[sdiy] Reasonable cap replacement policy

Nathan Trites nathan at idmclassics.net
Fri Feb 7 17:27:23 CET 2020

I'm also in the "if it's not broke, don't fix it" camp. Occasionally I'll
do the caps in a PSU but if everything else is functioning reliably it's
overkill to recap a whole device.

However, I have replaced a good number of failed caps in early 00s
equipment, and to a lesser extent on older gear. Around 2010, a company I
worked for was getting amplifiers made around 2000-2005 sent back on a
regular basis and the preamps usually had caps that leaked or exploded, so
I've probably replaced 100+ in the years working there.

The "capacitor plague" is well documented and affected plenty of industries
using contract manufacturers for board assembly, anyone doing repair should
be aware of this: https://en.wikipedia.org/wiki/Capacitor_plague


On Fri, Feb 7, 2020 at 8:18 AM Pete Hartman <pete.hartman at gmail.com> wrote:

> Gordon, you say this every time I see you commenting on this topic even
> though several of us have pointed out that we *have* seen failed electros
> in synths and other gear--and not just in psus.
> Do you really think your individual experience is that much more typical
> than the rest of us?
> I agree with the idea that blind "re capping" is a foolish shotgun
> approach, and you're right that it often goes hand in hand with
> inexperience and bad work, but that doesn't mean electros don't fail or
> that they shouldn't be checked out.  Bulges and leakage do happen and do
> indicate that the caps showing such signs need to be replaced.
> Pete
> On Fri, Feb 7, 2020 at 4:50 AM Gordonjcp <gordonjcp at gjcp.net> wrote:
>> On Thu, Feb 06, 2020 at 10:14:12AM -0800, John Speth via Synth-diy wrote:
>> > Hi folks-
>> >
>> > Today I called a shop about replacing the belts on my 30 year old
>> > cassette tape deck (Fostex X-26). The guy quickly recommended also
>> > replacing the caps (I assume just the electrolytics). I'm guarded
>> > against folks who do repairs on stuff that don't show signs of need,
>> > which my tape deck doesn't.
>> >
>> > What are the prevailing opinions on replacing old electrolytics in
>> > equipment from the 1980's?
>> I have pretty much never seen a failed electrolytic in audio equipment,
>> leaving aside cheap shitty switched-mode power supplies.  I've seen a
>> lot of leaky disc ceramics, but weirly mostly in radio gear.
>> If someone brings me a bit of kit that's been "re-capped" to repair -
>> because it's never "bad caps" - it's 300 quid for me to even take the
>> screws out because I know it'll be a total shitemare from start to
>> finish.
>> --
>> Gordonjcp
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