by greg on Mon Nov 17, 2003 7:34 pm
11/17/03
Problem-
Neotek Series II talkback not reliable. apparently I didn't find the problem last time.
Solution-
12/5/03
I spent all this day with the console. I took the monitor, and master module out and triple checked the signal path (analog and logic) for the talkback. I managed to recreate the circuit on the bench. This way I could use all the gadgets. I measured all components involved, resoldered points, sprayed active parts with Freez-it to see if something was freaking out with the change in temp. Nothing was broken. I as I was testing it I found there was noise on the preamp send.. I replaced the transistor and op amp in the preamp- no happiness. I then recapped the circuit. The noise went away.
This is an example of how you find problems unnoticed before (us being the engineers would never hear the talkback signal, and the band probably doesn't care unless it is so loud they can't hear the engineer), and how they distract your attempt to find the big problem. I'll start referring to repairs to things no one complained about as a phantom fix. More about phantom fixes later.
I am hoping that the noise problem had something to do with our larger issue, but I'm skeptical.
The other avenue I took was looking at the wire jumper that carried the Cue 1+2, Echo 1+2, and stereo bus sends. This was the most promising looking point of possibility. A few wires were loose in their mounts. I repunched the wires at the molex plug, and checked the solder end.
If this doesn't work, I'll replace the FET switch and surrounding switching transistors (getting parts). Reinstalled modules. Again, we'll see if it screws up.
-Repaired a few cables
-AKG C-24
I installed the pattern select switch after testing it out a bit.
Put together the PSU and tested the patterns. They all work.
Last edited by
greg on Fri Sep 23, 2005 7:56 pm, edited 2 times in total.