828

The pictures I have uploaded were taken by me during the repair of a Motorola 828.  All three AF117 transistors, which are known to suffer internal faults commonly referred to as the 'tin whisker' problem, resulting in leaks or short-circuits between, e.g., the collector and screen, have been replaced with more modern equivalents.  I have also replaced the by now 50 year old electrolytic capacitors with modern types, using the nearest available capacitance values and working voltages wherever possible, althout the  main smoothing capacitor C109, originally 1000uf, has been replaced with a 2200uf, and C10 (200uf) with a 470uf.   Hopefully the pictures I've contributed, plus these notes, will be helpful to others servicing or restoring this series of radios.  The replacement transistors I used are Russian devices similar to AF127s, but with pin-outs identical to those of the AF139, which causes sompe problems when fitting them in place of AF117s, which I overcame in two cases, by mounting them 'upside down' and extending one or more of the leads.

Michael Goscombe † 1.8.20, 09.May.15

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I recently uploaded several photographs of the Motorola 828 together with comments and notes which I hoped would be helpful to other RM members, in the process pointing out that these radios are identical to the Radiomobile 970/980 series, and am wondering why this data has not yet appeared on the relevant pages.  The pictures were taken by me during a repair work I am undertaking on a Motorola 828, and include views of the Printed Circuit Boards, Tuner, etc., and,, as far as I am aware, do not infringe anyone's copyrights.  Are my photos & notes likely to appear soon?

Michael Goscombe † 1.8.20, 07.May.15

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