Quote:
Originally Posted by bgadow
Mine looks something like the one Red Raster pictured-ugly, but working. I'd very much like to try this upgrade.
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We're going for the maximum ease of maintenance and neatest appearance we can achieve, experimenting with mounting the fusible-link array using turret pins on perfboard and selecting the resistive elements in our design with a precisely-determined safety margin to provide cool and reliable operation while conserving space inside the enclosure. The Rectification version has proven to be the most compact, but the Reactance version only requires a single thermistor to provide adequate inrush limiting. Although we have found that the Reactance circuit paired with thermistors resulted in startup current barely rising above normal operating current, the additional space consumed by two additional thermistors resulted in an excessively tight fit of the assembly within the enclosure. The reduction in startup current derived from the Reactance approach alone seems quite adequate.
The fusible-link protection also minimizes the potential for damage to the set as a result of excessively leaky heater bypass capacitor or severe H-K leakage in one of the tubes near the upper end of one of the heater branch circuits. Basically, an open fusible-link on one of the heater branches is intended to function as a guide in troubleshooting which would indicate the strong possibility of some underlying cause existing within the circuitry of the set itself.