I got a used MG-1 off of eBay last Christmas and have enjoyed learning how to synthesize sounds with it. However, it seems that Tones 1 and 2 are never in tune with each other or with Polyphony-- or even a tuner for that matter. If I only have Tone 1’s volume up, and I try playing an octave or two, by the time I reach the last note it’s way off. I don’t think this is normal… The same thing happens with Tone 2. It’s really annoying when I want to play with the Polyphony and have the other Tones turned up to accent the Polyphony and they aren’t in tune. I can adjust the tuning knobs to get it in tune on maybe one key, but it’s never consistent. (For example, if it’s in tune somewhere it’s out of tune everywhere else on the keyboard)
Anyone know what the problem might be and how I can fix it?
Yes, it’s a voltage scaling problem. This is easily adjusted with a tweaker.
Service notes available here:
http://www.synthmania.com/Realistic%20MG-1%20Concertmate/Images/Realistic%20MG-1%20Service%20Manual.rar
Pages 16-18 describe the procedure.
I’m not familiar with the inner workings of the MG-1 at all…
Judging by the manual, I’ll have a shot at fixing it without having to open it up? I just don’t have any experience with electronics.
All you need is a decent tuner and a tweaker (small screwdriver), no need to open it up: all the adjustments are accessible from the rear panel (read the document). You just set the MG controls as stated, play a note and adjust the appropriate rear pot until it’s in tune, then repeat with higher octaves which gives you your scale back. Hopefully you don’t need to do the internal adjustment mentioned on page 16: start from page 17.
Yeah I just had no idea what I was reading… and I had no clue what you meant by “tweaker”, lol. Okay I’ll give that a shot!
Just looked up tweaker on Google and there are some dodgy defintions 
. Not sure if it’s a British term or just a Brisish television term (I work in broadcast television where we have all sorts of silly words like cans=headphones).
This is what I mean (a trimmer apparently) as the plastic stops you coming into any contact with metal, unlike a screwdriver:
Well I got them in tune but I’m having a really weird problem with the Tone Sources. When I press a key and then press another key, it’s as if the Keyboard Glide is up all the way (Slow), even though it’s on Fast. 
EDIT: Nope, I can’t keep them in tune. I have hard time zero beating the Tone Sources High/Low A with Polyphony consistently. I’m reading the troubleshooting section and Problems 15-17 seem to all apply. Any input on what I should do to fix this?
I hate to be annoying but it’s been a few months and I haven’t been able to use my synth, and I’d like to know if anybody could help me fix this problem or point me in the right direction. I’d hate to sell my MG-1 but it’s not worth it to not be able to use the tones to their full potential, so if I must then I will sell it.
In my opinion, your choices are:
- Sell it as-is, clearly stating that it has problems.
- Sell it as you may have bought it: described as working. This will pass the problems to someone else.
- Donate it to someone.
- Find someone who can repair it for you.
- Sell it off piece by piece. You may help several people and make more money, but it’s more work for you.
It basically comes down to your finances, patience and honesty.
To some people, money is worth more than honesty. To others, no.
Same for everything else. It’s all subjective and up to you.
MG-1 is pretty easy to work on if you know your way around. They are small, light, therefore relatively easy to ship. You should consider sending it off for service if there are no qualified technicians in your area. My friend and customer, Dave, is a component level trouble shooting technician who really likes his MG-1. Dave says that these are increasing in popularity and value, and there is a Yahoo group specifically for the MG-1. We collaborated a little on the electronic aspect of his restoration project, but mostly I got involved doing some case work. He wanted something classier than the molded plastic end panels, and due the their structural nature, you can’t just screw on a piece of wood. I built a pair of router jigs to route out the channels that makes this work.
We chose some black walnut with the sapwood showing along the top edge for these parts. Now that the jigs are available, it is pretty easy to make these out of any wood of choice. The only complication is the extra piece on either side that covers the area next to the ends of the keyboard. Dave is not happy with the way this looks, and is going to come over and collaborate a little more on the exact fit and aesthetics.
@livingtoast
I got to this board a little late it looks like, but mine has had that glide problem and it’s not much of an issue. It just seems to sometimes incorrectly read the furthest down position as the longest glide. Usually you can slide it up briefly and back down and it will correct itself. Or just don’t keep it all the way down, move it very slightly up.
Thanks for the tuning info, cause I’m dealing with that same issue, about to try the fix provided in the docs. awesome, thanks.