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

Step 1 OPEN THE PROCESOR

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

Comments

[rukksi]

Hi Dave, I fried my pedal last week plugging in the wrong adapter accidentally.

This transistor to replace, would one of these do the job...?

http://nz.farnell.com/jsp/search/browse.jsp?N=500005+1002733&Ntk=gensearch_001&Ntt=BC807-40&Ntx=

Do I have to solder in the new one? Who would I get to do that kind of thing? an electrician?

Many thanks
Russ

[Aaron Jones]

Hey Rukksi, did your zoom start working? My zoom just developed the same problem.

[kimera_rei]

i have the same problem as yours. Can someone help me pls.. i beg you. :)
when i turn on the device, it keeps blinking.

[eliemarga]

Hi, I got problem quite a nifty one and I thought there're people with the same problem, it's about the rotary control for on top 3 left to adjust parameters. This problem might be just wearing out but I'm not really sure since I've no adequate skills to target the problem. The problem occurs when you turn the know too fast, even slow turning also produce the same problem, it always goes up even when you turn the knob to the left, this problem does happen frequently which annoy me and also slowing me down when I'm trying to play with the effect.

Does anyone know how to fix this other than replacing the rotary control (what's the proper name btw?), if replacing is the only way could you tell me the spec required to buy the replacement?

[florin_gtrst]

Well, it's probably worn out, I know mine started doing the same. You could just try to lift the rotary's cap and get some contact spray in there. If this doesn't show any improvement, It kind of sucks, you will probably have to replace it.

[eliemarga]

Hi, I did play with mine yesterday and found out that it only happen when I use AC power, problem gone when I use battery power, not sure if it's related with incompatible power source but it's just recently happen, been using the unit for 2 years and did fine before

[darbelouis]

hi

i have change Q4 in my zoom g2,but it still keep on blinking,it does not work.

could someone help me?

[krausgordon]

I have replace the Q4 transistor and my pedal works fine, except for the usb conection (doesn´t after the incident), is like there is no 5v inside the board, where the usb power is. Do you have an idea of what can I do? Also there is sot- 363 "PTJ" I don´t what is it, is the Q500 mark in the board. Thanks in advance

[mr_deadmaxxx]

Is Q4 the only one that needed replacement?
Is your Zoom G2 working like new after replacing Q4?

[zealotifier]

I'm so freakin happy and blessed!, Thanks Dave Fowler for your information, God sent u here!.. my effects works now!,

[mr_deadmaxxx]

Q4 was the only one that you replaced?

[Dave Fowler]

Hi, I have had quite a few queries about the Q4 problem, so thought I ought to post an update here. I'm sorry, but I don't have the schematics for the Zoom G2. My information about replacing the Q4 transistor, was obtained after a bit of arm-twisting, from an engineer at Zoom. The pnp transistor used as Q4 on the underside of the board is a general purpose surface mount type. For some reason, the manufacturers chose to use a low voltage specification device (15V?) - which is part of the problem of its destruction when a slightly higher than normal power supply is used. The package size is known as SOT-23. I just chose one from stock and had no problems. If you are to purchase one (you usually have to buy at least 10 as they are so cheap) I would choose one with ratings at least 30V and 200mA. One such as BC807-40 is rated at 50V and 500mA and costs about 2 cents each. I have also done a temporary repair using a 'standard' TO92 case transistor BC237. These are of course physically much larger, but are in most electronic engineer's stock. If you use this type, check out the pin connections on the transistor data-sheets before connecting. Here in the UK, the transistors can be obtained from RS Components and Farnell. I'm not sure of the situation in other countries- but I'm sure someone can advise. Whatever you use, if you decide to do the work yourself, take great care removing the old transistor so that you don't damage the minute solder pads. Use some form of desoldering braid to remove as much of the solder as possible before attempting to move the connections. Regards Dave

[mr_deadmaxxx]

hi,

im sorry if it took me years to find this comment of yours but im hoping that you can still reply to this comment.

after you had replaced your Q4, did your Zoom G2 worked again?
was Q4 the only one that needed replacement? i mean, no other damaged parts?

[jonr0613]

Hi, my friend bought me a Zoom G2, i tried it for a while using batteries and worked really well, the next day i was so excited to use it again and tried the power adapter that came with it but didn't work when i plugged the power supply and turned on the unit, the only display that i saw was the small or dot like blinking light in the lower right corner of the display...when i check the power input it was only 120VAC, so i guess i busted my G2 :( i tried to use it with batteries again but no power at all....when i tried to reset the unit by pressing store button and then turn it on it shows that there is power "AL" was flashing...and then when i turn it off and on again sometimes it would display the blinking light and sometimes nothing would be displayed....please help....is there any chance that my G2 will be fixed? thanks...

[kimera_rei]

The same problem with my Zoom B2.1u. Can anybody help.. pls pls. pls :)
Thanks.

[popperhopper]

how much was that zoom wah on the side?

[florin_gtrst]

I think i bought it at about 150$, but that was almost 2 years ago

[marcusbradyfoster]

I contacted zoom with this problem and they said they charge 27 bucks an hour for repair, and shipping is about 7-10 bucks on the slow boat ups per way. They said if it looked to require more than an hour they would contact me to have it approved. I wish I could fix it myself but I don't have the skills to pull off what Fowler posted. I located the Q4 on my device and the schematic that the Zoom rep was nice enough to send me. It's about the size of a grain of rice. That's when I decided I was out of my league with fix it yourself. Let me know if you any thing works. Have you tried samuelmf's suggestion?

[Dzevo]

Please need the schematic for Zoom G2.1u what is the DT3 part on the main board 5155A signed only with two numbers 25 also in sot23 case.

Please help

[Dzevo]

end the sch to [e-mail]

[0@078=]

HI I NEED FOTO OF ZOOM G2.1U USB BOARD !! PLEES !

[tommibg]

Zoom G2.1u
Hello all.
does anyone know what type of IC-10 (regulator IC)?
whether the output of this ic was 3.3 volts?
thank you

[jhrawr6]

hello sir,.,. i have a problem,.,. well my ZOOMG1 .its left knob is loose,., and my zoom keeps restarting.,., what could be the problem in my zoom? after a few seconds it restarts T_T ,.,.please help me wat to do/,,.,..,.,

[wdobo]

Hi thanks for the help but does anyone know the value of the r76 resistor (right behind the power jack and also shown very clearly in step 4?

[kwooffindin]

brilliant but does anyone have the switch part number
thanks
ken

[Ezmar]

Yeah, It's sitting dismantled right now.

[florin_gtrst]

I used a regular plier, a multi tool actually ( something like the one in the image ) nothing to fancy.

[Ezmar]

Thanks, Also, the Module Selector knob is loose-ish. What could fix that? And the knobs act weird sometimes, like if I turn them really fast, they go up? shouold I clean the contacts, or what, do you know? I might as well, since I have it all apart right now.

[florin_gtrst]

You should be able to tighten the module knob with relative ease, just pull on the knob button and it'll pop off. Again, i used the small pliers to tighten or loosen the nuts on the front plate. As for cleaning, i think some contact spray would do it. ( The knobs could act weird when rotating them to fast from some possible error when decoding the rotary input's direction... or it could be just wearing out )

[Ezmar]

What do I use to Get the nut off? I can't get it off with any of the tools I have, and It seems like It would have to be a super specialized tool to be that thin around the edges. Anyone?

[florin_gtrst]

sorry for the late reply, still need help?

[alawrow]

I managed to fix my microswitches using the "Servisol Super 10" electrical switch cleaner (the same thing I use on my guitar pots). Basically direct the spray into the gap between the white button in the above picture, and the hole in which it sits). I also sprayed into the gap between the switch and the PCB.

[Jcpstrat]

Thanks alawrow for the idea. I managed to fix my micro switches, that weren't always switching and also my pots, that weren't incrementing, by using "Tuner Control Cleaner & Lubricant" sold by Radio Shack. The top mounted foot switchs were also sticking and making noise. That was fixed using a toothpick to apply a small amount of grease to the shaft, accessible without dis-assembly of the unit.

[soorej]

The peddle switches (the one we need to change), is there any name for it which we can ask in the electronic shop?

[amprepair]

If you can get hold of an old or unwanted VCR, the switches inside the front panel are probably similar. Or any other piece of discarded electronic equipment, TVs, PC monitors, DVD players. Wherever there is a button control on the outside there will likely be one of these switches on the inside.

[florin_gtrst]

 As i said before, i really don't have that electronic shop diversity where i live and don't know if they have a special name by size or part number and such; but i think that they are pretty generic tactile switches.
Sorry for the lack of information in this area, the shops here are a little unevolved... and we don't speak english here so... sorry.

[bawneet]

Hi  !!
I have this unit from d past two yrs.
It has never worked well. The switches are too bad.I have spent a lot for its repair.

Now, I've got a new problem apart from switches.

I am not able to make patches. Whenever I turn the knobs of Gain, Tone & Level , the values doesn't change. Only 2 or 3 values keep coming like SL, 50,1.0 etc..

Any Suggestions Sir..... I would be highly thankful....

[jaxter09]

 Hi.
I'm trying to fix the "effect type" buttons but I can't get the PCB off. I don't understand how to unscrew the outputs, there are no screws?

[florin_gtrst]

 Hi.  there are no screws ( reminds me of Matrix and the "there is no spoon" line  :) ).  if you look at the first image from the last step you will see that  once you remove the knob, there's a nut. you have to unscrew just the nuts from the gain, tone and level  pot's.  

[bernardst11]

I think my Q4 is ok i change it but it doesn't work.  Help me pls... anyone