[sdiy] Old Component Breakdown

Grant Richter grichter at asapnet.net
Mon Jun 24 18:17:25 CEST 2002

>From practical repair experience for synthesizers of all types, the list is
arranged in order of most common occurrence:

1. Mechanical damage including being dropped (most common), Coca-Cola or
other spills, oxidation, or in one case, an moth caught between the NC
contacts of a headphone jack preventing the speaker from working (literal

2. Failure of a component due to lack of routine maintenance (lithium backup
batteries or keyboard contact cleaning).

3. Failure of the power supply due to heat, or reversal of power supply
leads causing catastrophic failure. Repairing and calibrating the power
supply will sometimes bring the whole synth back into calibration.

4. Electrolytic capacitor failure due to age.

5. OTA failure (OTAs seem to be relatively fragile devices, it is a good
idea to socket them in most applications).

6. Failure of early integrated circuits from impurities introduced by
limited process controls. Modern integrated circuits are much more reliable
than those from 30-40 years ago, due to vastly improved process controls
during manufacturing.

7. Anything else and secondary failures caused by one of the above reasons.

> From: "Lewis Bupp" <lbuppii at hotmail.com>
> Date: Mon, 24 Jun 2002 07:17:13 -0400
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Old Component Breakdown
> I just replaced the capacitor on the Sine output on my Paia 4720 VCO. In
> thinking about this I was wondering how long components last and when they
> should be replaced. Any of you guys have a any ideas on this? Resistors are
> pretty hearty and normally don't break down. But what is the lifespan ( in
> years) of Caps ( all types), Diodes, Opamps, Pots, etc. ?
> Any ideas?
> Lew
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