Soundtech 6300 PA repair (schematic needed)

[antsap]

Hi everyone. I'm new to this forum. I'm working on trying to repair a soundTech 6300 combo PA for a family friend.

I'm in desperate need of the schematic and I can't seem to locate one or a source online. Anyone holding or have any suggestions?

The PA was blowing fuses instantly. I took it apart and confirmed that the power supply and wiring was ok. I removed all transistors, rectifiers, and and voltage regulators and confirmed that they were ok.
This left the power transistors/amp ... which was bad. I found a replacement for that on ebay and swapped it out.

The unit now powers up fine and doesn't overdraw or blow fuses ... but I'm not getting any sound.
It pops the speakers and has a quiet buzz when powered up, so something is going on.

Time to dig in deeper and start troubleshooting where I'm getting signals and where I'm not etc.

Any ideas on getting my hands on a schematic?

Thanks for the help!

[Leo_Gnardo]

Sorry no schematic, I'm sure someone will post one or a link for you. Also I'm not 100% familiar with your particular model, but many of this type mix/amp have preamp out or mix bus out and power amp in jacks, ordinarily normalled - that is internally arranged so that if no other selection is made with patch cables your main PA mix goes thru graphic EQ's then on to power amp inputs. Sometimes similar for monitor mixes. Those normalled jacks often develop corrosion over time and fail to pass signal. To test, you can apply the output of a signal generator (or keyboard instrument, Ipod output, whatever signal source you may have) to the power amp inputs to see whether they're working, then to graphic EQ inputs, see if those are working. Sometimes simply exercising the jacks brings back the normalling function, sometimes a shot of quality cleaner spray such as Caig DeOxit will help. If they're really corroded badly you may have to replace. Somewhere we have a sticky that covers this: "The dreaded effects loop jack problem," something like that.

[Jazz P Bass]

Sound Tech Schematics