Does anyone have data on any of the Mac amps with meters in them? I have an MC420M here that I’m modifying, and I need the pinout of the plug that goes up to the meters from the main PCB. I’m thinking all the models are probably the same, so anything will probably get me close whether it’s a 431M, 443M or 440M.
The meters on this amp were both inop, so I’m installing OLED screens with ‘needles’ animated by Arduinos. If I get the info I need, I’ll post back a video of the final result for you all to enjoy.
The meters on this amp were both inop, so I’m installing OLED screens with ‘needles’ animated by Arduinos. If I get the info I need, I’ll post back a video of the final result for you all to enjoy.
Figured it out with a DMM and scope- pinout as follows, the plug is labeled with numbers so follow those:
1: ch1 audio
2: ch2 audio
3: +12vdc (constant)
4: chassis ground
5: +5vdc (switched)
6: ch3 audio
7: ch4 audio
8: PG LED positive
9: PG LED negative
When the amp is in 2-ch mode, the signal from the ch1 input gets sent to both the ch1 and ch2 meter pins, channel 2 RCA input is ignored. Same thing happens with channels 3 and 4.
1: ch1 audio
2: ch2 audio
3: +12vdc (constant)
4: chassis ground
5: +5vdc (switched)
6: ch3 audio
7: ch4 audio
8: PG LED positive
9: PG LED negative
When the amp is in 2-ch mode, the signal from the ch1 input gets sent to both the ch1 and ch2 meter pins, channel 2 RCA input is ignored. Same thing happens with channels 3 and 4.