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Vintage Synth Repair

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MC-505 groovebox

MC-505 groovebox

2013-02-25 by Andres

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.

Re: MC-505 groovebox

2013-02-25 by alesisfusion8hd

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:
Show quoted textHide quoted text
>
> 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.
>

Re: MC-505 groovebox

2013-02-28 by Andres

Thanks for your answer François, I will do that and let you know.

Andres

--- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@...> wrote:
Show quoted textHide quoted text
>
> 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.
> >
>

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