Dumont RA-108 ETF2009 Auction Score

[jshorva65]

Thanks to all of the posters of congratulations!

Pre-Emerson Dumonts have always seemed to be exceptionally well designed with reasonably roomy under-chassis layouts, so this set was reasonably easy to get going except for that issue with the bad NOS oscillator transformer. I ended up re-stuffing the two 80uF/350V main B+ filters and replacing most of the axial electrolyticslytics. Five of the six twist-lock cans tested as OK, but I re-stuffed BOTH of the 80uF/350V units since the two of them are wired in series to form a 40uF net capacitance at a higher working voltage. Both were reasonably easy to reach, so it made sense to re-stuff both while I was at it. All sections of the remaining "cans" re-formed to reasonable leakage values at test voltages 20% above rated VDC. With acceptable leakage at a "surge" test voltage equal to 120% of rated working voltage and ESR under 0.5 ohm, that's a "comfort zone" for me. The main reason for replacing some of the axial electrolytics that I replaced was due to their being strapped to the chassis and needing to be removed to replace paper/wax units "hiding" behind them, anyway.