voltage ratings and 85 degree ones if that's what was in there, as the last lot lasted years and years... Buy reputable brand caps and you're set :-+ If the caps are near heat sources, get 105 degree rated ones with closely similar specs to the 85 jobs I'm assuming you don't want to play upgrade mod engineer |O :-[ and just want that device rocking 'day one' again asap, right? :-// |
| t1d:
--- Quote from: Electro Detective on May 31, 2019, 11:06:24 am --- A 27 year old device more than likely has decent quality standard capacitors in it. Having learned the hard way a few times, I would avoid the 'buy better' mindset and get exactly the same values and voltage ratings and 85 degree ones if that's what was in there, as the last lot lasted years and years... Buy reputable brand caps and you're set :-+ If the caps are near heat sources, get 105 degree rated ones with closely similar specs to the 85 jobs I'm assuming you don't want to play upgrade mod engineer |O :-[ and just want that device rocking 'day one' again asap, right? :-// --- End quote --- Thanks for your help, Electro Detective... Yours is good advice and I know the reasons why. I just completed my order at Mouser. I try to stick to Nichicon and Panasonic, but for one item I had to stray, because it just wasn't available... The original is Illinois Capacitor and that is what I ended up with as its replacement. The big mains caps are dead on for all specs, except their height is lower, due to better cap technology. And, I bought a high ripple rating. 2.6a, IIRC, the original being unknown. The other caps are dead on for uFs and pin spacing. Diameter and height are what can be accommodated. Voltage was allowed to vary upward. My thinking was that inrush was more important for the big supply caps and not so much for the other caps. Let's hope I don't fry an op amp, or such... And I bought high ripple ratings. Hours, too. Because of the nature of the job requires better quality and there are just a few caps, meaning it can't add up to much, I did not skimp on quality. Total OTD was about $21USD for 13 caps. If you think I can get in trouble on the inrush current, please let me know. I appreciate everyone's input. P.S. I am thinking of doing a repair thread, when the parts arrive. |
| Electro Detective:
Hey, no shortage of repair thread junkies here (guilty as charged :-[) FWIW I've got four identical suss power supplies to dig into soon, and know that one of them has the original caps that lasted many many years, and finally clapped out, causing audio hum. whereas the other three were recently re-capped, apparently with 'good enough' and or 'better' caps, and already in a short while producing audio hum. Two were spares that were used a few times and sat on a shelf, seems like the caps thought they were batteries and died anyway :horse: So...the plan is to work out which of the four has the original cap work, sort of try to replicate what was fitted at the factory, verify that all is good using quality pre-tested caps. then do the other three if it's a go, which I'm confident it will be, been there before :phew: |
| paul8f:
Great advice in the replies to this one! I'd agree with aiming to keep as close as possible to the original component specs. If unsure, aim for a low-ESR rating, 105deg temp rating and obviously no lower than the original max working-voltage. Before installing the replacements, test the new caps with a quality meter such as the Peak Atlas ESR70 (just because a component is new and shiny doesn't mean you didn't get shipped a dud! |O) If you need to bend the legs to align with PCB holes, then after soldering support the new cap with a dab of hot-glue or Silastic compound. Also after soldering, don't forget the basics like using flux remover to clean the flux off, and also making sure that the new cap has the same orientation as the one removed (don't rely totally on PCB markings denoting the NEG side... on very rare occasions the silkscreen/soldermask symbol is incorrect...yes I've seen this firsthand.) As a side note... in my collection I have yellow Nitai non-polarised (bipolar) 100uF electrolytic capacitors, so just remember these do exist. Good luck with the repair :-+ |
| Electro Detective:
--- Quote from: 3roomlab on June 01, 2019, 07:37:03 am --- before you hit that buy button because it is a cheap 105C rated 5khrs etc etc, make sure to measure the size that it fits. all those damn sites have huge "add to cart" buttons but most crucial size data are right way way at beyond screen view :-DD --- End quote --- Yeah, no physical dimensions :-// = no Buy button click, dump the shopping cart, and the Finger at the checkout robot >:( ;D |
| Navigation |
| Message Index |
| Previous page |