Careful NOT to remove the on-board mini ROM battery as it this the one that keeps the memory settings and gt-6 firmware stored...
First I unscrewed the back metal plate to see the pcbs. Then I cleaned everything up as there were lots of dust and hair inside. The pcbs are held in place by a few chassis bolts and the metal bolt rings of the in/out jacks and pots. So I removed all of these bolts/rings (tens of them....) and spotted the broken switch. The replacement was easy: I unsoldered the old momentary switch and soldered a new one in. The new switch has to be exactly the same as the old one in terms of size and legs/pins.
Then I put the gt-6 together and tested it out to see if everything was working. And it worked!
Tip: be sure to clean your pedal board quite often as it can gather dust and litter. The pedal board usually touches the floor(in clubs/studios/garages etc) where there's dust, litter, humidity, hair and germs. So be sure to clean its base too! Also, spray some contact cleaner on its pots and jacks once you see that some of them start to misbehave.
UPDATE!
Hello!
Sorry I couldn't get clear photos using my phone...
But I could help you change the pot on your gt-6!
The 1st step is to download the proper gt-6 service manual and schematic:
Based on the schematic diagram(page: circuit main 2/2), you need to replace the old pot with a stereo 10Kohm "audio taper" one. You could easily find a stereo (dual) pot on ebay or something. A small metal housing pot will fit in there and will last long(longer than the plastic ones). These pots have 6 pins/lugs.
I used this one (I used the A10K model):
You 'll have to unsolder the old pot and wire 6 short cables in its place on the pcb. That way, you can easily mount/bolt the new pot on the metal chassis of your pedal board.
Τhe 6 pot pins are shown on the layout included in the schematic (circuit board main).
You could use your multimeter on the beeper/continuity mode to trace the C18, C19, C28, C29 capacitor and Ground pcb traces. These are the pcb traces where the 6 pot lugs (or the 6 short cables connected to the pot) should be soldered. See the attached image for a complete guide of "what goes where".
Mind you, I used a 10K pot and NOT a 500K one as pictured:
If you don't feel confident about this, save this mail and visit a tech or an amp repair shop that could help you out.
Cheers,
Thanos
Pics:
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Hi Lulu M,
ΑπάντησηΔιαγραφήThe gt-6 is a very nice board with some great sounds and you should definately repair it!
Changing a momentary push switch isn't too difficult but you should pay attention to some details and fit it correctly in the pcb without breaking anything.
There are lots of bolts and pot/jack rings to be removed in order to get to the broken switch.
The switch you should replace is a simple 2 pin push button, this little thingy:
http://www.ictradenet.com/TL1150AF070Q/
You should also check things like a cut pcb metal trace or contact and resolder it. You need a multimeter with an ohm/ sort circuit buzzer function to check the switch, traces and contacts for continuity!
Cheers,
Thanos from Greece
Hi! i'm italian and i found your site becouse i'm searcing information to repair my gt6... sometimes it seams to get loss of volume so i thing there are some dirty contact into the expression pedal... i have to remove all the chassis to use some contact spray? It's difficoult ? thanks in advance! best regards !!!
ΑπάντησηΔιαγραφήansris
Italy
Hello Anselmo,
ΑπάντησηΔιαγραφήThe problem with your gt6 will probably be solved with a good contact cleaner. You don't have to remove a single bolt! Just spray some cleaner inside the in/out jacks of the board. You could also spray some cleaner on a guitar cable tip and slide it in the in/out jacks of the gt6.
If the gt6 pots are making "scratch" noises when you turn them, you should spray some cleaner on the back of the pots as well. To do that, you need to dissasemble the hole board...
Hi, ur post was really very helpful as I was getting "scratchy" sounds when i was using the "level" button. I used a cologne to clean the back of the level switch and it worked!!!
ΑπάντησηΔιαγραφήThankx a lot!!
Well done Vikas Rao!
ΑπάντησηΔιαγραφήI 'm glad I could help
Cheers,
Thanos
Hi there, Great blog really helpful! Could i ask for your help? I have a couple of buttons not working on my GT6 they are the wah and chorus ones. would you know which type of tact switch i would need to purchase to repair these I am in the uk and can't seem to find anywhere or dont really know what to ask for? Thanks for your time
ΑπάντησηΔιαγραφήCarl
Hello Carl, the momentary switches are mounted on the gt-6 pcb and it's quite easy to replace them. Just unsolder the faulty switches and order the right new switches via ebay.The gt-6 uses 6X6mm switches (normally open). Also, note that there are switches with 2 or 4 legs(dual).
Διαγραφήhttp://www.ebay.co.uk/itm/Quality-Momentary-Tactile-Push-Button-Switch-SPST-Miniature-Mini-Micro-Small-PCB-/180732232689?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2a147b03f1
Cheers,
Thanos
Any suggestions for a hard to push wah on/off button? The wah on my GT-6 is super hard to turn on or off. There doesn't seem to be anything out of place when I take it apart for inspection, it just takes an excessive amount of force to make it click on or off. I was wondering if I should cut off some of the rubber button cover or is there a better way to fix this?
ΔιαγραφήHello!
ΔιαγραφήDiy you check the plastic pad that activates the wah? Is it in good condition? If so, a hard to press button is a usual thing and it means that the momentary switch has to be replaced. It may seem OK on the outside but its internal contact is probably damaged. You should definitely replace this wah on/off momentary switch if everything else is Ok.
Cheers,
Thanos
The switch you should replace is a simple 2-pin push button, this little thingy:
Διαγραφήhttp://site.gravitech.us/Components/BUTT-2/BUTT-2_2.jpg
http://www.amazon.com/6x6x4mm-Momentary-Tactile-Button-Through/dp/B00BXXCD4E
Αυτό το σχόλιο αφαιρέθηκε από τον συντάκτη.
ΑπάντησηΔιαγραφήHi Thanos,
ΑπάντησηΔιαγραφήHaving issue with my old GT-6. the main output level POT which is at the back side of the pedal has broken. Could you help out.
Hello,
ΑπάντησηΔιαγραφήThat's a common problem. You can read my article and order a new Level pot for your gt-6. Then, just desolder the old one and replace it. If you want your gt-6 to look stock, desolder the old pot and go to an electronics part store. There you can find a pot that looks exactly like the old one and replace it. Just be sure to buy the right resistance type pot.
If you're not familiar with electronics, print this article and take it to a qualified technician along with your gt-6.
Cheers,
Thanos
Hi Thanos i have the Boss GT-6 and one of the parameter buttons has ceased to be this item you posted >>> http://www.ebay.co.uk/itm/Quality-Momentary-Tactile-Push-Button-Switch-SPST-Miniature-Mini-Micro-Small-PCB-/180732232689?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2a147b03f1 i take it it will be the 6x6 1mm that i need to get and does it matter if it has 2 or 4 "legs"do i just "snap" two off ? (bit of a noob :/ ) thanks for this article excellent :)
ΑπάντησηΔιαγραφήHello!
ΔιαγραφήThe mini switch you need is the 6X6mm type with 1mm button shaft.
The original boss switches have two legs in the center. Don't buy the 4-pin switch as it will not fit in the right spot on the pcb of your gt-6. Just go for a 2-pin switch:
http://www.ictradenet.com/TL1150AF070Q/
They're fairly cheap as well!
Cheers, Thanos
Hi Thanos,
ΑπάντησηΔιαγραφήMy GT6 pedal switch always on (i reset factory already), so the volume is always on even i adjust a level to 0. Could you help me figure why and how to fix it?
Thanks Thanos
Hello Paul,
ΔιαγραφήCould you please describe the problem with a few more words?
1) Is the volume always set to Maximum even if you turn it down to zero?
2) The power switch in the back. doesn't it turn off the pedalboard?
Thank you,
Thanos
Hi Thanos,
ΔιαγραφήTHanks for your quick reply,
1) Is the volume always set to Maximum even if you turn it down to zero? Yes, i set volume zero but it's still louder
2) The power switch in the back. doesn't it turn off the pedalboard? No, the power switch still work,
Thanks Thanos,
Ok, it seems like a volume Pot problem then.
ΔιαγραφήI would suggest replacing the old Volume pot just like I did in my Gt-6.
Follow the instructions given in this article on how to replace this pot.
You'll have to order a new pot and solder it on the PCB of the gt-6.
If you are not familiar with electronics and soldering, just take the pedal board
to an electronics tech or service and tell them to replace the volume pot for you.
It's not a very difficult job for them and you'll get a professional repair that will
not devalue your gt-6.
Cheers,
Thanos
Thanks Thanos, but 1 stupid question : can you show me where in this article you replace a volume pot, if you have a image for this process.
ΔιαγραφήBy the way, I go to electronics tech nearby I live but no one can solve this problem, I think I will try if you show me really detail,
Thanks so much, Thanos
It's true I did not take detailed pictures while replacing the pot and I cannot take any pics now.
ΔιαγραφήNevertheless, you can still find where the pot is connected by looking at the service manual. It can be found here:
http://www.eserviceinfo.com/downloadsm/41786/Boss_GT6.html
Bare in mind that this is not an easy job for a starter in electronics. If you give the service manual to the technician and tell him to replace only the volume potentiometer in the back, then he will understand right away.
Thanks,
Thanos
Ok, thanks Thanos i will find another electronics and give them a service manual like you said.
ΔιαγραφήThanks again,
Hi, I would very much appreciate your help. My GT6 is giving me a volume problem. When I switch on, I may be on a clean patch on the GT6 then I have to tweak the patch level up to get the desired volume, then I save it. When I switch to another patch I have to tweak the level again on this patch to get the correct volume and save it again. When I go back to the previously saved patch the desired volume level is down by half and so was not saved. I have already stripped the unit completely down and checked for dry joints and cleaned all contacts etc. I am a retired electrical engineer in electronics. Would this be a memory problem? Have you any ideas to solve this? Thank you John
ΑπάντησηΔιαγραφήHello John!
ΔιαγραφήThe "level" parameter is the only thing that is not properly saved? Other effects/gain/eq levels are stored correctly?
This could be a ROM memory issue but that would probably mess with other parameters as well.
There is also another scenario: The level adjust control could be faulty. These controls tend to act up over time and maybe that's why the memory bank has just the output level stored like that.
Did you clean up the gt-6? Dust can cause such issues. Also, I would spray the switches and pots with some oil-free contact cleaner. If you already did these, try to replace the level rotary adjust pot with a brand new one. If the problem remains, you know it's a ROM memory thing and that's something really tricky.
Cheers,
Thanos
hi, i bought a second hand boss gt6 which has a defective "pedal assign" and "output select" buttons...everything else was working perfectly fine until i tried opening it and removed the boards and finally removed the defective buttons which i want to remove and find a replacement part...but when i put everything back in place and turn it on..it didn't turn on, the screen just displayed green boxes...which i think is a problem somewhere in the program...pls help - - - - email add: jdb_61979@yahoo.com
ΑπάντησηΔιαγραφήjasper
I see... You'll have to open it up really carefully and re-check your work. Check every little part for loose connections or broken solder joints. Reflow any broken or "suspicious" solder joints.
ΔιαγραφήI bet there is something loose (cables/connectors/ground/solder joints). If not, the problem might be some damaged chip(s) and this is not something one could DIY-repair...
Thank you,
Thanos
when you removed the main board, did you remove the battery first before detaching the wires?
ΔιαγραφήHello Jasper,
ΔιαγραφήI suppose you mean the on-board ROM battery? NO! I didn't remove this at all! This battery is there to keep the gt-6 memory banks and firmware stored. Once it is removed, the user banks are gone forever and maybe this is why your gt-6 has issues. You should mention this earlier. Check the battery voltage to see if its too low. You can replace it if you're not sure about it. Also, mention this issue to a boss dealer. Maybe they know something more about this battery and how it affects the gt-6 firmware.
Hello guday sir can you help me please. i bought a 2ndhand boss gt6. one of the parameter buttons on the right side is not working. is it defective? or maybe it only need to be clean? thanks a lot. hoping you can help me. :(
ΑπάντησηΔιαγραφήHello!
ΔιαγραφήThe momentary switch under the parameter button is probably defective. It's a common thing in many used pedalboards. Changing a momentary switch isn't too difficult but you should pay attention to some details and fit it correctly in the pcb without breaking anything.
There are lots of bolts and pot/jack rings to be removed in order to get to the broken switch.
The switch you should replace is a simple 2-pin push button, this little thingy:
http://site.gravitech.us/Components/BUTT-2/BUTT-2_2.jpg
http://www.amazon.com/6x6x4mm-Momentary-Tactile-Button-Through/dp/B00BXXCD4E
You should also check things like a cut pcb metal trace or bad contact and re-solder it. You need a multimeter with an ohm/ sort circuit buzzer function to check the switch, the traces and contacts for continuity!
Cheers,
Thanos
sir Thanos you have GT-6 ROM bin. firmware? my gt-6 need to flash..thank's
ΑπάντησηΔιαγραφήHello Rose!
ΔιαγραφήDoes your boss gt-6 turn On and respond to any commands?
If so, you could check the firmware version of your gt-6 by following these steps:
http://www.rolandus.com/support/knowledge_base/view/22636928
Then, you could perform a "factory reset" that will restore all the initial settings:
http://www.rolandus.com/support/knowledge_base/view/22622073
If none of the above works, you can find the ROM firmware updates form this company. You can e-mail them for more information on the subject:
http://www.partheus.com/gtm/gt.shtml
Also, have the rom battery of your gt-6 checked by a technician. This battery is there to keep the rom chip up to date but it can go bad after several years of use.
Cheers,
Thanos
Hi there. I have a GT-6 with an issue. It keeps on rebooting itself every now and then, a couple of times every hour or so. Anyone any ideas how to fix this as I would hate to have to replace this pedal board as it has been superb for me.
ΑπάντησηΔιαγραφήHello Steve,
Διαγραφήrandom rebooting is usually a sign that the DSP chip is overheating but it could also be a power supply issue.
DSP Overheating is also an issue with some modelling amplifiers (e.g. line6 spidervalve). Overheating is also caused by dust accumulation.
Cleaning the inside of your gt-6 with some air-spray cleaner would be the 1st logical step. Use this compressed-air spray with caution as it can freeze the circuit boards.
If the problem doesn't go away, you should probably check the power supply and the electrolytic capacitors inside the gt-6. The electrolytic caps can go bad after a few years. I usually replace these caps with new ones rated for 105oC (Celsius).
http://en.wikipedia.org/wiki/Capacitor_plague
The external power supply (psu) itself could also wear out over the years. The supply voltage might be 14Vac but the gt-6 needs about 800mA of current. An old psu might only supply 500-600mA now.
Hope this helps!
Cheers,
Thanos
Thanos thanks for the reply. I have stripped the GT-6 right down to its component parts and cleaned every little bit of dirt and dust out of it and cleaned and lubricated all the connectors. After re assembly unfortunately it still reboots every so often. I have ordered a new PSU from Roland so hopefully this will cure the issue.
ΔιαγραφήOk Steve, the 1st step was cleaning the pcbs. Then, you have to check the electrolytic capacitors of your gt-6 (the large black ones on Pics 1 and 2). These caps tend to go bad, especially the really large one. You can have them replaced for a few bucks with same spec capacitors: same capacitance in uF, celcius degrees and voltage rating. The voltage output range of the old psu should also be checked.
ΔιαγραφήCheers,
Thanos
Hello Thanos,
ΑπάντησηΔιαγραφήI have a boss GT-6 that when you turn on it is stuck at the "Boss Corporation" start. I replaced the CR2032 battery and tried a reset. Nothing works. Could you please guide me in the correct direction. Thanks.
Hello!
ΔιαγραφήDid you leave the unit without battery and power connected for about 1 hour before reinstalling the cr2032?
1) If so, then the boot problem is probably caused by a damaged EEPROM chip. This is something you can't really fix by yourself. A boss dealer/authorized service is your best bet.
2) A firmware update could also be a solution in case the gt-6 responds to any MIDI signals. If not, we're back to option 1.
I really hope you find a solution to this issue.
Thank you,
Thanos
I took out the battery for an hour then put it back in and did a factory reset. "Factory Reset" came up on the screen, further than I have got before. But now I can't get past this point. I pressed every button and nothing happends. Which one is the enter button.....write? Thanks for any additional info.
ΑπάντησηΔιαγραφήHello, I think it's the "write" button.
ΔιαγραφήHere are some links that will help you out with this one:
http://www.partheus.com/gtm/gt.shtml
http://www.axecentral.com/how-to-restore-factory-presets-on-a-boss-gt-6-10190810.html
http://www.bossus.com/gear/productdetails.php?ProductId=238
-Thanos
can I help you with your gt6 corrupted firmware,,remember me Thanos? i fix my gt6 corrupted firmware,, i flash the chip.. now my gt6 working fine...
ΑπάντησηΔιαγραφήGood evening!
ΑπάντησηΔιαγραφήExcellent help and support already so far, hoping you can help me with my issue. (Me thinks Roland/Boss will charge me an arm and a leg just to investigate it) I've rather come to adore my lovely little processor board, and all the custom banks I've created for it - so obviously, I want to avoid having it recycled.
Boss GT-6 - Recently, right in the middle of a gig, my board suddenly started emitting a constant, high frequency feedback/screeching sound which was unresolved by switching banks or powering off/on. All other gear (cables, amps, instruments) were tested and working perfectly fine.
Any help and/or advice would be greatly appreciated.
Thanks,
Andy
It seems the board is producing an oscillating sound. Do you get any guitar signal at the output of your gt-6 or is there just feedback noise? Did you use another working boss power supply? Do NOT use generic or cheap power supplies!
ΔιαγραφήUsually this oscillating tone/noise comes from Opamps or opamp filters gone bad. The problem is probably NOT with the digital DSP itself. I would replace a few filter capacitors or any capacitors that look suspicious(google "bad capacitors"). Also, check for signs of burnt resistors/opamps/transistors. Make sure you check and clean up the output level pot and output jacks with some contact cleaner. The output level pot is usually going bad and needs replacement: check that as well.
If all seems to be okay, you may have to replace a few opamps (e.g. tl072 or other opamps on the circuit) that are located near the output of the signal path.
Cheers,
Thanos