Vintage Synth Repair

Hi everyone.

I recently picked up a Casio MIDI guitar controller. A really good example of old MIDI guitars. I think it uses the Roland setup on an Ibanez body. Anyway, the previous owner had it from new. The batteries died on stage years ago and he says he plugged in an ac adapter from his pedal board and that was the last time it worked. It was left in a cupboard unused and unloved for many years. I'm thinking wrong voltage or wrong polarity when he plugged in the a/c adapter..

I've not been able to find the circuit diagram although I have done a close visual inspection of the board and can see no signs of anything being burnt out.

Is anyone in the group familiar with this guitar?

It works perfectly as a passive guitar of course, not much to go wrong there.

Any help much appreciated.

Best regards

Tee.

Google is your friend, too :-)


http://elektrotanya.com/casio_mg-500_mg-510_sm_and_parts_list.pdf/download.html


Check Power Circuit components.


Daniel Forro




On 2 Oct, 2014, at 8:05 AM, xp_sucks@... [vintagesynthrepair]  
wrote:

>
>
>  Hi everyone.
>
>
> I recently picked up a Casio MIDI guitar controller. A really good  
> example of old MIDI guitars. I think it uses the Roland setup on an  
> Ibanez body. Anyway, the previous owner had it from new. The  
> batteries died on stage years ago and he says he plugged in an ac  
> adapter from his pedal board and that was the last time it worked.  
> It was left in a cupboard unused and unloved for many years. I'm  
> thinking wrong voltage or wrong polarity when he plugged in the a/c  
> adapter..
>
>
> I've not been able to find the circuit diagram although I have done  
> a close visual inspection of the board and can see no signs of  
> anything being burnt out.
>
>
> Is anyone in the group familiar with this guitar?
>
>
> It works perfectly as a passive guitar of course, not much to go  
> wrong there.
>
>
>
> Any help much appreciated.
>
>
>
> Best regards
>
>
> Tee.
>

Hi Tee,

Since the previous owner used an ac-adapter from a pedal board, we must assume that the correct voltage of 9 V DC was used. The unit should be diode protected internally against reverse polarity, but NOT against overvoltage!

Now, the Casio MG-510 is from the late 80s, so it probably needs some recapping ( new electrolytic capacitors ). Not so hard to do, but If you're not familiar with soldering etc. I suggest you to visit Grant Muller's site here. There's a very thorough documentation on how to recap an MG-510:

Casio MG-510 Midi Guitar | Grant Muller

Next you could study the service manual in detail. I've just uploaded it to this group. Have fun and good luck.

Bo