Capacitor plague

High failure rates occurred in many well-known brands of electronics, and were particularly evident in motherboards, video cards, and power supplies of personal computers.

[3] The first flawed capacitors linked to Taiwanese raw material problems were reported by the specialist magazine Passive Component Industry in September 2002.

[1] Shortly thereafter, two mainstream electronics journals reported the discovery of widespread prematurely failing capacitors, from Taiwanese manufacturers, in motherboards.

[6] The news from the Holzman publication spread quickly on the Internet and in newspapers, partly due to the spectacular images of the failures – bulging or burst capacitors, expelled sealing rubber and leaking electrolyte on countless circuit boards.

[5][7][8] The quick spread of the news also resulted in many misinformed users and blogs posting pictures of capacitors that had failed due to reasons other than faulty electrolyte.

[2] Major vendors of motherboards such as Abit,[10] IBM,[1] Dell,[11] Apple, HP, and Intel[12] were affected by capacitors with faulty electrolytes.

The normal lifespan of a non-solid electrolytic capacitor of consumer quality, typically rated at 2000 h/85 °C and operating at 40 °C, is roughly 6 years.

Since the electrical characteristics of electrolytic capacitors are the reason for their use, these parameters must be tested with instruments to definitively decide if the devices have failed.

However, independent laboratory analysis of defective capacitors has shown that many of the premature failures appear to be associated with high water content and missing inhibitors in the electrolyte, as described below.

To protect the metallic aluminium against the aggressiveness of the water, some phosphate compounds, known as inhibitors or passivators, can be used to produce long-term stable capacitors with high-aqueous electrolytes.

The results of chemical analysis were confirmed by measuring electrical capacitance and leakage current in a long-term test lasting 56 days.

Due to the chemical corrosion, the oxide layer of these capacitors had been weakened, so after a short time the capacitance and the leakage current increased briefly, before dropping abruptly when gas pressure opened the vent.

Their further conclusion, that the electrolyte with its alkaline pH value had the fatal flaw of a continual buildup of hydroxide without its being converted into the stable oxide, was verified on the surface of the anode foil both photographically and with an EDX-fingerprint analysis of the chemical components.