pinebrookjohn Messages: 4 Registered: January 2010 Location: scranton
Junior Member
hello guy/girls. i am having a problem with my pa it first 5 channels dont work but the 6th one does what could be the problem? i clean all the pots and it didnt help at all? thanks in advance
kustomoholic Messages: 227 Registered: March 2009 Location: Tulsa,oklahoma
Senior Member
You might try working the molex connectors from the "bad" preamp boards...could be as simple as a poor connection and working the connectors might get you back in a good contact situation..I am not sure how the thing is wired internally but give it a shot...
Kraig
stevem Messages: 4728 Registered: June 2004 Location: NY
Senior Member
I would say that its time to bring it to a tech as my guess is that each channel is a seperate circuit module and they are all set up in parallel feeding the mixers driver stage.
This means that only three things are possible.
1) The moldex connector is not feeding power to these channels.
2) The moldex connector is not passing the input or output signal
3) All 5 channels have a dead IC chip and hence no gain,
pleat Messages: 1452 Registered: June 2004 Location: Belding, Mi
Senior Member
Since you don't know the history of the PA, I'd agree that 90% of the problems will lay in the molex connectors that jump from channel to channel. Not sure how much you want to dive into fixing it yourself but, if the last channel is working, the plug that feeding it seems to be working, you might want to remove the first channel out of the chassis and swap itto the working channel, if that works, then I'd guess your problem is in the connector plugs and a good cleaning of the actual plugs should bring all the channels back to life. My guess is, if you swap all the non working channels into the channel slot that is working and they don't work in the channel 6 spot, then I would guess someone at some time took a line from a speaker output and plugged it into the input of the non working channels, frying the pre amp.
Keep us posted
pleat
pinebrookjohn Messages: 4 Registered: January 2010 Location: scranton
Junior Member
pleat wrote on Sun, 31 January 2010 13:22
Since you don't know the history of the PA, I'd agree that 90% of the problems will lay in the molex connectors that jump from channel to channel. Not sure how much you want to dive into fixing it yourself but, if the last channel is working, the plug that feeding it seems to be working, you might want to remove the first channel out of the chassis and swap itto the working channel, if that works, then I'd guess your problem is in the connector plugs and a good cleaning of the actual plugs should bring all the channels back to life. My guess is, if you swap all the non working channels into the channel slot that is working and they don't work in the channel 6 spot, then I would guess someone at some time took a line from a speaker output and plugged it into the input of the non working channels, frying the pre amp.
Keep us posted
pleat
thanks everyone for your input. ill try messing with the molex connectors next and go from there. just one question if the pre amp was fried wouldnt all 6 channels not be working?
stevem Messages: 4728 Registered: June 2004 Location: NY
Senior Member
No, as each channel has within it multiple preamp/gain stages.
Only the driver/ output stage, effect/reverb stage and the power supply are common to all the channels