Roland MC-303 Teardown and Repair

[@mikaras]

Thanks for this very informational video. Just bought a 303 used which has issues with the 'hh'/part 2 button and with your video as a reference it will be very easy to replace. Another vintage unit escapes the dumpster! :-)

[@reddenstudio]

Great video! I have to replace my bass pot on the jack board and now I understand that is going to be one of the easiest to replace since that board is trivial to remove. Thanks for the MC-303 lesson!

[@warmrollsforthetable]

I love my 303! I ordered the switches and it looks fairly easy to replace! Awesome videos dude.

[@LincolnSward]

@bradthx would you mind sharing the values of the other pots. I'm trying to find them because my resonance and envelope pots are starting to go. Great video! Thx.

[@andrewverran3498]

Hi, do you know of these Panasonic tactile swithceh/buttons are the same as those on the Roland MC505, ? and what would you use to clean them ? Contact cleaner? Thanks in advance.

[@spijavcaveaceslav207]

Hello, very helpful video! Can you please specify part number of volume potentiometer and micro switch on this device, thank you in advance.

[@matatias]

Thanks! I just got mine today and decided to tear it down to apply some contact cleaner, and I think I messed up the effects potentiometer. Will need to open it up again, maybe.

[@thesoftdistortion]

Hi, I've just put my 303 back together after re-soldering the pot connections on the board (volume pot had come away from the board). I am now getting ERR 2 and ERR 3: MIDI Cable Connections / Too many MIDI messages at once when playing via MIDI. Only certain notes will play and it's the same ones that don't all the time, while some that do are intermittent. They all play fine from the front panel. Could it be one of the ribbon cable connections? I have tried more than one MIDI cable so it's not that. Any suggestions?

[@iancabott]

My MC 303 doesn't turn on!! I have tested the power source and it has power OK, but I get the impression that there is a problem with the on/off switch. I can't find an electrician who wants to take responsibility for checking it (too old fashion machine!) ....... any tips? or video you can recommend?? thank you very much!!

[@N8oRMusic]

Great video. Thanks mate. I was wondering if there is anyway to expand the outputs on the 303 eg. turn the headphone jack into output 3&4. Would be great to process drums externally seperate from the synths. Cheers.

[@Robert13b]

Do you have the binary files of the mc-303 ic7 and ic8 ROM version 1.03?

[@graxjpg]

how can i replace one of the button switches where the boards pad has come off? its the stop button of all things

[@nortagnan2135]

Great video man, can I ask what was the tool you used to remove the ribbon leads from the boards, it looked quite specific

[@bradthx]

I was using a dental tool, although any small screwdriver will work. You jut need to lift the white clips up on each side.

[@alienproberecordings]

hi,wondered if you knew if i could use the stereo (twin connection pot) on one of the 3 pin locations just by bending out the un used pins? As the 6 pin is a volume pot and the rest are data i assume....or volume is data too if this matters??. will the linear/audio classifications of potentiometer's matter? i'm sort of new to in depth circuits so still learning. thanks

[@JB61264]

More recently, they keyboard on my MC-303 stopped producing sound when I depress the keys...they all light up when i play a sequence, but don't produce a sound. Any thoughts on what I should look at to fix this?

[@djbuttlicker1521]

Hey! Do you know which part I need to repair the select button/switch?

[@dirkbinnenbose3683]

Hello nice Video. On my MC303, the IC8 burned out, it have on PIN 8 to 4 = 9,95 V! The output is not stereo! Do you have a tip for me?

[@alienproberecordings]

do you think that ram is upgradeable and if so,what benefits? i have heard there's no upgrades or mods other than the firmware and using a switch for the sustain mod to hold notes

[@warmrollsforthetable]

I swapped out all switches w/o incident, not sure if I will swap the keybed switches they seem okay and I use a midi keyboard anyway. Thanks for the help dude!

[@chrishartnett8652]

awesome man, thanks for this my newly purchased 303 arrived with the same prob, i've goten away for a week with tapping it to hold it in a certain position but now i've got to the point where I need to replace. I have basically zero electrical knowledge... is the only tool i need aprt from screwdriver is the soldering pen? Thnks!

[@pietromoko]

I have a background noise on my Mc 303, which can be the problem? Thank you!

[@phile3741]

Mine is doing some sort of 60 cycle hum thing after sitting for a few months, and having no prior issues.

[@claud_b]

Thanks for the nice explaining :) My 303 has some problems with the micro switches.. I think about replacing them!

[@Pazaluz]

i'm borrowing one at the moment from a friend. Has some problems with the audio jacks. Headphone jack only gives left signal, lots of static too! might just need a cleaning

[@uiliumpowell4684]

I have one of these with the same exact problem with that volume knob but also I can't seem to find the right power adapter for it or there is something wrong with the power plug.

[@tenmillionvolts]

It needs a 9v negative centre type. It must be negative Centre on the plug or you could damage it

[@My_man_G_UK]

#bradthx. How do you test the tactile switches as my *enter*, *exit* and the rest of the play buttons don't respond. I've test each switch by either side, pressed button, using a multimeter. But trying to find their connection after ic4 - ic1. I have the schmatics but still, I get lost? #helpabrother? 🙏🏾

[@johnlawson3014]

I thought the part number on the mouser page in the video was the actual number and ordered it, trying to find the right number now but its harder than I expected.

[@yangtze2000]

Thanks for videoing your adventure inside this MC303! Quick question please: I presume updating the firmware to v1.03 requires changing out a ROM chip? Does that require soldering, or did they make things any easier knowing there would be updates?

[@alienproberecordings]

im about to do mine (1.02 to 1.03) and i think its just pop them out if roland put those grey adapters you can see in the vid the 2 long chips on the left but if they didnt then its soldering... i brought these and followed the info and service manual www.ebay.co.uk/itm/Roland-MC-303-MC303-V-1-03-Firmware-OS-Upgrade-Eprom-Update-Latest-Version/164639095172?hash=item2655413984:g:SJwAAOSwkqFf~K3b

[@yangtze2000]

@@alienproberecordings fab, thanks APR! I'll cross my fingers about the adapters...

[@alienproberecordings]

@@yangtze2000 ive just checked and mine has them so i guess if you have 1.o2 rom then they may have fitted them.so hopefully just pop them off!!

[@yangtze2000]

@@alienproberecordings thanks for the info!

[@jedtrucker]

The volume pot you need: RK09L12D0A1W. You won't have to hacksaw it, it's exact to the original spec

[@infesticon]

Do I have to worry about leaky caps disolving the board or are the capasitors ones that last ok?

[@spindlenine]

excellent video. I need to take my MC-505 apart in order to whiten the keys, and was unsure how to do so but now that I’ve watched this I have a pretty good idea what to expect. Your tips on propping up the case and not flipping it upside down so the keys stay in were especially helpful. :) Do you have any recommendations for whiteners for yellowed keys? Looks like a ziploc bag, some peroxide, and a stint in the sun is all that’s required. Do I need to treat the keys with anything after washing off the peroxide to prevent brittleness? Thanks in advance for any tips you can offer.

[@spindlenine]

I also meant to ask: any tips for removing the “chiplet” keyboard keys that are apparently attached to the front panel board?

[@chrishartnett8652]

dayuuum, i ordered the part you showed in the screenshot, shipped from texas to new zealand, just desoldered and realised that the pot is single and not dual gang! bugger, that was a waste of money :( clearly i am a noob for not realising this myself. this is a very helpful video but maybe update to the correct part? I think I've found the correct part and it is RK09L12D0A1T... anyone agree. wanna make sure i get it right before shipping again. thanks

[@chrishartnett8652]

i can confirm that RK09L12D0A1T is the correct part. I reordered and have done the repair. now i have some spare pots if the single gang ones go bad!

[@chkchrycla]

@@chrishartnett8652 Did almost the same thing...now I'll wait for the correct part.

[@phile3741]

@@chrishartnett8652 MIne 303 is producing a low hum noise. Would you know if this related to the volume pot/

[@superlowblue]

I noticed that the power adapter in this video doesn't look like original. Mine has died and I don't want to fry my 303, do you know where I could find the right adapter?

[@bradthx]

It just needs 9V at 500mA or more, center negative. Basically any 9V adapter will work, if you can't find center negative, just cut the cord and swap the wires.

[@recycology5468]

Very handy video thank you for the upload!

[@yogitkm9961]

Se puede usar un potenciómetro alternativo?

[@bbr7415]

Hei i love youre videos i learned so mouch from them i was wondring if you no the encoder parts nr i have cheked the roland servise manual and the part no is not in mouser catalog her is the part no ENCODER EVQ VEM F01 24B if you can help me tanks

[@GrabTheBatKiller]

Could you share the model number for the 1/4 inch output jacks

[@fighterz9995]

Where did you order your parts from the knobs

[@yourabuttliche6830]

Need help replacing the microswitches... I ordered them from digikey... I am okay at soldering... should I seek out a professional?

[@bradthx]

The board is a single layer board so is pretty easy to replace. Can't mess much up, get some solder wick to remove. Thanks for watching!

[@rcbodyshopfr]

found years ago a MC-303 but never managed to have sound from it. All functions seems to work but no sound both from headphone or line out. All ribbon leads are in place, maybe amplifier board is faulty but no idea to check this without special tools or knowledge. if someone managed to fix it. before going to recycling.

[@bbr7415]

Where can i order the pots and what nr is it

[@cubikvolume4403]

My software version is 1.01 but i can't find the 1.03 update anywhere online

[@hardhouseire]

U have to buy an eprom chip with the 1.03 firmware preinstalled and replace the one on your board (taught about it but hardy worth it)

[@djflexmk2]

*AWESOME BRO* !!! ❤😁👍🏻✊🏻🖖🏻

[@chrisclark8871]

Did you say Pandasonic @ 14:32 hehe

[@bradthx]

Lol, it sounds like it. I was probably tired that night.

[@My_man_G_UK]

Guys.... Found a page for you!!! archive.org/details/RolandMc-303GrooveboxServiceNotes/page/n3 😮😮😮😮 Part numbers are in here.

[@JayKaufman]

I bought one of these new back in the day and paid an absurd amount for it. I absolutely loathe this machine. It's horrible! That said, a friend had one with the exact same problem and I got inside of it and those damned buttons were an absolute chore to get to sit right. I think I took it apart three times before I got everything to sit right. The only place one of these belongs is with a kid who's wanting to mess around. Otherwise, they really are one of the worst things Roland has ever made!

[@uiliumpowell4684]

Why don't you like the 303? Because it isn't good at assisting you as a musical performer or as a musical composer?

[@JayKaufman]

@@uiliumpowell4684 because it's a pile of junk. It sounds like garbage. The PCM samples are all very dated sounding. The filter is crap. They only had a pair of stereo outs. Arranging on it is a nightmare. MIDI implementation is downright awful. The DSP FX aren't chainable and sound like they were made by a deaf person. Shall I go on?! I have plenty more to complain about on it. It's just a terrible machine. They marketed it as a rave in a box and it's more like a jack in the box - a joke. It was a complete waste of my money when I paid $1,899 CAD (plus tax) when it came out in 199whatever it was and got sucked in by the marketing. I sold it within a year at a $900 loss because they'd come down in price so much. Why the price drop? By then the cat was out of the bag that Roland had made a dud. It's still a dud. The hate I have for this machine is real and has left me traumatized all these years later!