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Mesjoggah
Gold Member
Netherlands
595 Posts |
 Posted - 07/09/2008 : 06:58:11
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A friend of mine gave me his MT-2 to take a look at, when playing the volume drops and raises. I figured it might be the volume pot but maybe you guys have other ideas about it?
I opened it last night, the volumepot seems to be ok when measured with a multimeter. Unfortunately i think i broke the (foot)switch when disassembling and i cannot figure out why the switch doesn't function anymore, does this happen a lot when taken apart or am i missing out on something? |
Edited by - Mesjoggah on 07/10/2008 07:12:44 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/10/2008 : 15:12:05
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| G'day! Footswitches generally dont break... Can you post pics? (they always help) |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/10/2008 : 15:22:49
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Hi Mesjoggah
The switch used in Boss pedals is a momentary contact type.
it only works while you have it pressed in-down.
It's not a Change-over toggle switch.
That is the function of the Flip Flop circuit, you sometime hear us talking about.
As Lurie said:
quote:
G'day! Footswitches generally dont break... Can you post pics? (they always help)
Regards Dr. Bob |
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/10/2008 : 20:28:13
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I think this picture makes perfectly clear whats wrong.. it was bent at some point and i think it just doesn't work because the plastic knob can't touch the metal strip. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/11/2008 : 16:31:29
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Oh yeah... that's toast. Possibly can to be retensioned, but it would be a pain!
Smallbear sells direct replacement switches.
http://www.smallbearelec.com/Detail.bok?no=36
The ones they sent me when I ordered some were black and identical to the original Boss ones.
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/11/2008 : 23:34:53
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| I'll order a switch, but maybe i need some other parts to make this MT-2 work flawless. So who can give me a little hint to find what can possibly wrong with it? |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/12/2008 : 01:53:13
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G'day Mesjoggah!
Well, it's unlikely to be the volume pot. It MIGHT be one of the buffer transistors (I've seen that happen), or it MIGHT be one of the coupling capacitors (i've seen that too). Or it MIGHT be an opamp (I've seen that too). All the things I've seen haven't beenin a MT-2, this is just the sort of stuff that can cause the symptom you describe.
Really difficult to tell without some measurements... Do you have a multi-meter or a scope?
Does the volume raise and lower in both pass-thru and effected modes? is it just the volume going upa nd down, or is the distortion/tone changing too?
Can u take some pics of the board? (top and bottom)
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/12/2008 : 09:25:36
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I got this pedal from a friend and i only heard it shortly when i met him last week, he told me the volume drops and raises sometimes. Today i played it for half an hour and it works just fine however it's not similar sounding to my own stock MT-2. it 's a little less bassy. I called my friend about my experiences so far and that it seems to work just fine, he said he had opened the box and sprayed contactspray in it, after that it was ok for a few days but then it started again.
I do have a multimeter but don't know what to measure and what values the measurements should be?
Do you always have to assemble the metal housing to test a pedal, cause when i do not assemble the housing i only get noise?
Here are some (actually a lot..) pics:
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Edited by - Mesjoggah on 07/12/2008 09:29:00 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/12/2008 : 10:02:36
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Hi Mesjoggah & Guys
quote:
Do you always have to assemble the metal housing to test a pedal, cause when i do not assemble the housing i only get noise?
This always catches out the inexperienced.
You will have to connect the input socket earth to the output socket earth.
If you look, you will that one of the two sockets only has the active wire.
(The output socket only has the one wire, if I remember correctly.)
I usually just use a Crocodile clip lead between the two lugs on the two sockets.
When the unit is assemble, this connection is made by the metal case.
Regards & Good Luck Dr. Bob |
Edited by - Dr. Bob on 07/12/2008 10:04:23 |
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/12/2008 : 11:56:52
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quote:
Originally posted by Dr. Bob
Hi Mesjoggah & Guys
quote:
Do you always have to assemble the metal housing to test a pedal, cause when i do not assemble the housing i only get noise?
This always catches out the inexperienced.
You will have to connect the input socket earth to the output socket earth.
If you look, you will that one of the two sockets only has the active wire.
(The output socket only has the one wire, if I remember correctly.)
I usually just use a Crocodile clip lead between the two lugs on the two sockets.
When the unit is assemble, this connection is made by the metal case.
Regards & Good Luck Dr. Bob
Hahaha, yes i am unexperienced that's probably why i broke the switch too! but i'm learning from guys like Laurie, forums are a great thing to achieve some knowledge. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/12/2008 : 14:14:37
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quote:
Originally posted by Mesjoggah
I got this pedal from a friend and i only heard it shortly when i met him last week, he told me the volume drops and raises sometimes. Today i played it for half an hour and it works just fine however it's not similar sounding to my own stock MT-2. it 's a little less bassy. I called my friend about my experiences so far and that it seems to work just fine, he said he had opened the box and sprayed contactspray in it, after that it was ok for a few days but then it started again.
I do have a multimeter but don't know what to measure and what values the measurements should be?
Do you always have to assemble the metal housing to test a pedal, cause when i do not assemble the housing i only get noise?
Here are some (actually a lot..) pics:
G'day! Yeah, it's the output jack with one wire. Like Dr. Bob mentioned, the "sleeve" of that jack just needs a connection to the sleeve of the other jack.
OK... The pots on an MT-2 are all sealed so the contact cleaner will not have affected them. It will have lubricated the jacks though. A question - were either of the nuts on the jacks loose when you disassembled the pedal?
There is nothing obvious from the pics.
I've just pulled one of my MT-2 pedals apart for cleaning and I'm looking at the area on your board where there has been some work done (top left in the third pic). This is at the input components - R59 and C43. Any sort of failure here would definitely affect volume. Can you post a pic of that area of the board on the component side? And a really close-up pic on the track side? Thanks!
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/12/2008 : 19:54:13
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Hi Laurie, the jacks were connected firmly, so that wasn't the problem.
i saw something that i am not sure of if it's right this way, de solder from r30 and c24 do collide, is this normal?
I really appreciate your help! |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/12/2008 : 20:56:37
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Super pics! Yep - R30 has electrical connection to C24. No problem there.
Still nothing obvious visually.
You mentioned "i played it for half an hour and it works just fine however it's not similar sounding to my own stock MT-2". How does it sound different? If you set all the controls to "12 oclock" on both pedals and play them one after the other, how would you describe the difference?
Have you actually heard the symptoms your friend describes yet?
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Edited by - Laurie on 07/12/2008 20:56:57 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/13/2008 : 04:41:57
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Hi Mesjoggah, Laurie & guys
The longer I read this, the more I am thinking it might be dirty-dusty-sandy in-out sockets, or a crappy connection lead or leads.
Or perhaps even a dying or flat Battery.
The Vol pot on the guitar, might be on its way out.
Clean up all the sockets with a good contact cleaner, replace the damaged switch, and see how it all goes.
The Pics are great, what camera & model, are you using?
Regards Dr. Bob |
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 07/13/2008 : 08:40:31
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quote:
Originally posted by Dr. Bob
Hi Mesjoggah, Laurie & guys
The longer I read this, the more I am thinking it might be dirty-dusty-sandy in-out sockets, or a crappy connection lead or leads.
Or perhaps even a dying or flat Battery.
The Vol pot on the guitar, might be on its way out.
Clean up all the sockets with a good contact cleaner, replace the damaged switch, and see how it all goes.
The Pics are great, what camera & model, are you using?
Regards Dr. Bob
Laurie - we have to wait.. It is early morning here and don't want to wake up my girl or neighbours (or this might be my last post.. )
Last week i was jamming at my friends house when the volume went crazy so yes i heard it myself.
Dr.Bob - I am starting to think you may be right with the dirty-dusty-sandy sockets, both my friend and i use a Boss ac adaptor so the dying battery is not an option. The volume pot on the guitar should be ok too.
I will clean it up and replace the switch, hopefully it will be OK then.
The pics are taken with a Canon SX100is on a macro setting.
Greets,
Eddie |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 07/13/2008 : 15:51:01
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G'day! One of the most common problems I've found is the input/output jacks being "dirty". These jacks are designed for "telephone" use (hence "phone" plugs) and are designed to have a switchboard operator plug/uplug them 100s of times a day. This usage actually "polishes" the contacts and keeps them clean.
What I always do is soak the jack in contact cleaner and while it is wet, plug and unplug a cable about 10 times, and when it is plugged in twist it left and right a bit. This "wipes" the jack connectors and cleans them. Usually all the crackles and issues disappear. If they dont it's time the replace the jacks. Again Small Bear has equivalents:
http://www.smallbearelec.com/Detail.bok?no=90
and
http://www.smallbearelec.com/Detail.bok?no=91
These aren't identical to the Boss ones, but a bit of detective work will let you figure out how to connect them.
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MT-2 volume issues
