EQ in and/or Split in cuts signal in the channel

[oyanliz]

Hi,

We have a channel strip where pushing Split or EQ in switch, cuts the signal and stops sounding the incoming signal on the channel. It seems is something wrong in the motherboard. We have replaced all the cards (amplifier, VCA, dynamic, EQ, Logic...) and also we have tryed with another EQ switch card (T82312).

Seems that split and EQ switch are working fine.

I have tryed to find info in the forum, but I did not find any similar issue.

I would apreciate any help.

Thanks i advance.

Regards.

[amillar]

This sounds to me like it could be a bad connection to the switch card? If I remember right that these are "fork" style connectors, it might be worth giving the connections on the 611 a VERY GENTLE squeeze with a pair of fine nosed pliers.

This was quite a common problem, even on new channels.

Good luck, Andy

[oyanliz]

I will check and I will write back.

Thank you so much Andy!

Best regards.

Oihan

[oyanliz]

Hi,

I left this issue "for repairing list" until today! I am trying to do another maintenance revision to the console and today have been fighting with this channel Strip.
SPLIT switch and EQ switch are ok. I revised all the wires and continuity between EQ switch, SPLIT switch, EQ card edge pins and Low Pass Filter pot. Everything seems fine (eq card swapped as well), so I suspect that the issue is on LMF or LF gain pot (when I rotate them, makes strange noise).
Tomorrow I will remove a pot from another strip and I will test again.
Does someone know if these pots broken very often? Maybe I am going in a wrong way?

Thanks in advance

Regards

Oihan

[oyanliz]

Yesterday I spend all the day doing more tests and have been squeezing the "fork" style connectors one more time, before start replacing the 22KOhm pots. I do not know what happened, but now the channel does not sound. Signal input is ok in the channel, but pre vca does not sound (just a very small signal). I thought it could be the SPLIT selector, so I replaced it, but not success.

So now the channel does not even sound via large fader.

Any help I will apreciate so much.

Thanks in advance.

Best regards.

Oihan

[oyanliz]

Hi,

I have been doing some tests. The SPLIT switch is ok and the pot switches of both filters too. Input, VCA, eq and dynamic cards are also working fine. Something in the motherboard, arround eq signal, is not ok, but I can not find the issue. I have attached the schematic with the  signal flow issue through the channel strip. When the EQ is not activated, the signal is attenuated on VCA fader (very very low signal) and when it is activated, the signal is cut. In the small fader, dynamic is working and split (filtering) also is working, but when EQ is activated (MON), the signal is cut. EQ switch card have been replaced also.

Can cause any issue a bad pot of the EQ, when EQ is not activated? Is there any critical thing I should check in the motherboard?

Any idea... will be welcome!!

Thanks in advance.

Oihan.

[oyanliz]

Hi all,

I never could fix the EQ issue of this strip. Now another issue came up on the same channel strip. The VCA fader it is not working. I have swapped the Amp card, VCA card and Group amp card... all off them working fine.

Now, when routing signal via small fader, the signal is ok before VCA (small fader up, LF and RF switches pushed, INPUT switch pushed and not pushed), the OUTPUT switch of the small fader is on, the signal is cut. Could be something in the logic card? Or multiplexer card?

Is there any relation with the EQ issue? The EQ card and all switch cards and switches are ok... but when EQ is activated, the signal is cut always.

I have updated the issues signal flow diagram.

Any help it will be appreciated.

Thanks in advance.

Best regards.

Oihan