Channel 1-12 without signal

[energytom]

Hello dear d8b Fans!

Today my beloved d8b stopped working
I have the following problem:

Analog Channels 2-12 have no signal,
but the fader controlling and all other controls of this channels working fine.
Channel 1 works normal, but the signal sounds overload, even if it is not overloaded.
The sound is like signal peaking.
So channel one works but the signal is not OK.
Channel 2-12 not working. They did not show up any signal.
Everything else worked fine. Analog 13-24 works normal.

The following things I have tried out:
- Re-Install OS5.1
- Turn off for more than 10 Minutes
- Change MFX-Card Positions (2x MFX, 1 UFX are installed)
- Re-Connect Power Plugs and all cables
- Delete Startup and create new Startup-File.
- Deinstall 3 x ADAT Cards and re-install

Ever heard of this problem?
Maybe it is a cable problem inside the console, but I don't think, that the analog signal is split in 2 x 12 Channels.
Does anyone know something about the signal flow for the analog channels?

Thanks for your help.

Greetings
Tom

[Crash]

I would say a clock issue except it seems a bit localized for that. If i were in your shoes, I would give the ribbon reseat procedure a go. Search it for an explanation...

[energytom]

Hello!

No luck until now.
I have replugged the original Clock Card and open console to check the ribbon.
Everything seems to be good

Problem is still there

[csp]

Not sure what you mean by "to check the ribbon".

What you have to do is to remove (individually) every ribbon cable (and any other cable connected via a plug) then give them a good clean and carefully re-seat the cables, making sure that they are fully and well seated.

Also remove the clock card and give its terminals a very goog clean then re-seat it.

You can also try removing and re-setting all the external plugs and leads.

Generally undertaking all of these steps, seems to solve most of the desk's problems.

Let us know how you get on and welcome to the forum --- a first name is also nice.

Just one extra thing, even though there is no sound, do you have any signal showing on any/all of the VU meters for those channels?

The fact that the faders are working, indicates to me that there is either no or very low voltage getting to the microphone pre-amplifier section. A low voltage can cause the electronics to be internally biased incorrectly and this can either cause the circuit not to work or on occassions (depending upon the circuit design) to effectlvely struggle and result in gross distortion (which you say you have on Chnl1). This channel's electronics might be the first in the electronics chain and is sucking all of the little voltage that is present.

Checking, cleaning and re-seating the plugs, especially those going from the back of the section where the big plugs connects to the desk (and the connectors on the big plug itself), could quite possibly solve your problem.

If (and only if) you are experienced with a multi-meter, you could check the voltage going to the pre-amp board and then check the voltages at the power supply end of the big plug --- BUT ONLY DO THIS IF YOU HAVE SOME ELECTRONICS KNOWLEDGE.

David

[synthjoe]

Everything that David wrote plus...

...I don't think, that the analog signal is split in 2 x 12 Channels.

The console uses Cirrus Logic Crystal CS5360 stereo A/D chips for each pair of channels. So yes, the architecture inside is indeed 2x12 (or rather few more, including talkback, metering, etc.). It would be difficult to guess, but the ribbon cable procedure is a good place to start and maybe that even one of the power rail traces on the PCB are broken for some reason. If reseating the ribbon cables does not help, you'll probably have to find a tech to troubleshoot.