I have a commercial mid 1980s solid state stereo preamp/mixer, which has a dual LED Bar Meter. (about 6 green on the bottom, two yellow above that, and a red on the top).
The preamp/mixer works well, but the LED meter is flakey. I have never worked with one of these, so before I tear into it, I want to know if these are all complete units, and are they fed off the actual preamp, or do they have a separate amp of their own?
What it's doing: One channel lights up every so often, and moves like it should. Then it goes off for awhile. The other channel does not light at all.
However, both channels do momentarily light up the red LED for a split second when I turn on the power to this preamp. So, that tells me that there is obviously power going to this LED meter, and that the meter LEDs do work.
I'll begin by looking for any loose connections, but what is the way to troubleshoot these if all connections are tight? If I measure voltages with my VOM, what sort of voltage would be normal?
(I have not been able to find a schematic for this device, so I'm on my own).