Help with replacing Capacitors on Altec Lansing ATP 3

[yuzupatogik]

Hello,
I have this old (2004?) Altec Lansing ATP3 and i would like to replace the capacitors. I have identified 34 out of the 36 of them as Samxon GR of various capacities and voltages.

I can't find datasheets for the Samxon in any of the following variants:

10000uF 25 v - this one i really want to replace because i suspect it is what causes a dull hum regardless of the volume knob position or if the source is plugged in. I am eyeballing the Rubycon 25PK10000MEFCGC18X35.5 for this purpose. So if i pay a 10x the price part for shipping i might as well go ahead and order some to replace the rest.
10uF 25V
100uF 25 V
1uF 50V
0.47uF 50V
2,2 uF 50V
0,1 uF 50V
4,7 uF 50V
47uF 16V
470uF 16V
0.68uF 50V

Now, can i just replace them with some Nichicon UFG/Rubycon/Panasonic FR/FM? If so, what Series?
If anything, could you please provide some generic tips like ripple current, ESR ballpark values?

Thank you!

[momaka]

Judging by the rather big capacity of that 10000 uF bulk filter cap, it looks like this system uses a linear (line-connected) AC transformer... so none of the caps have to be low-ESR / low impedance, or anything special. Just get quality Japanese-made 85C or 105C caps, and all should be OK. That said, I find that some low-ESR series are usually cheaper than the general purpose 85C or 105C parts. In cases like that, you can go with the low-ESR series. But I wouldn't bother looking at datasheets for this kind of application. So long as you stick with the known good Japanese brands (Rubycon, Panasonic, Nichicon, and United Chemicon), you shouldn't have to do this type of repair for at least a 2-3 more decades.

Now, if you really want to go "all-out" on this, some of the pre-amp circuits in this unit might behave "better" with audio-grade caps - particularly with small caps in the signal path, as audio-grade caps tend to have lower leakage current and thus should be less noisy/hissy (in theory anyways!) I personally don't think one would be able to notice any appreciable change in sound with these IC-based audio systems, so I tend to use whatever caps are the cheapest usually (but good quality brands, nonetheless.)

That being said, I don't know if new caps will cure the line hum, if it's very very faint. At least from my own Altec Lansing VS-4142, it appears that the slight hum is due to poor PCB routing design. But if you have more-than-subtle line hum, then most likely either the big cap or any "ripple filter" caps for any of the power amps might be going bad. Another thing that could cause hum are poor solder connections, especially on an old system like this that's been through a lot of use... so give all the solder joints a thorough check. Any resistors that run hot are most likely to be affected... though I don't really see any on your board (for once a not-so-terrible design, I suppose ).

Anyways, have fun recapping and let us know how it goes.

*edit*
By the way, for the 0.1 and 0.47 uF electrolytic caps, consider replacing them with metal film polypropylene type capacitors. These are generally considered better for audio-signal circuits (but again, I can't say if it would be worth it on a system like this.)