Upper Bus Card problem

[tlmaen]

Hi,
CH 18 never worked properly since I bought the Console.
It always had trouble with the Mic level in REC Mode.
The Problem was sometimes there, sometimes not, and I suspected Sub-Cards in the Channel.
Now I narrowed it down to the upper Bus card (at least that's what I think atm...).

- The Level is about 18db lower than any other Channel, if you apply the same signal to the Micpreamp input (It stays low throughout the channel. Ins snd, Cues, Grp out).
- If you swap in another working Channel, the problem stays with Slot 18, not with the Channel Module.
- The upper Bus Card connector looks like it was replaced in the past. I checked all the solder joints on the backside, they look good.
- The Connector has pins 24, 54 fitted, wich shouldn't make any difference as these pins are not present at the 611E Edge connector (E-Series).
- I double checked all of the BICC Connectors if they are in the right place (if they were in the wrong place, it would affect two channels at the same time).

Now Idea why the problem is...
Hope someone can help!

Thanks,
Tilmann

[Dave Dicson]

Maybe check the patchbay mic input and normally jacks and it's wiring to and from patchbay for channel 18?

[Richealey]

Try swapping the BICC connector with another pair. Put 17/18 in 19/20 or 19/20 in 17/18 and see if the fault follows 18s wiring to the patchbay. I agree with Dave, it could be patchbay normalling. If you patch a signal using a TT into the lower Mic In patch point you should
bypass the normal connections. You could have something shorting the patch connector in the patchrow like a nut that fell off during shipping. Another test would be to pull the BICC connector for 17/18, use a patch cord in Mic In 18 and with an ohm meter measure between the hot, cold, and shield at the end of the patch cord. There should be no connection between them. Then check the patch point above the Mic In. This would check the normals. If you find a short you'll know what you're looking for. Hope this helps.

[Dave Dicson]

I should have said this in my above post. Swap the BICC connectors with channel 17 or 19 on the bus card from the patchbay. If problem goes away, there is your answer patchbay and wiring. If the problem is still there on channel 18, check the little gold contacts in the blue edge connector that haven't shorted or are not making contact with channel strip mother board. I have seen this in the past. Good luck.