smelly power supply caps

[dharma one]

the caps on the PSU of our valve desk have started smelling, so it looks like time for a re-cap. a couple of questions - i haven't replaced them before, what safety precautions should i take, they are 40v caps. will letting them discharge for a day be enough? or should i actively discharge them? the transformer is huge too, and ive heard you can get quite a jolt from those..

secondly, how do i know which ones are the faulty ones? or do i need to replace all of them? there are 8 of them altogether

cheers :thumb:

 

[Viitalahde]

40 volt caps on a tube console? :?

Anyhow, you can de-charge them by making a probe out of a resistor and alligator clips.. wattage & resistance, no idea. :razz: Dinner time!

 

[Black Dog]

I use a 10K/2W resister to discharge the caps on my G9 as Jakob recommends on his website - works great :thumb:

 

[gyraf]

What valve desk is that?

 

[dharma one]

tlaudio vtc

 

[peterc]

This is the cct of the discharger I use:

http://1176neve.tripod.com/id29.html

I like it because when the neon goes out, the voltage is down to 60-70v which is fairly safe. I always let it drain down to 20v for my own piece of mind tho'.

Peter

 

[Svart]

? paralleled ecc83 with a ssm2017?

:shock:

hmm when i heard valve I expected more..

 

[Viitalahde]

Heh, that's exactly like SPL GoldMike. :green:

 

[AudioJohn]

The VTC power supply DOES have HT supplies - there are 470uF/350v and 100uF/200v capacitors on different voltage rails - so care DOES have to be taken.

There are, however, "bleeder" resistors across each capacitor - but still test with a meter to ensure the capacitors are discharged before working on the PSU - as it is common for these resistors to burn out - so cannot then fulfil their function!

It will cost you more - but do fit high quality capacitors, preferably 105 degree C types - as normal components seem to have a relatively short life in this PSU......