I'd like to throw my hat into the ring.
All of what has been said above is true. If a piece of "vintage gear" "aint broke" there's no need to fix it. Ceramics and Tants are notorious for giving problems as they age. Tants simply give up the ghost and go bang, no warning, no drifting values. Ceramics will begin to drift from there stated value till they simply become resistive. Here's an example, I received a Drumulator that suddenly refused to power up. The start up is triggered by a voltage sensing arrangement that requires the 5v line to be at 5v and stable. I measured all the PSU voltages and all was good except the 5v line., it was only at 3.94 v. I lifted the output leg from the board and found it to now be a stable 5.0v. The Drumulator is chock full of TTL logic and as such each chip has a 0.01uf ceramic cap associated. I removed ALL said ceramics and replaced with new. Problem solved, nice running Drumulator. Overall the vast number of leaky ceramics had become a resistive load, dragging the 5.0v line down.
As to Electrolytics, I agree, replace only if they show signs of fault. BUT if I am undertaking a full restoration of a piece of gear and wish to return it to it's original spec, every component gets a full "once over" and replaced if a even suspect it's not to spec.
If I did not do this, it would be akin to restoring a classic vehicle but not rebuilding the engine....doesn't make sense.
With this in mind though, restoration work carried out by someone not experienced in the field will certainly create more problems than what it was worth.
"Simply cutting down the weeds with a lawn mower may remove the immediate problem, but the weeds WILL grow back"
cheers
Richard
--- In Simmons_Drums@yahoogroups.com, "gordonjcp" <gordon@...> wrote:
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> --- In Simmons_Drums@yahoogroups.com, Jacquot.Patrice@ wrote:
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> > What about when the condensators are dead or progressively faulty ?
> > don't they involve other componants damages & breakdowns by not regulating anymore tensions ?
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> That's a bit of a myth. If you run gear in seriously hot conditions more-or-less continuously you will eventually start to dry out the electrolytic capacitors. This will make the supply voltage drop and go all ripply, and you'll hear that as a hum on the output. Other than that, they just don't seem to fail, much.
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> Disc ceramic capacitors fail by going leaky - that is, the ceramic stops being an insulator and they slowly become resistors. This happens quite a lot - in one particular kind of radio I work on, I often change three surface-mount ceramic capacitors because if they haven't failed yet, they will soon. Once they start to go leaky the decline is rapid - before long they will become a dead short and cause all sorts of mayhem.
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> Tantalum bead capacitors which are used in computer equipment to decouple noise from power supplies fail by going dead short ∗instantly∗. You know when this happens because of the thick smoke and horrible smell. In an emergency you can often just cut them off the board until you get a chance to replace them. It might be noisier, but it won't break anything.
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> Gordon MM0YEQ
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