Zero 88 level 12

[IRW]

Hi All,

Before anyone says it, I tried phoning Zero88 today, but must have missed their office hours, and could do with solving this by tomorrow evening!

 

I have, in my collection of small analogue desks at work, a Level 12. Nothing clever- a two preset jobbie, with a timer knob above each preset master, and a preset flash button above each master.

 

Preset A does not want to work properly, and I was wondering if anyone on here could throw some ideas at me?

 

The following has been proven:

Preset B works completely as expected

Preset A fader is fine (by means of swapping it with B, and backed up with multimeter readings)

Preset A timer knob is fine (by means of swapping it with B)

Preset A flash button is fine, and when activated, any levels set on preset A will output correctly

 

All other components on the PCB inside the console look fine. Does anyone have a circuit diagram for the PCB inside a Level 12/18/24 to aid with troubleshooting?

 

Thanks,

Ian

[DrV]

Hi All,

Before anyone says it, I tried phoning Zero88 today, but must have missed their office hours, and could do with solving this by tomorrow evening!

 

I have, in my collection of small analogue desks at work, a Level 12. Nothing clever- a two preset jobbie, with a timer knob above each preset master, and a preset flash button above each master.

 

Preset A does not want to work properly, and I was wondering if anyone on here could throw some ideas at me?

 

The following has been proven:

Preset B works completely as expected

Preset A fader is fine (by means of swapping it with B, and backed up with multimeter readings)

Preset A timer knob is fine (by means of swapping it with B)

Preset A flash button is fine, and when activated, any levels set on preset A will output correctly

 

All other components on the PCB inside the console look fine. Does anyone have a circuit diagram for the PCB inside a Level 12/18/24 to aid with troubleshooting?

 

Thanks,

Ian

 

But you haven't said what it actually does wrong - what are the symptoms?

 

Dave

[IRW]

But you haven't said what it actually does wrong - what are the symptoms?

 

Dave

 

D'oh! Sorry!

 

Pushing the Preset A master fader up to 10 does not output anything, but the preset A flash button does work, as does the whole of preset B.

[timd]

I'd be looking for any IC's in chip holders around the preset A fader you could swap (assuming it's not SMD). Also an inspection of tracks under a magnifier.

 

Beyond that, you're probably looking at a failed discrete component, which would be a pain to find.

 

Tim

[dbuckley]

If the Lever12 is an all analogue desk, then the chances are that the masters are driving a PWM generator, as thats how analogue desks do the dipless crossfade. As Preset A works, you can compare Preset B readings (and scope traces) with preset A.

[ianknight]

Ian - try swapping IC2 - the IC that isn't the LM324. That seems to be sat between the Master fader and the circuit that does the ramp generation for the crossfading.

 

IC1 is probably ok because one quarter of that is driven directly by the flash button and you know that works. Also a lot of these older desks suffer at various times with dry joints, give the PCB a good going over with a lens and a pen torch...

[IRW]

Thanks all for your help!

 

I gave Zero88 a ring today, and they pointed me towards a circuit diagram, which I used to trace preset A's path. I still couldn't find anything particularly wrong, so ended up just reflowing various solder joints, and lo-and behold, it is now working absolutely fine!

 

Thanks,

 

Ian