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Early MR-71 schematic

Hello all-

I have an early MR 71, or I assume it is, with the S/N 10B93, and the multiplex board and stereo/mono switching seem to differ from the drawings that I have seen posted.

For example, the multiplex output coupling capacitors are .1 Uf instead of the .02 uF listed, and the board layout and other component values differ. The opto coupler for stereo/mono switching goes to the multiplex board, rather than the cathode of the 12AU7 as well.

Does anyone have documentation for this version.

BTW, updating the coupling capacitors in the audio output section does make an audible difference, even to my tin ear. In this case, I used film and PIO capacitors-no electrolytics any more. The original 10 uF capacitors each measured about 20K ohms each.

Any help would be appreciated.

Regards,

TK41C


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Topic - Early MR-71 schematic - tk41c@aol.com 09:25:06 11/07/16 (0)

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