Roland Alpha Juno 2 Synthesizer Repairs

Roland Alpha Juno 2 Synthesizer

Roland Alpha Juno 2 Synthesizer

A couple of days ago I bought a used Roland Juno Alpha 2 off Ebay for a really great price. It had numerous problems, but I felt I could fix it and I’m happy to report that the Roland Juno 2 is in perfect working order now. Below are some notes about what was wrong with the Roland Juno 2 and the steps I took to correct the issues. At a glance, some of the issues were a broken joystick and bender/pitch wheel, a check battery message, a couple of dead keys, and an extremely dirty synth inside and out. I also was not sure if the output jacks, chorus, and membrane buttons were all working yet. This was a gamble purchase, but I felt the problems would hopefully be fixable.

First the Roland Juno 2 was in absolute filthy condition. I think this synth had the most dirt, grime, dust, and just about everything you can think of tucked away inside. It had never been opened and when I lifted the lid off the top of the synth I couldn’t believe it was still in operation. It took me about two hours to clean all the stuff out of it and check all the wiring to make sure everything was stable and connected properly. Once the Juno 2 was cleaned, I proceeded to change the battery.

Changing the battery proved to be much easier than expected with the exception that you have to lift out the key bed before you can slide out the CPU board with the battery connected to it. Be careful when doing this because the cpu is connected to a couple of slots under the key bed and you don’t want to yank it out and rip off an electronic component on the CPU board. Just be gentle and it will gradually slide out. The battery was soldered to the main board as expected, but unlike other synths I was actually able to solder a battery holder directly to the main board due to excellent pin hole spacing. I usually use wire leads but in this case my spare battery holders were an easy fit. I then popped a fresh battery in and later reset the Juno 2 in order to remove the “Check Battery” message.

Note you MUST reset the Roland Juno 2 after a battery replacement in order to clear out the error message “Check Battery”. This was a big problem I found a lot of people had around the web. Another important note is that I’ve seen quite a few Juno 2′s with leaky batteries. Be careful not to buy one with battery crap all over the CPU as that will likely give you a giant headache trying to repair the CPU board if that’s at all possible. I had a teeny tiny bit of leakage with my old battery and I felt extremely lucky I caught it in time. With the battery tucked under the Key bed, it will be IMPOSSIBLE to see by just opening the top cover. You may be able to poke a flash light on the side, but that’ll be tough. Be careful about leaky batteries!!

With the battery in operation, I then reloaded the factory “memory” presets into the Roland Juno 2 using my Mac iBook and Sysex Librarian. I found the Juno 2 factory sounds in sysex format in the Juno Yahoo Groups. They are easy to find there and everything loaded up just fine. Be sure to follow the instructions in the Juno Factory Kit because you must press the WRITE key at the same time as the DATA TRANSFER and BULK LOAD keys in order to transfer the factory patches from the computer to the Juno 2.

Fixing the Roland Juno 2 dead keys was pretty easy. You have to remove the key bed which is far easier than most keyboards. Then you have to turn it over and lift up the plastic strip locking the key in place. From there you can lift out the dead key pretty quickly. Under the silicon rubber piece you need to gently clean the carbon contacts with alcohol cleaner. I usually rub generously with a Q-tip until I see a light black color on the Q-tip. I stopped using the rubber eraser trick because it has failed every time with me. I have had almost 100% success with using a pure alcohol cleaner and rubbing gently with a Q-tip. Later when the keys were tested, all of the dead ones were brought back to life. The keys were fixed!!

Finally, I had to tackle the big problem of the broken joystick/pitch bend wheel. There were three things I had to do in order to fix this problem and it’s very important that you check each one.

1. Probably the most important, you need to twist the middle metal shaft with a screw driver so that the center line is “vertical” and not horizontal. In every case when the center shaft line set to horizontal, I got absolutely no pitch bend effect. Once I twisted it vertically, I got my pitch effect and modulation settings back.

2. You MUST make sure that the tiny allen screw at the bottom of the plastic pitch bend wheel is securely tightened. This is critical and leads to most problems found on a broken joystick. The allen screw is what secures the joystick to the center metal shaft. If this comes loose, the spring will become unstable and thus you’ll get an unstable joystick which likely will either not work or give you crazy results. I often read reports about goofy joysticks in the Roland Juno 2 and likely that’s because the allen screw is loose at the bottom. This a precision joystick and you MUST have everything tightly secured and in it’s proper place.

3. There are at least six contact points on the pitch bend wheel. You should clean those with contact cleaner to ensure proper flow of signals reach to and from the Roland Juno 2 CPU board. I dismantled the entire pitch bend wheel and cleaned everything which I’m sure helped in bringing the pitch bend wheel back to life.

One more note about the joystick. With mine, the top vertical stick part had broken off likely by someone who whacked the joystick against something when they weren’t looking. I can say that even with the vertical stick part broken off, the Joystick is 100% usable. Of course you can either replace the joystick plastic part with another spare from another keyboard or you can simply epoxy a stick on top if you like. The semi-circle portion of the joystick sticks out plenty to toggle the joystick with your finger or thumb. It might even be easier for you. The indentation where the stick broke off also offers a good way to grip the joystick and toggle it from side to side as well.

Modulation is easy by simply pressing the wheel forward. Unless you plan to resell a completely original Roland Juno 2, I wouldn’t hesitate at all buying a Roland Juno 2 with a broken Joystick. They are SUPER simple to fix and I now know that most problems are a result of one or several of points above not being addressed properly. Also note that the center metal shaft on the joystick is “ROUND” and not “SEMI ROUND” like on some other joysticks. I pulled one from a used Roland XP-10 for example and while it will work fine as a replacement, you will need to cut out a circular hole rather than use it’s SEMI Circle hole. Other than that, most any joystick could probably be put into the Roland JUno 2 with some slight modification.

After putting everything back together on the Roland Juno 2 I tested the chorus and membrane buttons and all worked. I now had a totally 100% working Roland Juno 2 Synthesizer. Hurray!!

The Roland Juno 2 is a pretty sweet synth. I also have the Roland MKS-50 and both are a joy to use. The Roland Alpha Juno 2 is probably the easiest synth I’ve ever repaired and if I ever found another broken one for cheap I would grab it instantly. A LOT of people have problems with this synth I found while researching the web and while it stumped me a bit with a few things, once I figured out the fix it was downhill from there. Do check out the Roland Juno 2 as it’s a very nice cheap analog synthesizer that sounds simply wonderful.

Here is a nice demo of the Roland Alpha 2 on YouTube by RetroSound.

About these ads

20 thoughts on “Roland Alpha Juno 2 Synthesizer Repairs

  1. Jim,
    Thank you for the detailed information for repairing Alpha Juno 2. Those vintage synths should deserve more respect! I didn’t know that Alpha Juno 2 had velocity AND after touch sensitive keyboard. How’s the feel of the keyboard, is it decent? I love fixing electronics as well (although I’m not that good at it), so I love posts like this.

    • Hello and thanks for the comment! Yes, the Roland Juno 2 has both velocity and after touch sensitivity. I’ve read that many believe that the feel of the keyboard is better on the Juno 2 than the Juno 1. Personally, I really like the feel of the Juno 2 keyboard. In fact they are semi-weighted as when you turn it over there are weights epoxied onto the bottom of the plastic keys. This alarmed me a tiny bit because I had recently finished a project with a Roland XP-80 that had bad epoxy. It melted and all of the metal weights fell off. So, for a brief moment I wondered if the Juno 2 would do the same, but I later found out that the XP-80 epoxy case was an isolated one with only a few select models if correct.

      The Roland Juno 2 is also smaller than most synths. My Juno-60 looks huge next to the Juno 2 and it’s even smaller than the JP-8000. Thus if you are looking for a synth with a small footprint, the Juno 2 is pretty cool. However, the Juno 2 is a bit heavy because of the metal bottom. The top part is plastic with membrane and plastic buttons. I really like how easy it is to adjust the mod depth/type, brilliance, and env time easily on the top of the synth. Plus the chord memory and portamento functions are fantastic. I grew up in the 80′s and early 90′s when early Techno and Rave was big with 2 Unlimited, LA Style, etc. and the Roland Juno 2 really reminds of this period of music.

      The Roland Juno 2 is about as RAW as it gets with synthesizers. It’s really gritty and untamed which really is different sounding to me. I really can’t believe people are selling these for so cheap. I highly recommend one if you see one for sell in your area. I don’t thin you’ll be disappointed. I have enjoyed my Roland MKS-50 which is the rack version, but the Roland Juno 2 is a different approach with the keys, alpha dial, and other functions at your fingertips. It’s great to have both!

      Thanks again! Have a great weekend! – Jim

  2. Hi Jim!

    Alpha Juno is perfect synth for electronic dance music. Italo disco, house, techno, acid, rave, d’n’b, trance, synth pop… everything goes. Very easy to program, GREAT sounding synth and still quite cheap. Who needs hundreds of knobs? :D My Alpha Juno had broken bender unit. Now it’s working like new. Thanks Jim!

  3. Just picked up a second Roland Juno 2 off Ebay for a great price. There were ten broken keys, but I suspect they just need some contact cleaning. Other than that, it’s likely to be another Juno 2 in perfect working order. Dual Juno 2 Synths!!

  4. Another important thing to do when you receive a broken or funny Roland Juno 2 is to do a factory reset. The second one I just purchased has some strange hanging noises and overall settings seemed tampered with. I initialized everything and now it’s operates 100%.

    Here’s the factory rest procedure for the Roland Juno 2:

    1) The Alpha Juno 2 must be powered off.
    2) The Memory Protect switch must be off.
    3) While holding down the PORTAMENTO and DATA TRANSFER buttons, turn on the power.
    4) Release the buttons.
    5) The display will show something like “Initlz Funct RAM”
    6) Turn the power off.
    7) Turn the power on.

    Note that the above procedure will replace any settings saved under TUNE/FUNCTION and MIDI with the factory original settings. In addition the “Check Battery” message will disappear after a successful battery replacement.

  5. Hi Everyone

    I have a special problem with the Roland Juno 2 that has 10 dead keys. There
    seems to be a pattern where two keys side by side are dead. Thus 5 sets of two
    adjacent keys spread across the keyboard. I also feel there likely is a
    pattern, but I haven’t had time to determine that yet.

    I was curious if anyone has had experience fixing dead keys that are not silicon
    rubber or carbon contact related. I feel this is a different issue as I have
    fixed many synth keys using the methods described with cleaning contacts. Note
    I did try cleaning the contacts and nothing fixed the problem.

    I will be completely dismantling the keybed and will look for either trace
    cracks or broken wires. Something is amiss for sure and I’m a bit stumped.

    Thanks for any ideas.

    Jim

  6. One thing I realized is that I already have another 100% working Roland Juno 2
    in my studio. I figured I would swap the keybeds and see what happens. If the
    keybed works 100% in the faulty Juno 2, then I would likely know that the
    previous keybed was indeed bad. If when I swap out the keybed it has the same
    key issues, then I’ll know it’s either a wiring, diode, or chip problem on the
    main board perhaps. That might also be a good way to test things. I’ll check
    that out and report back later.

  7. Here’s an update when swapping keybeds with a perfect working Juno 2 and the
    newly acquired faulty one.

    1. I put the keybed from the 2nd “faulty” Juno 2 into my 100% working Juno 2.
    The exact same keys were dead, thus I am now certain that the problem exists on
    the keybed and not on the main board. Now I know the keybed is the problem.

    2. The dead keys are as follows from the left most key. I believe the lower
    keybed starts at C1.

    Dead keys are ….

    E1, F1, C2, Db2, Ab2, A2
    E3, F3, C4, Db4

    All other keys work perfectly. Also note that the dead keys are 100% not
    working. Even if I play harder, nothing comes out.

    My next step probably will be to completely strip the faulty keybed and examine
    all of the rubber, contacts, wires, traces, and diodes.

    Time consuming perhaps, I don’t know, but at least I’m confident the keybed is
    the problem and not the main board.

    Another note is that when I midi in an external keyboard controller, all
    functions work perfectly on the faulty Juno 2 synth. It’s sounds fantastic,
    even the chorus. It’s 100% in working order with the exception of the 10 dead
    keys on the keybed.

    I feel I’m closer to the problem and I’ll update you on my progress shortly.

  8. I think I “may” have found the root of my problem. Here are two links to images
    I shot of the Roland Juno 2 keybed PCB board with the keys and rubber pieces
    removed.

    http://jimatwood.files.wordpress.com/2012/06/part1.jpg
    http://jimatwood.files.wordpress.com/2012/06/part2.jpg

    I used photoshop to indicate the dead key contact areas along with “yellow” and
    “red” lines that connect them. I found that from the orange/red wire connector
    on the right ( see image 2 ) the yellow and red lines connect ALL of the dead
    keys on lines 3/4 and 21/22. NOTHING to the right of the orange/red wire
    connector is affected. Only all keys to the left.

    This leads me to believe there is a problem between the orange/red wire
    connector and the first dead key set which is C4 and Db4. It’s like a power
    source or something from the red/orange connector. As you will notice on the
    image, there looks to be a trace issue possibly right before the Db4 contact
    indicated by a light blue line. This trace is in red and connects 22 to 3 if
    correct. The traces to the right on both yellow and red lines look ok.

    Unfortunately I don’t have the proper tools handy here to test that connection,
    but I’m wondering if I solder in a jumper wire if that might be good enough for
    testing. My initial guess is that nothing is getting through from the
    red/orange connector to that row of key contacts. It makes sense to me that
    this could be the main problem and why the sets E1/F1, C2/Db3, Ab2/A2, E3/F3,
    and C4/Db4 all don’t work.

    OR.. the two wires on the red/orange connector are messed up. I’ll check those
    too.

    Hopefully the images and the details I posted here make sense. I think I’m very
    close!

  9. I’m happy to report that the Juno 2 is completely fixed!!

    I had to solder a jumper wire connecting both the red and yellow lines at the
    blue area I indicated on the images. I tried the red connection first and that
    brought back 5 keys. I then went back inside and connected the yellow which
    brought back the remaining five keys.

    It makes sense because the two black lines right above each other were both bad
    so something must have gotten in there and messed up those traces. The Juno 2
    keys all sound great now. I played it for about an hour without a single hiccup
    so other than some further cleaning I think I’m good to go.

  10. I just picked one of these up for ¥5,000 in a used shop. It was really, really dirty but I’ve managed to clean it up nicely. Also, the battery is dead in mine. I have zero electronics experience and I’m wondering how easy it is to change the battery for a non-techie person like me. I’m kind of hesitant to take the lid off, but for now it’s just a preset machine.

  11. I have a very odd problem that i cannot figure out maybe someone can help me. I recently bought a Roland Alpha Juno-2 at goodwill of all places. I found that when I have Chord memory turned off (the light is off) I have a pattern of C1, Gb1, E2, C3, Gb3, E4, C5, & Gb5, (basically every other C Gb and E) all these notes play a horrific chord. I know how to write to chord memory and such but I cant change these notes to play as their true respective note. It is very annoying because i cannot just play a simple chord with any of these notes without it only playing the nasty chord designated to each of these keys. I’m very new to synths, is there anything i can do or is it some sort of defect, i feel like there has to be a solution because the defective notes are in such a distinct pattern.
    Thanks in advance!

    • Hi Kevin,

      My initial advice would be to check the battery and do a factory restore of the Juno 2. You can check inside to see if the battery is still soldered to the main board. If so, then it’s just a matter of short time that it will likely act up and need to be replaced. All sorts of crazy things can happen with a battery on the way out. The factory restore procedure is as follows:

      1) The Alpha Juno 2 must be powered off.
      2) The Memory Protect switch must be off.
      3) While holding down the PORTAMENTO and DATA TRANSFER buttons, turn on the power.
      4) Release the buttons.
      5) The display will show something like “Initlz Funct RAM”
      6) Turn the power off.
      7) Turn the power on.

      The Factory restore “may” be all you need to do. Ruling out the battery and factory restore will then give you an idea if the problem might be in the hardware. Please let us know how it works out for you.

      Jim

  12. I have an alpha juno 2 and since I got it the keyboard never worked at all – I’ve only played it from another midi keyboard. Now that other keyboard is broken and I have no way to play the alpha juno 2 now, so I thought I would have another go at investigating why the keyboard doesn’t work. I’ve opened it up, examined all the internal connections, and everything looks OK. Do you guys have any ideas?

  13. BIG thanks for the factory reset tip! My Juno 2 had a problem of having no velocity sensitivity. Once I discovered that after midi dump velocity started to work misaculously but after turning it off and on the sensitivity was lost again. But after following the factory reset advice velocity now works full time, plus an annoying startup message ‘check battery’ has cleared up (battery was changed). Great little synth!

    BTW, I’ll add another tip. Some of my Juno’s keys did not work when I bought it. I cleaned the contacts with alcohol but that helped only partially. Then I discovered that the rubber contact strips of the keys are exactly the same ones that a Roland’s cheap old midi keyboard PC-200mk2 uses. I had one laying around and replaced my Juno’s rubber contacts and voila – all the keys work now!
    I haven’t only managed to get the aftertouch to work.. any advice on that?

  14. Hi Jim!,
    Great article! I have owned a Juno 1 since it was introduced and recently began rediscovering it from my new interest in ambient music. Such a great little machine! After all these years I have not got a Check Battery message but I looked at it anyway and it is not leaking either, believe it or not! But thanks to you I will know how to fix it in the future!

    Question: Do you know if the reset procedure is the same for the Juno 1 as the Juno 2?
    Thanks again!

  15. Hi, I am a proud owner of a HS-80 and spent the past 24 hours banging my head against a wall trying to figure out how to do a RAM initialization. Of course, I tried the procedure for the alpha Juno 2, but had no luck. Then I went through the list of roland rom reset combos and tried to see if another model’s instructions worked on the HS-80. No luck.

    There are websites that list the reset procedures for Roland models, and they all said “HS-80: no rom reset”. I knew this couldn’t be true, so in the absence of a service manual I just tried random button combinations and … I figured it out!

    Please pass this info onto anyone that will find it useful.

    RAM Init

    1) The HS-80 must be powered off.
    2) The Memory Protect switch must be off.
    3) While holding down the BRILLIANCE and DATA TRANSFER buttons, turn on the power.
    4) Release the buttons.
    5) The display will show something like “Initlz Funct RAM”
    6) Turn the power off.
    7) Turn the power on.

    Version Check

    1) The HS-80 must be powered off.
    2) The Memory Protect switch must be off.
    3) While holding down the MOD RATE and BRILLIANCE buttons, turn on the power.
    4) Release the buttons.
    5) The display will show something like “Ver 4.6h 3.19 86”
    6) Turn the power off.
    7) Turn the power on.

    Copy Preset Bank to Memory Bank

    1) The HS-80 must be powered off.
    2) The Memory Protect switch must be off.
    3) While holding down the BRILLIANCE and KEY TRANSPOSE buttons, turn on the power.
    4) Release the buttons.
    5) The display will show something like “Copy Preset to Memory”
    6) Turn the power off.
    7) Turn the power on.

    These are the only functions I have found.

  16. Hello Jim,
    Is there a vendor that you would recommend for replacement benders for the Alpha Junos? I’m going to look at an Alpha Juno this weekend. And it appears the bender spring has broken.
    Cheers, Jared

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s