Realistic EQ Problem- Pointers?

[Shominy]

Hi
I picked up a Realistic 31-2020 EQ. It works fine, except that the 30Hz slider on the right side does not work. What do I need to investigate to fix this?

Thanks,
Dean

 

[Lavane]

No sound at all?

 

[century tek]

When you say it does not work, does it slide up or down?

You're not really going to hear 30Hz but more like feel it.

 

[NH-MAN]

When you say it does not work, does it slide up or down?

You're not really going to hear 30Hz but more like feel it.

I would think since it works on the left he can tell its not working on the right

 

[century tek]

It might slide ok but not actually work. Or......physically broken slide switch!

Just seemed vague!

 

[Shominy]

I can hear the left side change, right slides and feels normal with no change in sound. What might I look for?

 

[regore]

If you've already given the 31 hertz slider a good spritz to no avail take the cover off, blow it out good and give it a good visual inspection. You might just luck out. Signs of discoloration or liquid spills should be easy to spot.
I own the Optimus 31-2025 which is a clone to yours and to be honest I've never even had the cover off.
Hi Fi engine has the owners manual for download but it won't be much help either.
Also check the operation of the IMX expander switch and see if restores the 31 hz. slider.
If all else fails, a service schematic may be needed. Almost un- obtainium !
Schematics are available online for some RS equipment. At least the thing still works.

 

[Lavane]

Are those sliders all separate? Or are they all soldered to a single PCB. I would look over the area around that slider. Look for cracks in the PCB, if the sliders are mounted on one, and cold or broken solder joints where the slider is soldered in. I've found components installed with a missing solder.
The componant leg luckily made enough contact to work. I bought an amp once that was originally a return that never made it back to the factory. The meter lights didn't work. The wire that feeds power to the meters was never soldered in place. It could be something that simple.

 

[Skywatcher]

Hi
I picked up a Realistic 31-2020 EQ. It works fine, except that the 30Hz slider on the right side does not work. What do I need to investigate to fix this?

Thanks,
Dean

A screwdriver to take the cover off to look. It could be a capacitor, or a bad solder joint, or even a bad/cracked slider internally. Or a funky OpAmp. Hard to say without seeing it...

 

[Shominy]

I will undress it tomorrow, if I can and see. I just wanted to know what to be looking for, and you guys have helped that. I will report back...

 

[Shominy]

I don't see anything obvious. Your better eagle eyes might see someting. The 30hz slider is left-most red one in all imgs.

Also- a Teac EQA-20 - not a Realistic.

 

[Shominy]

OK, found the problem. Contacts inside the slider have become detached. How much of a hassle/do-ability is it to do surgery.

Or do I need to look for a donor unit?

 

[Skywatcher]

OK, found the problem. Contacts inside the slider have become detached. How much of a hassle/do-ability is it to do surgery.

Or do I need to look for a donor unit?

View attachment 1948835

There is only one way to find out. Remove the slider and open it up. You'll need to read what value it is anyways to find a replacement if you can't put Humpty Dumpty back together.