Introduction: How to Repair Your ZOOM G2 G2.1U

Picture of How to Repair Your ZOOM G2 G2.1U

if you are having problems switching through presets or banks , this should probably mean that the micro switches have worn out. this instructable will guide you through a few steps on how to change them.

all you need is :
a soldering iron
a few micro switches
a screw driver



just unscrew the back cover and be careful to put the five screws in a safe place



as this step says, gently remove the foot switch's pcb board and, with caution, remove the cable from the pins; it is not crucial, but it will be more comfortable to solder the contacts this way



remove the defected switch and solder the new one. put everything back in order make sure the switches work before you close the processor. so... if the only problem you had was with the effect switch you're done. congratulations!

for the bank buttons move on to the next step



these buttons are a little more time consuming to change, 'cause of the place where they are mounted, but it's no harder than the foot switches.



first, you have to unscrew the jack inputs and output , then the circuit board can be removed slowly( it's not screwed to the chases )
one you get to the actual circuitry, remove the two screws and turn the cover and remove the knob buttons by just pulling them out. remove the nut and then you can remove the defected buttons and replace them.



screw all the circuitry back on, connect the cables to the pins, check once more for the buttons to work , close the back cover and you're ready to rock with your favorite multi effect processor that responds like the first time you turned it on.

please excuse me if i made any expression mistakes and if i'm unclear in any of the steps; it's my first instructable.


BaseZ (author)2015-02-11

Hello, I donno if this is the right place to post my multifx problem. Well, I have a Zoom g9.2tt and has been using for a year now, bt all of a sudden it ran into problem.

The unit switches on but there is no sound from the unit neither it reads the input signal. I have tried bypass yet no indication on the tuner also tried running audio from the Cubase s/w there is no sound at all. I have checked all the periphery connection, everythings fine. Could someone help me out cause I couldn't figure what's wrong with it.

There is no proper shop who are familiar with repairing guitar processors nearby.

PS there is the image of the G9.2tt CB.

nikiraja (author)BaseZ2017-10-15 for troubleshooting

bruce.liebowitz1 (author)BaseZ2015-03-02

I forgot to mention that if my suggestion does not work, then reinstall Cubase but first uninstall then reinstall. In my experience, a reinstall of drivers usually is the best choice due to fix corruption. I found the manual: They stupidly do not have a troubleshoot section. but you may want to review it to see if there is help. Good luck.

BaseZ (author)bruce.liebowitz12015-04-07

Hello Bruce, thanks for the support. Actually It's not the cubase that I am concerned about but it's my Zoom G9.2tt unit. There is no sound coming out from the unit nor does it detect the input signal. btw the unit switches on and everything works fine just that it doesn't do what it's made for i.e produce sound. Tunner doesn't pick the signal either.

bruce.liebowitz1 (author)BaseZ2015-04-07

You are welcome. More questions, some relevant some not so bare with me. First off, you get
no sounds directly from the unit, are you in the Play mode? To get the sounds to work with the patches in the G2, you have to be in the play mode and the volume can be raised from the lowest setting for each patch, therefore, adjust it inside the unit. If there is no response from your tuner inside the G2, then the software configuration in the unit may be at fault. Is the G2 itself set to mute? Have you recorded your sounds in Cubase and are there wave forms? How do you
have the outputs and inputs set up in the G2? Describe how things are set up. Have you tried to do a factory reset? Sorry for all the question but I need to know more. Is your expression pedal used for volume control? If so, then make sure it is not in the off position. Press the pedal down with your foot slowly to see if you get volume and again adjust the volume in the G2 for each patch that you are using. I hope this helps. Is the output cable to the unit from your guitar connected to the mono or left output? Please me know if any of this helped.

bruce.liebowitz1 (author)BaseZ2015-03-02

I do not know if I can be of help, I'm here on this site to fix my gt 6 boss processor. I read your testimony here and in my experience it is usually an internal volume control that may be turned down or off. Also, check your pre amp to see if the volume control is off, but it sounds as though you covered that base. What drivers do you use for Cubase for audio? Make sure that Cubase is recognizing your sound card. I am not familiar with Cubase but I would imagine there is an audio reference page. If it is not recognized, then reinstall the drivers. I hope this helps. Let me know if it worked.

EdisonCaballes (author)2016-03-21

Hello sir, im having a problem with my Bass effects zoomb2.1u,
zoomB2.1u and ZOOM G2 G2.1U have the same board and voltage regulator?

My voltage regulator is busted im planing to replace it a new one but i cant see the number, mybe you can help me.

ivoaudio (author)EdisonCaballes2017-09-08

Hi, EdisonCaballes.

As far as I can see, it is a 29M33A.

GiuseppeS46 (author)2017-07-19

Hi gents,

My G2.1u pedalboard does non works, I have tried the reset procedure, the display AL flashing etc. but after all disapear and the equipment seems dead!

As per some video on youtube the cause could be the "alimentation" the resistor or the voltage regulator etc. I have noted also a high temperature on the processor surface, and I do not if it is normal. However, I would like to know where I can find or buy the service manual. Some of you can indicate me the number of transistor located on back side of main circuit at the position "Q4" because on main board the number is scatched I can see only the number "5" plus partially the second number 0 or letter C. The transistor at position Q3 is marked: 6C s54

Thanks in advance.

Giuseppe from Italy

chisti (author)2017-01-23

Hi my name is Chisti,i have a problem with zoom

g2.1nu and problem is restart,sometime still hang but now totally display blank.when i press power bottom than response vibrate type sound but display not work.please do something for my processor.

CharlesC178 (author)2016-10-04

Hi my name is Charles , I have a problem with line 6 floor pod plus zoom .
Before is to work well but suddendly these days getting problem from output .when I put on connect my cables and my guitar not coming the signal from out put ..
From out put there is coming harm and buzz noice after but after stop for certain minutes and zoom start to work normally ..than after sometime in the middle start again the same sound from out the noice
, harm the buzz noice pls can you help me any one how to solve this problem....thank you charles

ArjunaidiY (author)2016-09-18

what problem my zoom G2.1u because small red light blinking?

mohdf50 (author)2016-09-04

I want repairing my part zoom g2.. how i cant buy this part.. ???

Replay to my email :

sudipdas (author)2016-03-04

Hay guys! I have this problem with my ZOOM G2 G2.1U.when i start goes to off automatically.and sometime it shows only USB and nothing.plz help me for solve this problem.plz plz plz

cesarquienmas (author)2014-08-21

Hey guys, I have this problem with my g2.1u. The thing is that it has that blinking "bt" message on the display, but I'm using zoom's ac adapter, do you know If I have to replace or change something? Please let me know

MarcoR48 (author)cesarquienmas2015-12-06

You need to replace the R54 resistor:

FelixS18 (author)cesarquienmas2015-10-30

I'm having the exact same problem! Did you ever find a solution?

AldoD2 (author)FelixS182015-11-04

me too the same problem, Help!

martyj2 (author)2015-09-16

My G21u just freezes after a while and you cant change any parameters at all until you restart the unit, and the volume goes and there is no output, any ideas? cheers

Camilad (author)2015-07-16

hello I am repairing one g2 1u need the value of resistor R76, capacitor c68, c67 and datasheet of transistors Q3 and Q4 someone could help me?

kbaurhoo (author)2014-04-14

my zoom g2.1nu wont remains on the menu where its shows G2.1NU Ver:1.03..please help me. I hope u can help guys..thx a lot

ShikiT (author)kbaurhoo2015-04-10

I got the same problem!! On my G2.1KL (Kiko Loureiro Signature), can someone please help us? I already updated everything and still get this type of problem

kirk777 (author)kbaurhoo2014-04-15

did you try to update the firmaware or reset?

kbaurhoo (author)kirk7772014-04-17

still the same... :(

please help

kbaurhoo (author)kirk7772014-04-16

can u please tell me how to reset or update the firmware!! u r very cooperative ...thx a lot man

kirk777 (author)kbaurhoo2014-04-16

Basically you must conect the pedal to your pc, download the firmaware from zoom's web and run the software.
In the user manual you can find the complete instructions to do it, but if you don't have it here is an online version.

lucas.miranda.923 (author)2015-01-23

I'm Of Brazil and need two of this micro switches how the Banks and Rythm ... Someone have this to sell me , send me please... I Need So much of this! Or know where to found this.

LukaszS (author)2015-01-05

You may also try just to refresh the solder. I fixed a problem with my rhythm micro switch that way, without changing micro switch itself.

adhi.artdelight (author)2014-12-15

Hey All, I have Guitar Effect Zoom G1X, I had trouble on PCB mount jack input & phones output, does any body know where I can get the spare part original for ZOOM PCB? thanks

marcus.quaresma.9 (author)2014-07-31

Noite Boa, Sera Que alguem poderia me FALAR quali EO IC10 POIs uma da Minha G2 torrou e ficou Impossível de sabre E quali.

DESDE JÁ agradeço.

marcus.quaresma.9 (author)2014-07-31

Noite Boa, Sera Que alguem poderia me FALAR quali EO IC10 POIs uma da Minha G2 torrou e ficou Impossível de sabre E quali.

DESDE JÁ agradeço.

Stevie421 (author)2014-05-13


I was hoping someone could help me. I was using my G2.1u today into my keyboard with the rhythm section going, no problems at all. Have been doing this for quite a while. All of a sudden, no rhythm section. I don't think I hit any buttons but it is possible.

Nevertheless, nothing I do can get the rhythm to come back. Is there a setting I'm missing? I'm inclined to believe it is the actual button on the unit isn't working because while I can hear all the guitar effects in my keyboard (delay, drive) when I press "rhythm" it doesn't bounce over to that mode and let me modify tempo or pattern. It's not getting to that section.

I don't know how the button could have just broke though. This unit isn't used in performance. I'm pretty gentle with it and use my fingers, not feet.

Please help! I need the rhythm section to work.


Bokey Jocic (author)2014-02-21

Please send me some info about burned transistor Q2 (6CN). Is there any replacement?

kirk777 (author)Bokey Jocic2014-04-15

i think Q2 is the same as Q3 & Q4,
that's a BC817. and replacement that could work maybe BC337. here is the
datasheet ... good luck!

kirk777 (author)kirk7772014-04-23

RECTIFIYING: Q3 & Q4 are BC807 (NOT BC817). because BC807 its PNP polarity, and BC817 the NPN version.

Thus replacement will be BC327 and NOT BC337 in TO-92 case.

Bokey Jocic (author)kirk7772014-04-15

Thanks, works well with the replacement.

kirk777 (author)Bokey Jocic2014-04-15

so you made it? i didn`t try yet because i can't find bc337 far
away from the city, but if works to you i'll buy a couple of them by
internet and wait 'till they come.

jagrae (author)2014-02-13

Hi Guys,

Thanks for all the valuable info. I am a G2.iu owner and I love it, but I have an insurmountable problem for which I find no remedy. ( Even after reading the manual thoroughly .)

At last power up, all I got was a blinking edit light and nothing more. Power modes for battery and DC are functional, but no USB and no coms with laptop.

The juice is flowing through, as you can hear the output connecting with the amp at power up, but no boot up of the Zoom processor occurs.

I have had some problems with power surges and lightning strikes in the past so I imagine this might have toasted something fragile.

This is a great piece of kit and I would hate to lose it. Could anyone please suggest the next step in diagnostics, as I will have it repaired by an expert if necessary ,if possible and affordable.

Could it be a ribbon connector or am I being optimistic?

All The Best . . .

kirk777 (author)jagrae2014-04-15

Have you check the common failure of Q4?
or maybe another transistors like Q2, Q3 Q5 or Q5? If so, replacement
could be BC817 or BC337. I`m sure it works for blinking led, but not
sure about usb power.

Also you must check ribbon conector integrity.

good luck!

kirk777 (author)2014-04-15

kbaurhoo (author)2014-04-14

my zoom g2.1nu wont remains on the menu where its shows G2.1NU Ver:1.03..please help me. I hope u can help guys..thx a lot

krawat2 (author)2014-01-24

my g1xn is not starting
last time when i using it
the display shows "bt" again and again
then after sometime it stops working
i opened it whenever i m trying to start it
the resistor is heated too much
i dont know why?
when i take it to nearest electrical shop it says there is IC problem
plz, can u tell me what is the real problem and how i can fix it?

pzacarias (author)2013-11-06


Someone please, can tell me what's the value of the resistor numbered as R8, that is just next to the Q4 transistor? I have a Zoom G2.1u to repair but someone before me tried and that resistor for somehow is missing.

Best regards.

erichans (author)pzacarias2013-11-16

I did work on Q4. If its the one across its base/emitter leads, its 470 ohms. I remember actually measuring the value. BTW, keep us informed if you solve the "G2 will not switch on" problem. Like to keep in touch so we can share info?

Hope this helps, Erich.

pzacarias (author)erichans2013-12-22


Thank you very much erichans! And sorry I have taken so long to say something.
I have let the Zoom with someone with more knowledge in electronic repair, to try to fix it. It seems that applying the missing resistor on the already replaced transistor (Q4) solved the boot problem. I can't be 100% sure as it needed addicional repairs, because the previous owner done more damages than good, in his attempt to repair the unit. However the unit became bootable again, even if not fully functional, after working in the Q4.

Best regards,
Paulo Zacarias

pzacarias (author)pzacarias2014-01-01


Unfortunately the zoom G2 isn't 100% working, it have a minor problem but very limiting in it's use. The [-] BANK button when in edit mode, behaves like the STORAGE button, in other words when choosing the Drive the [-], instead of come backwards in the list of different drives, makes the display show the current bank and patch number blinking and with a second click saves the settings. Anyone have a clue of can be the problem?

Best regards.

erichans (author)pzacarias2014-01-02

@ pzacarias
Make sure the 20 track Display ribbon connector is properly plugged in at both ends. You get some weird results sometimes if this is not so. Make sure the offending buttons are not sticky. Again weird displays. Were the buttons spray cleaned? Be careful!! For myself, I use any good contact cleaner, spray or liquid, and rapidly exercise the buttons.

Good luck!!


pzacarias (author)erichans2014-01-02

Dear Erich,

Thank you for the prompt response. I will try to do what you said. However I don't think that the problem is in the display, is something wrong with the button BANK [-], or its function because it saves the settings I choose, like the storage button. Strange don't you think?

Best regards.

pzacarias (author)pzacarias2014-01-21


My Zoom it's finally 100% working, the problem were on the 20 pin flat cable that connect the buttons to the main board.

Best regards.

erichans (author)pzacarias2014-01-21

Great to hear!! So it was finally the 20 pin ribbon cable. So glad your processor is working. working!!


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