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Post by Admin on Feb 12, 2023 1:58:39 GMT
So, a friend was pitching an old Radio Shack 5 input portable audio mixer. Of course I said "I'll take that."
Fixed a couple problems and it works, except for the cueing. When cue is selected for any of the cueable inputs, the headphones go quiet. No cue audio for the selected channel(s).
Since none of the cueable channels go out the cue buss, I figure it's down stream near the final output to the headphones.
The mixer is an Archer 32-1101A. I've combed the internet, found several for sale but no user or service manuals.
In the mean time, I'll keep trying to trace the audio paths and see if I can locate the bad stage.
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Post by Admin on Feb 12, 2023 21:50:18 GMT
Well, the good news is I was able to determine why the cueing was not working and now it is.
Still, would be nice to have a service manual but not a priority.
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Post by station8 on Feb 13, 2023 13:57:14 GMT
Hi: I do have this unit and the original manual,But it's where I can't get to it at this time and my printer power supply is dead so I can't make a copy. But here is a schematic of 32-1200 series that should work. realistic_32_1200-a_stereo_mixer_sch.pdf (158.13 KB) Station 8 |
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Post by Admin on Feb 13, 2023 21:29:01 GMT
Thanks for that Jeff. I had found that one online and although it has some similarities there are a lot of differences.
But, it gave me a clue to how the cueing works and from that I was able to figure out what was going on.
The problem was external to the mixer. I didn't know the audio source I was using for testing had a MONO jack. That was putting a short to ground on one of the inputs. When the cue switch was set to cue, the audio was all dropping across the isolating resistors which are to combine the left/right channels sent to the cue buss.
Figuring that out, I got a different audio source (portable radios) which had a stereo out jack. Problem solved.
Another quirk of this mixer is the two mic inputs. Mic input 1 is marked "Left/Mono". The other is "Right". Plug into Mic 1 and it is assigned to the left and right outputs (mono.) Plug into Mic 2 and it's only assigned to the right channel and causes Mic 1 to be only on the left channel. Makes it a problem if you want both Mics in the center.
There is a separate "Mono"/"Stereo" switch but so far it doesn't seem to do anything, so I'll take a look at that next.
Not complaining since it was a cast off.
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Post by station8 on Feb 13, 2023 22:58:59 GMT
Hi Bob:
Good to hear that you got it figured out, I have gone through this before and also done reverse
Engineering and all I can say some time it's a Royal pain in the butt without the schematic & parts list!.
All I can say it sure keep you on your toes,But takes forever to do.
Station 8
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