Heathkit GR-900 Build Thread!

[N2IXK]

The GR-900 build continues..

Next up, the luminance module. This module incorporates the standard luminance circuitry found in any color set, in addition to the dot generator circuitry used for the convergence setup. The dot pulse generator circuitry incorporates a relaxation oscillator based on an NE-2 neon lamp, followed by some wave shaping circuitry.

Testing a sample of the original electrolytics showed that most of them were acceptable, but a few showed borderline high ESR, even after reforming for a few hours at or near rated voltage. I decided to replace all the small electrolytics as cheap insurance against problems. The 2 large twistlocks for the main chassis seemed to reform perfectly well, and will be used. Replacing the electrolytics on the smaller modules allowed me to get radial lead types where needed, rather than the rather ugly vertical mounting of axial caps that the board layout originally called for.

Next up--the Video Output board.