Hi everyone! I've recently acquired a cheap (and broken : ) dn780 reverb. It has a super noisy audio output, it gets a little bit better using program 31 (delay line) but everything else is a mess. I followed the service manual instructions and I found the culprit in the DSP board. Everything else is ok. Now, I know that this board is almost impossible to rework/fix: the pcb traces are super tiny, the DSP chip is unobtainable (and soldered in the socket, kinda strange from my point of view) and last but not least it wasn't meant to be fixed by the average tech. That said I just wanted to know if someone more experienced here attempted to fix this board and knows how it works in detail. From the schematics I roughly understand how it works, but I'm no engineer so I don't grasp everything. One thing that I noticed is that the O/Load (Overload???) led is always on apart when using program 31. This is connected to a monostable multivibrator that seems to command the write cycles to the sram, if that makes sense. As of now my intention is to start replacing all the dram/sram chip with NOS ones, hoping the problems is a broken one. If anyone has suggestions or paper/manuals to read that will be useful they're welcome. I'm also looking for the datasheet of the original dsp: the ones in my unit is a weitek wtl1010jc.
Thanks,
Marco
Thanks,
Marco