How to fix/replace a tuning pot?

[davidb]

Hello,

I believe that the tuning pot on my Roland RD300 needs to be replaced. When I hit a note, the note will hit the right pitch, but then after a second or so the pitch will fluctuate up to 6Hz, going up and down. Can anyone tell me if this is is something that I can do on my own? I have no experience fixing digital pianos. If so, can you give me instructions including where I can buy parts (if needed)? Any help is greatly greatly appreciated. Thanks!

-David

[Prague]

It doesn't sound like a tuning pot problem, but perhaps you've already checked all of the possibilities.

 

Get the original replacement part from rolandus.com

[JMcS]

Has it always done this or did it start recently?

 

Years ago I purchased a Roland piano type keyboard whose pitch would fluctuate if a key was pressed repeatedly. I brought it back to the dealer and he checked with Roland about it. He was told that it was a "design feature". The dealer exchanged that keyboard for another Roland instrument that still did it but had more features.

 

Good Luck

[Sven Golly]

I've said it before, I'll say it again... if you have to ask about repairing your gear on your own, you probably shouldn't attempt it.

 

Take it in to a Roland authorized service center, get a quote, and decide on your options then.

 

If you have to ask about cleaning/replacing a pot, then you're only asking for trouble once you've got the unit open. Sorry if that sounds harsh, but that's how I'm calling it.

[eric]

For some odd reason (perhaps the first weekend Jim Beam), I am reminded of a song I used to sing when I was a young hooligan in elementary school. I think it was called "There's a hole in the bucket" and the words were something like this. It was Liza and Henry exchanging verses. I was actually about 1/4 of my way into typing it from memory and it was taking a long time. I just did a Google search (Sven better give me props) and I found the song lyrics:

 

There's a hole in the bucket, dear Liza, dear Liza,

There's a hole in the bucket, dear Liza, a hole.

 

So fix it dear Henry, dear Henry, dear Henry,

So fix it dear Henry, dear Henry, fix it.

 

With what should I fix it, dear Liza, dear Liza,

With what should I fix it, dear Liza, with what?

 

With straw, dear Henry, dear Henry, dear Henry,

With straw, dear Henry, dear Henry, with straw.

 

But the straw is too long, dear Liza, dear Liza,

The straw is too long, dear Liza, too long.

 

So cut it dear Henry, dear Henry, dear Henry,

So cut it dear Henry, dear Henry, cut it!

 

With what should I cut it, dear Liza, dear Liza,

With what should I cut it, dear Liza, with what?

 

Use the hatchet, dear Henry, dear Henry, dear Henry,

Use the hatchet, dear Henry, the hatchet.

 

But the hatchet's too dull, dear Liza, dear Liza,

The hatchet's too dull, dear Liza, too dull.

 

So, sharpen it, dear Henry, dear Henry, dear Henry,

So sharpen it dear Henry, dear Henry, sharpen it!

 

With what should I sharpen it, dear Liza, dear Liza,

With what should I sharpen, dear Liza, with what?

 

Use the stone, dear Henry, dear Henry, dear Henry,

Use the stone, dear Henry, dear Henry, the stone.

 

But the stone is too dry, dear Liza, dear Liza,

The stone is too dry, dear Liza, too dry.

 

So wet it, dear Henry, dear Henry, dear Henry,

So wet it dear Henry, dear Henry, wet it.

 

With what should I wet it, dear Liza, dear Liza,

With what should I wet it, dear Liza, with what?

 

With water, dear Henry, dear Henry, dear Henry,

With water, dear Henry, dear Henry, water.

 

With what should I carry it, dear Liza, dear Liza,

With what should I carry it dear Liza, with what?

 

Use the bucket dear Henry, dear Henry, dear Henry,

Use the bucket, dear Henry, dear Henry, the bucket!

 

There's a hole in the bucket, dear Liza, dear Liza,

There's a hole in the bucket, dear Liza, a hole.

 

[Sven Golly]

Originally posted by eric:

I was actually about 1/4 of my way into typing it from memory and it was taking a long time. I just did a Google search (Sven better give me props) and I found the song lyrics:

You da man, young Eric, young Eric, young Eric

You da man, young Eric, young Eric, da man!

 

[Byrdman]

Can you hook it up to MIDI. See if any pitch bend info is coming out of the instrument.

 

Or its just possible pitch bend is being sent to the instrument - whats your MIDI setup look like?

[Sven Golly]

Originally posted by Byrdman:

Can you hook it up to MIDI. See if any pitch bend info is coming out of the instrument.

I thought about that, but the RD300 (note: not the RD300SX) doesn't have any pitch lever or wheel. I'd actually written a 3 paragraph explanation on how to check to see if it was a dirty/wonky pitch lever, then realized what board he's actually got.

[dementedchord]

the hardest part of replacing the pot is locating a replacement... assuming you've used an iron before and are smart enough to turn the board off first... unfortunately a lotta repair guy's tend to horde parts and not sell them... you could try replacing the pot with 2 resistors... you'll not be able to adjust it anymore obviously... the way that tunig pot works is it's presented with a voltageon one end and the other end is grounded the wiper then outputs a voltage proportional to it's position... so if you take 2 resistors somewhat arbitrary in value but precision matched... solder them end to end then one to the supply voltage the otherend to ground and the "wiper" connect to the middle it should work... this is assuming (safe assumption) that it's not being caused by a fluctuation in the voltage it's self.... good luck...

[keynote]

Sounds like it may be time for a new Keyboard eh?

 

PS: I think the pitch problem was a common occurence with the RD300. I've heard others complain about the same phenomenon. It might also cost more to take it in and try to have it fixed then you could actually sell it for. The average price for a used RD-300 is under $400. Not sure what your budget is but almost any Stage Piano on the market today would be a giant leap forward over the RD-300 in my opinion. For example the RD-300SX. But if you have the dough I would go with the 700SX. Better Piano sound and more features. Or try and fix what you have. The choice is yours of course. Not sure though that you will actually be able to fix that pitch problem. Like I said, I think it was inherent to that particular model.

[Byrdman]

Originally posted by Sven Golly:

Originally posted by Byrdman:

Can you hook it up to MIDI. See if any pitch bend info is coming out of the instrument.

I thought about that, but the RD300 (note: not the RD300SX) doesn't have any pitch lever or wheel. I'd actually written a 3 paragraph explanation on how to check to see if it was a dirty/wonky pitch lever, then realized what board he's actually got.

What about after touch or wheels - its possible to map either to pitch bend. Then there is those infrared thingees. The thing may have got itself into some weird configuration.

 

PS - I am amazed that a relatively new design like this would not have its tuning derived from a crystal. Sounds like this is not the case though,. judging by other responses.

[Sven Golly]

Originally posted by Byrdman:

What about after touch or wheels - its possible to map either to pitch bend. Then there is those infrared thingees. The thing may have got itself into some weird configuration.

 

PS - I am amazed that a relatively new design like this would not have its tuning derived from a crystal. Sounds like this is not the case though,. judging by other responses.

This is an RD300, c.1986, not an RD300SX, c.2006. No pitch bend capabilities whatsoever. No wheel, no lever, I don't think even AT.