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-   -   Help needed on Soundcraft 2400 meter bridge (https://www.gearslutz.com/board/geekslutz-forum/35527-help-needed-soundcraft-2400-meter-bridge.html)

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?

ruudman

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.

Tony

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.

Thanks

Bill