The capacitor issue dates back 10 years ago or so when a engineer from one Japanese capacitor maker left the company taking what he thought was their proprietary formula for the fluid in their electrolytic capacitors. He went to a different capacitor maker and they put the new secret formula into their production parts. The formula also spread to other vendors too. Unfortunately it was not the correct formula. It caused many capacitors using it to fail after 8-10 years of use. This caused an industry wide problem that affected many Japanese capacitor makers, manufacturers using these parts and many previously considered good reliable parts.
We unfortunately were the recipient of a batch of these tainted parts. They worked fine for many years, and we, along with other users of these parts, had no idea of the hidden issue until these parts started failing for us.
The failure mode is that when these electrolytic capacitors start leaking, the fluid leaking out corrodes and dissolves the nearby circuit traces, often ruining the circuit board completely. The issue can also be identified with a close inspection of the boards in circuit. The evidence is a trace of black goo along the lower edge of the board. We actually had to run a new batch of our obsolete Insight series preamp line boards just to be able to offer repairs for our clients. These parts were used on our basic line boards, our line - tone control boards, and our phono boards of that older vintage. They were not used on the power supply boards or in any other AVA products.
Minn Mark's preamp had these capacitors on his line - tone control board. Fortunately the problem was caught before the board was destroyed. Only one critical copper trace was damaged and we were able to clean the board, replace the trace with a jumper wire, install new capacitors, and restore like new performance.
We do have the parts available now to repair or replace any damaged boards caused by this issue. Since these units have provided excellent service for many years after the warranty expired, we don't consider this issue to be warranty related.
Frank