about 6 mos ago i refurbished this set new caps and siilca throughout. as its not a very popular unit (and mine was made in oct,'69) i couldnt find a recap list or a transistor substitution list i had to piece one together from threads that offered substitutions as part of repairs,it was a lot time on the computer but well worth it as it sounds really nice. INITIALLY i had a problem with the stereo lite and it was in mono all the time. my skills are limited i replaced the i,c. on the mpx to no avail. i read that the original w13-024 mpx was problematic so i opted for a flea bay solution a w13-026 which was pioneers answer in later production runs. i recapped it and re transistored it and installed it and it was an immediate success, separation and a functioning stereo "ON" light. this lasted for some weeks until i went to change the channel and saw that the stereo light SOMETIMES will stay on ALL the time even when switching between phono and am in fact in all modes SOMETIMES! other times it behaves normally. if it decides to act up it will do it initially but after it plays for an hour or so straightens itself out. i used automotive 6 v leds for the indicators which i half wave rectified with a 1n4004 in the 7.5v supply ive no trouble with that setup but it has "EATEN" two of the same leds used in the stereo "on" light position. the light doesnt flicker much unless the signal drops below the first bar on the meter which i THINK is normal as it squares with my other pioneers. today it was on all day in my shop and worked fine i went to shut it off and as i moved it off station the light went off and on as it should, i moved the mode switch to phono and aux it flickered and stayed on in all modes and would not go off when moved off station in fm stereo!!! anyone have any theory's???