Realistic Wide-Range EQ problem?

imglocked

imglocked

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Hey everyone, hope yer summer is going well . . . todays patient is a Realistic EQ Model 31-2000, two channel, 10-band with level matching controls for each channel like those found on some Soundcraftsmen units (theoretically anyways) . . . recently, the right channel level indicators began to act wonky, ie: when the output level is matched to the input level, all three led's (the two red over/under and the green equal) are lit . . . the green remains steady, but the reds flicker extremely rapidly . . . the level control seems to function as it does increase/decrease the output when turned accordingly . . . the sound is not distorted at all, so I am guessing there is a problem in the led circuitry . . . I am searching for a service manual, but in the meanwhile if anyone has an idea, suggestion or comment, let 'er fly! . . .:yes:
 
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I have the same equalizer. I bought one new back in 1980. Sometimes, with different sound sources, I do notice it goes wonky, but as long as there is no distortion, then it's normal. The only time you have to adjust if the LED's show all red.

Here is what the Equalizer's owner's manual says:

Zero Gain Controls
The slide frequency controls will change the average level of the program material, (signal) as they are moved up or down from the "0" dB (flat) position. After having equalized your system, the average signal level to each channel of your Amplifier/Receiver would receive if you didn't use the Equalizer.

To restore the output level from the Equalizer to the original input level, the ZERO GAIN CONTROLS must be adjusted. There are three LED's above each control as indicators for setting the levels. These will ensure that you don't over-drive your Amplifier/Receiver or Speakers (which can result in distortion) and will make sure that the signal level of left and right channels are same.

After equalization, the LED indicators will light red. Adjust the ZERO GAIN CONTROL towards + or - so the center LED glows green. At this position, the average signal level of equalized signal will be the same as the original level.

NOTE: When adjusting ZERO GAIN CONTROLS you will find that the Red and green LED's flicker with variation in the program signal. Ideal settings of the ZERO GAIN CONTROLS will be when the only green LED's flicker (or midway between the points when the upper and lower red LED's flicker). Only when the red LED's stay on all the time it is necessary to adjust the ZERO GAIN CONTROLS.

Hope this helps.
 
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Thanks . . . that does shed some light . . . I see how the source makes the led's dance and I do see the left channel fluctuate re: what leds are lit and how, but regardless of music type, I am not able to get the right channel green led on by itself as I can w/ the left . . . I have reversed channels, used mono sources and even steady test tones, but always the same - when the green is lit steady, both red leds are flickering like candles in the wind . . . anyway, if and when you have a moment, and if the manual is not too big, might I get a copy of that manual as I am not the original owner and I do like to have at least the user manual for the equipment I acquire . . . thanks again.

Jim
 
Rather than post the obligatory "This Post Is Worthless Without Pics" banner, here's a pic of the one I got at GW last week. I was going to check it out this afternoon, but I took a nap instead. :D
 
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I have one of these aguys as well! it's currently in my needs some cleaning pile, but that will change this fall i think. ;) Nice little eq so far as i've used it.
 
Hi Imglocked
did you ever fix the fault with the right channel level leds ?
I have also just bought the same model and it has exactly the same fault as yours , works fine accept the leds are wonky on the left channel .
 
If you can find an owners manual, it should also have the schematic. Without schematic it is matter of using the the left/right symetry and see what components are out of value- if any. There should be a coarse adjustment inside the unit with the external adjustments being the fine adjustment. Apply the same signal ( a fixed tone) to both inputs and make sure all settings are the same, and then balance the LEDs accordingly.
 
I had one in 1980 as well. The red lights would flicker some. It was normal. I don't use EQ's anymore, but I did like the balancing feature. Its the main reason I bought that model.
 
Hi Lavane
the problem is not that the red lights will flicker some times it is that all three leds are on at the same time with some degree of brightness
where as the left channel only displays one led at a time ie level to low the left red led lights only. level to high the right red led lights only and when the level is correct the green centre led will light .
the behaviour of the right channel leds is completely different to the right channel leds with the same source .
 
I just bought one off the bay and it came with a schematic. :thmbsp:

If anyone has trouble accessing the attachment, PM me and I will email you a copy.

When time permits, I'll scan the entire document and make it available as well.

:smoke:
 

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Hi Reverb
Thanks for the schematic and taking the time to making it available online.
Hopefully now I will be able to fix it .
I would really be interested to see the rest of the documentation that you have to go with this eq .
 
I'll try and get you a copy of it. I went toe-to-toe with the Xerox machine yesterday trying to scan it as a multi-page PDF file. The Xerox won! :boxing:

I'll see if one of the folks who use it a lot can give me some guidance.
 
zero1lover said:
Thanks Reverb

Have you tried out your eq yet ? Has it got the same fault as mine by any chance ?
Click to expand...

Mine seems OK. The seller stated that one channel was "out" but after a little Dexoit, it is actually fine. The lights do bounce around a bit but usually it is to one side of green - not both.
 
Hi Reverb good to here your graphic is now working fine.
i have been watching the leds on mine and have seen that the right green led never goes out it may go dim but never goes compleatly out both the red leds seem to behave correctly
 
good news managed to fix my led problem was an easy fix once I had the schematic that Reverb provided . It was the 33uf capacitors in the drive circuit for the leds they act as filter and smoothing from the diodes on the output of the op amps . once I had replaced all 4 the leds behaved .
So a big thanks to Reverb for providing us all with the schematic .
 
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zero1lover said:
good news managed to fix my led problem was an easy fix once I had the schematic that Reverb provided . It was the 33uf capacitors in the drive circuit for the leds they act as filter and smoothing from the diodes on the output of the op amps . once I had replaced all 4 the leds behaved .
So a big thanks to Reverb for providing us all with the schematic .
Click to expand...


Glad to hear you got it going :) I have one in my loft system, and do really like it alot.
 
Zeners near rectifiers

I am trying to get some information on the 2 Zeners near the rectifiers in the power supply area for a 31-2009. If you have schematic for 31-2000a, could you possibly check the specks for me? My hope is they are similar.
 
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