MH Conversion Reg Audio II board question

Robochronic

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Picked up a nonworking Tempest conversion and noticed the resistor at r29 was burnt- swapped in a working board and got smoke right away. Guessing I need to check or replace the ps brick next. Never worked on power supplies. Can anyone advise on next steps? Should I swap in a working brick (I recall the outputs may be different for MH than tempest or space duel). Any help appreciated. Thanks.
 
Sounds more like you have a short or bad connection on the tempest MPU board. R29 is used for the "intelligent" circuitry of the ARII boards that regulate the +5v. +5v is sent to the MPU board. To make sure the board is getting the proper +5v, the voltage is sent back to the ARII board via the +sense line. If you have a 1) bad connection, B) broken wire, Tre) dirty/corroded edge connector, or 4) missing +5v on the main board itself, the "intelligent" circuitry on the ARII will try to compensate by upping the current there by burning out the R29.
 
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