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creativeblue 17th June 2005 11:54 AM

Help needed on Soundcraft 2400 meter bridge
Hi, the meter bridge of my soundcraft 2400 doesnt work in the right way, since a few days. They all flash in a strange way, like starting from the middle, and going down. These four "8-LED-bars" of each meter look like if they get too less current or something, cause only one of the four led-bars of each meter flashes in normal strength, and wich one of the four depends on the signal, where it has its maximum. Is the level up to -3 dB, only the third bar (from botton) shines bright, the others are much more darker.
This is on ALL meters, also the L/R meters. It makes no difference if I'm in spectrum-, groups- or slate-mode.
Then sometimes the meters switch completly of, or only glow very
low. But if they work, there is only ONE led-bar which shines bright, all others glow lower.
What could be the reason of this?
Is it possible that these Brown ICs I used in some of the channels are responsible for that, cause if they use more current, than the meters dont get enough? But the power supply is stable. Actually I changed the ones from the master back to original, and the problem is still there.
Actually the meters worked very well, after I changed these op amps,
a few weeks ago.
The problem causes, since I had a huge rock production on
the desk, with lots of high levels and some overload on the meters.
But this shouldnt be a problem for meters, to display overload?!
Please give some ideas. I also have changed the 4040 and 4069, which didnt make a difference. I dont know what to do now. hidz

Ruudman 17th June 2005 12:07 PM

Did it work proprely before you changed to Brown's?
What is their current draw compared to the TL's?
I've got a 2400 myself, please let us know the progress.

BTW, you checked that the MB's ribbon cable ain't squeezed?
The master VU's, do they light up?


creativeblue 17th June 2005 12:37 PM

Yes it worked befor I changed the ICs, and afterwards also!
I dont think it depends on the ICs i have changed, cause
they work well and didnt make any problems at all!

Current draw of what? Master = ED 2090, Meter control ED 2092,
Analyzer pcb ED 2096, if this is what you mean.

Does it make sense, to change the IC 1-3 ( 4069) on Board "Meter Control P.C.B. SC 1214 ISS.1" ?
I think they are CMOS and static sensitive, is it dangerous to touch them?
I allerady got some spares of 4069.

The ribbon cable is not squeesed.
The VUs work fine, I repaired them few weeks ago.

creativeblue 17th June 2005 12:50 PM

A I guess I understand you wrong.
I have changed the IC 1 and 2 in the master, got here OPA 2134 now, its like the same, but I feel a bit more punch in the bass area.
Also when using the RC4060, (new one) which I have now in some of the channels. I got the impression that it sounds more clear in the bottom area.
I also tried the OPA4227 and OPA4228 instead of the TL074, in the Master,
(IC 6 and 3) but changed them again. They also worked well, but I didnt really compare yet. I remind having sort of limiting effect when driving the master, which was more like bad distortion whith the TL074s.
I also tried OPA 2627 which also works fine, in the master.

tmarra 17th June 2005 04:02 PM

If all the meters are doing the same thing then it must be something to do with the power supply voltages. If I recall (and this is going way back in my memory bank) Soundcraft uses +/- 7.5VDC to run the logic IC's and +24VDC to actually power the LED's. The IC's you swaped out are powered from the Audio Supply (+/- 18VDC) and should have nothing to do with the problem your having.

I'd check to see if your getting the +/-7.5VDC at the meter bridge IC's before changing any IC's. I think you may find you lost one of those voltages.


creativeblue 21st June 2005 08:47 PM

Thank you everybody for your help, esp. tmarra thank you thumbsup , i solved the problem, all meters work fine now. jkthtyrt It was just a screw in a component in the power supply. tutt The LED was just a bit lower, cause there were only 7 volts instead of 24, so I didnt recognize that something could be wrong with the power supply.

Feel free to email me for any purpose.
Thanks!! boing

wbeith 10th January 2007 12:58 AM

Soundcraft 2400 Meterbridge
I found this thread searching for a solution to my LED meterbridge problem. My meters were working and now light in groups of 9 and when the tenth one lights the prior nine get very dim. I also do not have lights in the master VU's.

Can you describe where you located the rails? I found a rail with screws inside the console and all were tight. In the power supply all the wires appear to have spade lugs and are pushed into a connector on the left and right side of the power supply pc board.