There are NO "yellow" overload LED's period. The clip or overload RED LED's are just above the PFL buttons for selecting a solo channel. There are "yellow" signal received lights (level set) up near the trim controls. In normal operation these will light when signal is received. Here is schematic for the PMP5000 which is really identical for the 6000.
http://elektrotanya.com/behringer_europower-p0569_hca2400_sps1000_dpx_pmp-1280s_5000_sch.pdf/download.html This has part of the DSP and PS and the PA circuits.
Scroll down to "get manual" and click on it to download. Ignore other download links on the page.
Try turning off the Phantom power if it might be on... If that stops the hum, something is the matter with the bypasses feeding Phantom power to those channels... Possible problem might be shorting of one of the coupling caps at the preamp input. The PMH5000 drawings are more accurate at the input circuits. You will note that the level set LED's are the yellows, and the clip/PFL LED's are the red ones. I suspect that RF bypass caps such as C110 or C121 (example typical for channel one) might be shorted. This makes noise on the Phantom power line unbalanced and will get into the channel where one of these caps is shorted. Do a test: Plug a shorting jack that shorts the tip to the sleeve intot he inssert for the channel. With the LOW CUT button up, observe is the level set LED for that channel dims or goes out. If it does, then I supect you have a shorted RF bypass cap at the input..The next test involves driving a KNOWN balanced signal into the XLR jack and using a TRS in tthe inout 1/4 inch, test the levels with an oscilloscope to verify the hot and the return have equal amplitudes. I they don't, congratualtions you have to tear the main board out... lots of knobs and screws to access the inout circuits and verifuy the cause... it could ALSO be a bad transistor in the inout pair, etc...
913 views
Usually answered in minutes!
×