PROJECT/one Mark IV A Receiver

MCS Guy

The MCS hoarder
I got this one off ebay for a price of 7.99. It would power on, but no sound from both channels. Ended up that the right channel outputs were shorted.

With help from an AK member, I was able to get some ON semi MJ21193/MJ21194 output transistors and put them in Yesterday. The outputs, heat sinks, and driver boards are easily removed by 2 screws. The Driver boards are socketed to the Protection/PS board below it. Changing outputs on this receiver is a walk in the park. She came alive and sounding pretty sweet. Spent today cleaning the controls and faceplate. Blew out the dust and waxed the transformer.

The receiver seems to be about 40-50 watts RMS (45 volt Rails) with 2-10,000mfd Caps in the power supply. The tuner is a 4 gang/3 gang setup and pulls in stations with ease. The receiver has 3 sets of speaker terminals and Pre and Main jumpers.

Very nice looking receiver. The signal meters remind me of marantz for some reason
 
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Same white painted traces as the Mark 1500... Wonder who did these for them? Any identifiers in there anywhere? The Mark 1500s are completely void of anything to positively identify it. Looks to me they are either Pioneer or Hitachi made. Designs share some similarities with each (perhaps on purpose?).
 
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