Roland GP 100 knobs?

Paul O'Bryan · Post by **Paul O'Bryan** » 20 Aug 2012 6:14 pm

Does anyone know where I could get hold of New Roland
Knobs to suite a Roland GP 100? Mine have that jittery problem

Jerry Overstreet · Post by **Jerry Overstreet** » 20 Aug 2012 7:31 pm

Is it just the knobs you need? Or are you having problems with the electronics?

I have a pair of knobs off a Boss unit that fit your shafts, but they're a bit taller and thicker. If you can use them, You're welcome to them for the delivery fees.

[Edit:] Oh wow, I just noticed you are in Australia. Don't know what's involved with shipping, but the offer stands.

Paul O'Bryan · Post by **Paul O'Bryan** » 20 Aug 2012 8:03 pm

Hey Jerry, when I turn the Parameter knob I think it is, the display jumps ahead two or three times more than it should and the same turning it backwards so I guess it's the actual mechanism that has the clicking feel when you turn it?

Jerry Overstreet · Post by **Jerry Overstreet** » 20 Aug 2012 8:23 pm

Yeah Paul, mine does the same thing. I just live with it. It must be a problem with the encoder circuit. I expect it needs to go to a proper Roland repair facility for a fix, if support is still available for these. Cheers, JO.

Len Amaral · Post by **Len Amaral** » 21 Aug 2012 6:07 am

Hi Paul:

It's not the knob but a characteristic of the unit. Try spinning the knobs back and forth real fast and see if that helps and then turn the knob slow to zero in on a parameter.

Regards,

Lenny

Paul O'Bryan · Post by **Paul O'Bryan** » 21 Aug 2012 6:38 pm

Hey Lenny, I have tracked down a new knob and mechanism from Roland Australia.
Do you think replacing it will fix the problem?

Len Amaral · Post by **Len Amaral** » 22 Aug 2012 7:29 am

I have 5 GP-100 units and they basically respond the same way. You can try changing the control to see what happens but it may not be an easy replacement.

Len Amaral · Post by **Len Amaral** » 22 Aug 2012 7:30 am

I have 5 GP-100 units and they basically respond the same way. You can try changing the control to see what happens but it may not be an easy replacement.

David Higginbotham · Post by **David Higginbotham** » 22 Aug 2012 4:46 pm

You may want to google the problem as I seem to remember the gear on the pot is the trouble rather than the actual knob. But it seems there was a remedy mentioned that was a fairly easy fix. These are one of the best units ever made!!!!!
Dave

emil noothout · Post by **emil noothout** » 22 Aug 2012 10:56 pm

I had the same problem, and cleaned the pots as described in this link:
http://www.jeffryhouser.com/index.cfm/2 ... ter-Repair
(if the link is not working: i googled Roland gp100 data wheel)
Now they work fine again.

George Webb · Post by **George Webb** » 27 Aug 2012 10:35 am

The GP 100 encoder can be easily replaced if you're comfortable opening the unit and soldering components.
I ordered two of this part from Mouser Electronics.
PN 688 -EC11B15242AF.

http://ca.mouser.com/ProductDetail/ALPS ... /qaFcTitOE

The shaft is a bit longer and the push button stroke is a bit longer. I think the shorter stroke is available as a different PN.

These two mount to a circuit board that is adjustable in height so the shaft (or knob position) can be set lower/higher. I recommend replacing both of them to achieve the same knob heights.

If you're only replacing one and want the same knob height you can cut the shaft shorter. (remember - put the shaft in the vice when you cut .. not the encoder !)

I found the longer push button stroke an improvement as I was sometimes pushing the button when I only intended to rotate it.

After a couple of years the new ones are still working perfectly.

George Webb

Jerry Overstreet · Post by **Jerry Overstreet** » 7 Nov 2018 8:25 am

I just wanted to Thank everybody for posting all this information for the GP100 jitters fix several years ago.

I finally got around to ordering these encoders from Mouser as suggested by George. They still have them in stock and they cost about $20 for 2 of them delivered.

I changed both the Numbers and Parameters encoders...or actually I had a friend do it for me as he has better irons etc. and my eyesight is not what it used to be.

There are 7 pins so desoldering and installing new ones takes a steady hand and swift iron work.

Anyway, I don't know whether anybody uses these anymore as they're well over 20 yrs. old, but if so, the parts are still available and the fix is golden.

Thanks again to everybody who participated in this thread.

George Webb · Post by **George Webb** » 7 Nov 2018 8:59 am

Jerry,

Glad to hear it!

George

Jerry Overstreet · Post by **Jerry Overstreet** » 7 Nov 2018 9:14 am

George Webb wrote:Jerry,

Glad to hear it!

George

Thanks for that Mouser info back when George. I've been using this unit mostly at home, but I'm glad now I can take it out and not be embarrassed thinking I have a Ventures Lead patch and it's jumped over to Van Halen Big Bottom or some such.

The detents seem a bit softer and I still jump past a patch on occasion, but that might just be Operator error.
The jitters problem randomly skipping many patches or incrementing up when you want to down etc. is solved. That's the important thing.

Len Amaral · Post by **Len Amaral** » 7 Nov 2018 1:21 pm

Gotta hand it to Roland for making a product that went out of production in 1995 and I'm still using my GP-100 after many years. Even though the unit has 200 presets and 200 user programs, I use a few reverbs and delays. A friend of mine who is a tech nerd set up a duel preset so reverb comes out of one speaker and delay out of the other. Nifty!

Jerry Overstreet · Post by **Jerry Overstreet** » 7 Nov 2018 3:55 pm

I have a bunch of Roland/Boss gear. They do what I want from electronics. My only issue is that support for older gear is not always available, but I suppose that's true for most electronic gear companies.

Len, I use my GP100 as the front end of one of my stereo rigs into a Mosvalve 500. I use the Clean Twin Pre for my clean steel settings and Fender type guitar tones...I have about a dozen presets for steel and a half dozen for guitar, lap steel and slides.

It gives me everything I want for all instruments. Sounds big and full for pedal steel. Has a tremendous amount of programming power as well as a ton of connections options.

Like all multi-fx units, one has to know what effects do, how they work, what the parameters mean and what you want them to do for you. You also have to be willing to spend much time setting up and tweaking them.

As a long time user of multi-fx/preamp units, I love having different settings for different situations...not one generic sound for everything all night long.

Yes, I still have a LeMay modded NV400 for some great mono tone and power, but I prefer my Multi-fx, stereo rigs for most occasions.

Call me a dinosaur, but all my stuff is mostly 90's era with a few 80's pieces here and there. Much is digital, but some analog too. It all sounds as good or better as any more recent gear I've listened to.

I like it so well, that I've backed up a lot of it with spare units as I know it won't last forever, case in point, the GP100 issue, but at least it can be repaired unlike much current gear.

Len Amaral · Post by **Len Amaral** » 7 Nov 2018 4:51 pm

Jerry, you are not a dinosaur but rather a player that appreciates good gear that works for you.

Btw, the GP-100 must have been a very popular processor in Japan as there are a number of them for sale on Ebay. Don’t forget to change the #2032 button battery in the unit as that retains your saved presets. Good to check it once in a while anyway to make sure the battery is not leaking.

Jerry Overstreet · Post by **Jerry Overstreet** » 7 Nov 2018 4:55 pm

Thanks for the battery tip Lenny. Yes, I changed it while I had the case open.

Jerry Overstreet · Post by **Jerry Overstreet** » 25 Aug 2025 2:09 pm

Another entry some 7 yrs. later.

Probably boring some of you to death, but I had another situation that is relevant to this one. I was hoping it might help some other users with units of these type encoders.

I had a Boss VF-1 half rack unit that had the Roland jitters. The problem was that it was erratic scrolling patches up and down. It might display patches higher or lower than the selection or not move from the current patch at all for several actions. Really just all over the place sometimes.

There are not replacement controls like this that I was able to find so I decided to try and fix it. I followed the Jeffrey Houser tute on repairing these encoders garnered from the previous threads and was able to get it working right again. https://www.jeffryhouser.com/index.cfm/ ... r#comments

These encoders all appear to work very much alike. This one I had was a 360 degree wheel with a detent switch.

I had some trepidation attempting this b'cuz my eyes are not what they used to be and the encoder unit has some teeny tiny tabs that must be bent back in order to separate the pot halves. Using an itty bitty jewelers pick and a pocket screwdriver I was able to open it up.

I did however have to disassemble the case of course, take pics of the assembly and figure out how the control's wiring ribbon attaches to the board connector so I could take it out of the unit to service it. It seems they are all different.

There's not much in there. Just the rotary wheel, the sensor and the 2 sets of electrical contacts. I did what the tute said and cleaned the little wheel and it's tee-tiny sensor with some alcohol and a Q-tip. Since this also has a push in switch, I very gently bent those 2 sets of contacts upwards so I thought they would make better contact when the knob was pushed in.

I was very happy when I found that this little exercise eliminated the jitters problem and the unit scrolls up or down through patches like it should.

I know some of you have units with these type of encoders and I thought maybe you adventurous souls that have units with this condition might find the information useful.

I would like to thank Jeffrey for posting this but I can't find a way to comment on his site. Happy pickin' guys and be careful driving if you're out over the upcoming Labor Day wknd.

Shaan Shirazi · Post by **Shaan Shirazi** » 26 Aug 2025 7:42 am

I too am a big fan on the GP-100 and am down to one nowadays. I have the FC-200 pedalboard that allows you to move up and down in banks of 10 and then select 1-9 so twisting the jittery knob is not a problem. I'm sure there is a smaller, more affordable midi controller that has the same functionality for those who aren't comfortable opening up their GP.

Jerry Overstreet · Post by **Jerry Overstreet** » 26 Aug 2025 4:28 pm

Sure Shaan, I realize this is not for everybody, but for those of us who have spent a lot of time programming patches and settings in these boxes and don't want to reconfigure their system with new and different gear, this seems like a worthwhile effort to me.

If anyone has this jitters issue and doesn't feel comfortable opening up the case and doing it, I expect any competent electronics tech could do it for a small fee.

I'm happy to do it as well with units that have the encoder boards that attach to the main board by ribbon connectors. Just can't do any soldering right now.

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