Filter capacitors in Toshiba SC-335 power amp

[62vauxhall]

I was unsure if the Parts forum would be more appropriate but since this may be a general question, I thought Solid State might be the best spot.

I've posted previously about a Toshiba SC-335. Now finding myself in possession of a second one, I am in the process of replacing it's electrolytic capacitors and some suggested transistors as I did in the first.

Those amps have 50 volt 10,000uF filter caps and I used 63 volt 10,000mF as replacements. Since the new caps were physically smaller than the originals, I extracted the insides out of the old ones and dropped the new ones inside the cans. I did this because they are fixed to the chassis with a metal clamp and the new capacitors were of too small a diameter. Doing this was a bit involved but it worked.

So my present question - is it even necessary to replace those capacitors?

I ask this because the internals of the old capacitors looked fine and not dried out. Is this a useless observation? I have no dedicated capacitor checker nor any other test equipment other that a fairly basic DMM.

 

[JonSnell Electronic]

You need to measure the ESR and capacitance of the old capacitors and determine if they are within specification. Most capacitors are replaced even though they are fine. Transistors fail but do not require replacing until they do.

 

[Karl vd Berg]

...

So my present question - is it even necessary to replace those capacitors?

I ask this because the internals of the old capacitors looked fine and not dried out. Is this a useless observation? I have no dedicated capacitor checker nor any other test equipment other that a fairly basic DMM.

What JonSnell said. Check ESR and capacitance before replacing the big caps in the PSU.

I have the SC-530 model. Its big 12,000uF caps are still under specs (measured ~ 12,300uF) and their ESR are around the same value of a newer 15,000uF that I have here, so I'll probably leave the 12,000uF in place.

What you can do in your SC-335 unit is replace the smaller ones, like C3 and C4 with a fresh new 10uF/35V; C5 and C6 also replace with new, but of 16V or 25V voltage rates and C19, C20, C21 and C22 can be replace with new caps of 63V... And the relay, too.