I have a pretty old JBL ESC 200 Surround System.
So i would like to attempt to repair this. I have a small amount of knowledge and i'm fairly handy with a soldering iron, but i have no idea where to start to isolate the problem.
I'm looking for any advice or tips and i can certainly post images of the internals of the system.
a) Hunt down a schematic for this system. JBL is still in business, and may be helpful. HiFi Engine may be another source, or a plain internet search.
b) What you can do without the schematic: Look for any blown fuses. Quite often these devices have internal fuses that are not accessible from the back. They are usually board mounted and quite visible when the guts are removed. The fuses may also be in a small black holder - so look for that as well. The schematic will also indicate fusible links - which do not look like fuses. Look for any mechanical problems - broken wires, loose connectors and such. Quite common as it happens, especially in stuff made in the early days of RoHS compliance.
c) Marginally possible without schematic: As the sub-woofer is driven from a single amplifier module, it is quite possible that this is blown. These modules are pretty basic and shared in common and shared amongst many devices. The schematic will tell you voltages and give you the pin-out, but if you can establish that it is bad, you may be able to replace it from the part number stamped on it. It will be a fairly large chip connected to a heat-sink.
This is not rocket science, but it does require intelligent diagnostics to prevent wasting time doing shotgun substitutions.
Owner's Manual here:https://www.manualslib.com/manual/79188 ... sc200.html
Service Manual (possibly) here: http://www.eserviceinfo.com/downloadsm/ ... SC200.html