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How do you buy capacitors?

Tony L

Tony L

Administrator
Dumb ass question time I know, but where do you go to buy capacitors? The star of my forthcoming retro system has turned up, a lovely Marantz 2252b receiver, and as it is at least 25 years old I’d like to replace some of the more obvious bits. The two main PSU caps are 50v 10,000uf and about 35-38mm wide (hard to measure exactly without ripping them out). I’ve had a look on both Maplin and RS, and neither seem to have 50v caps, and neither seem to specify size. Any ideas?

Another question: How do you tell something like a cap is genuinely needs replacement, i.e. how do you measure it? The only ones I've ever replaced before were in guitar amps and I only knew to replace them because they had leaked. No such clues in the Marantz thankfully.

I’ve got the service manual for the Marantz, and I followed the procedure for setting up the power amp and a couple of the things I’m able to test myself were very slightly out of spec but I’ve tweaked them back with the trim pots (amp board voltage and DC offset). I know bugger all about electronics, but quite fancy having a go at restoring this monster myself.

Tony.
 
"Dumb ass question time I know..."

Yes, but you're the boss so nobody will take the piss :p

"The two main PSU caps are 50v 10,000uf and about 35-38mm wide (hard to measure exactly without ripping them out). I’ve had a look on both Maplin and RS, and neither seem to have 50v caps, and neither seem to specify size. Any ideas?"

Go for a higher rated (63V) cap. You need to register with RS (anyone can) before you can view specifications on components. I recommend BHC caps - they come in different versions depending on how they are to be mounted. (PCB/solder tags/screw term's etc). ALS30 and ALS40 spring to mind.

"Another question: How do you tell something like a cap is genuinely needs replacement, i.e. how do you measure it? "

Electrolytic cap's start to go downhill as soon as they leave the production line. 25 years without spilling their guts is pretty good, they are well knackered by this stage.

"I know bugger all about electronics, but quite fancy having a go at restoring this monster myself."

Stand by for a barrage of conflicting advice :)

Good luck.

Mr Tibbs
 
Tony,

I second Mr Tibbs' advice; BHC Aerovox are always a safe bet. There won't be any sonic disadvantages from using higher voltage caps IME; also gives you also a better safety margin.

If you need to replace smaller caps that are not in the signal path, I would go for Panasonic FCs (also RS), I have used them in two DIY projects by now and just cannot find anything to complain. ;)

I trust you already have a multimeter?

Best regards,

Oliver
 
The important thing is to wire electrolytic caps the right way round. If you get it wrong they can explode! They are clearly marked so it isn't too difficult provided you make a note of the original orientation.
 
Marantz 2252b:cool:
Nice piece of kit Tony!
Remember that caps are usually smaller now than the older types so hopefully 63v ones should be ok regarding width although may be taller.
I've never had one of these beasts but a friend used to own one:)
 
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