Vintage Synth Repair

Hi Andres,
never opened a Groovebox, and I don't even have the Service Manual. However, I assume the Groovebox is driven by a CPU. I'd check if grounding the RESET pin on this CPU starts the show. If so, your CPU and all its folks (memories, sub-cpus, ...) are OK; the issue is located in the start-up circuit.

I had to deal with this quite recently on a DX7 and a Kawai.

François


--- In vintagesynthrepair@yahoogroups.com, "Andres" <nanodocl@...> wrote:
>
> Hi I am new, thanks to allow me to join this group.
> 
> I am looking for some information to help me to repair my Roland MC-505 groovebox.
> I have a degree in electronics but this is more complicated than I thoght. The device turns on, no information on the display is showed. I check the power supply and voltages are correct. LCD its ok. 
> I got the service manual from a google search and one of the first steps is enter into test mode, but no luck.
> English it is not my first language, so my appoligies about my redaction mistakes. Any information is welcome.
> 
> thank you all.
>