Signal not coming to VCA fader

[oyanliz]

Hi all,

I had a channel which sometimes stoped sounding when mixing, but we use to move the channel fader to the top and the sound came back usually. This channel stopped sounding yesterday.
The upper and lower cards of the module are ok, the VCA fader is ok (we have tried with another channel and it works everything fine), we have swapped all the cards one by one, 82E291 (amp), 82E13 (VCA), 82E294 (group amp) and logic card, without success. When signal is injected into the channel, there is signal in all the points and even the light of overload is lighted.

It is something of the 611E mother card, but I am not familiarized with issues on the mother card. Could someone give me a hand? What can I check in the mother card? Where does it go the signal to the VCA fader from? Pin 36, 48 and 6?...

I will check mute/solo switch wireing, just in case, but everything lights well and looks fine.

Thanks in advance.

Best regards.

Oihan

[Chris Simon]

First thing to check is: does the VU meter respond to VCA to Meters mode, by moving as you move the fader? If not, check the 5 volt, 0 volt, and fader wiper voltages. These are on pins 35, 33, and 25 respectively on the 82E13 card, and 74, 77, and 75 on the Lower Bus section of the motherboard. If you see good voltages on the '13 card but not on the moterboard, suspect the '13 card edge connector soldering to the motherboard. Also, don't discount the VCA ribbon from the console to the computer rack.