Close inspection of the hardy outdoor IIci is warranted, because temperature cycling can induce cracks even in malleable metal such as solder. Then there is the effect of freeze-thaw cycling in caps with aqueous electrolyte. However, it may prove to be the large axial caps under the PSU, filter/smoothing caps in the PSU, and vertical aluminium electrolytics (as you found in the sound circuits) on the MLB that need most attention. Best of luck in your mission.

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