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zentropa
Gold Member
USA
837 Posts |
 Posted - 03/16/2008 : 09:04:14
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I didn't find a topic like this after digging through a ton of pages and I know there's varying forms of this information floating around in individual threads, but with the search function down, I figured this would be a helpful topic for a lot of people and would save the more knowledgeable posters a lot of repeat posting.
Basically, I'm looking to summarize a bit of an FAQ when it comes to tech failures/breakdowns/etc. and their most likely causes (although I realize that every possibility probably can't be listed) as well as some resources as to go about correcting the problems.
If people who knew the answers to these wouldn't mind posting, I will try to keep this post updated. Please feel free to add questions that should be on here. I'm not an electronics wizard, so the majority of answers here will have to be provided by those more knowledgeable.
Troubleshooting FAQ:
1. Significant drop in sound level is most likely caused by:
I. Certain pedals are known to have a volume drop when engaged.
Known pedals with volume loss:
A. Boss TR-2 Tremolo
Fix: If your pedal was made before late 2006, remove the C4 capacitor and change out the R9 (10K) resistor with a 1/4 watt resistor of lower value. 6.8K should yield unity. Values lower than 6.8K will increase the volume further. TR-2's manufactured since late 2006 already have C4 removed from their design, but the R9 change will still help with volume change. Removing C7 will increase the treble.
II. Aging/failing of components (more specifics will be added here when they are shared by someone)
2. Significant decline in tone quality is most likely caused by:
I. Older pedals had lower input impedances that can cause tone loss.
Fix: N/A.
II. Failing of electrolytic capacitors.
Fix: Replacing the capacitors. Recommended replacements are metalized film (aka metal film) or metalized polyester film capacitors. Tantalum capacitors are known for their "warmth" but will break down over time. Some common electrolytic caps in Boss pedals are 1uf and 0.47uf.
Other common capcitors in Boss pedals that can be upgraded in quality to increase fidelity are:
0.068uf
0.047uf
0.018uf
0.01uf
3a. Significant white noise at any volume is most likely caused by:
3b. Recommended Fixes:
4. Known pedal list with Bleed problems:
I. OD-1 - Bleed Fix mod available.
II. SD-1 - Bleed Fix mod available.
A. J201 Bleed Fix
http://www.indyguitarist.com/temp/sd1-bypass-fix-406.gif
J201 N Channel JFET transistor
0.1uF capacitor
1N4148 diode
B. Laurie Bleed Fix
R18 -> 10K
R19 -> 10K
C11 -> 100uF + 1uf ceramic cap in parallel
Replacement Parts FAQ:
1. The dimensions/threading of a Boss Thumbscrew are:
2. The dimensions/threading of a Boss bottom screw are:
#4 diameter sheet metal screw (aka 4-40) 1/4" to 3/8" long.
3. The dimensions of a replacement rubber grommet are:
Outer diameter is ~1/2"
Inner diameter is ~1/4" to 5/16"
Thickness 1/4"
Groove Diameter is 3/8"
Groove Width is 3/64"
4. The size/values of potentiometers on Boss pedals are:
5. The dimensions and types of switches used in Boss pedals are:
6. The wattage of resistors used in Boss pedals is:
1/4 watt
7. Common diode replacements:
Silicon: 1N4001, 1N4148
Germanium: 1N34A, 1N270
LED: 3mm
8. Capacitor voltages:
Recommended capacitor voltages are 20% higher than the voltage required but you can increase the capacitor max voltage without any side effects as long as they are small enough to still fit into the pedal. Recommended voltages for caps in Boss pedals are 25V or 50V for both size and cost.
Common Mod FAQ:
1. Changing the diodes will affect tone in this way:
The clipping diodes are the diodes that give a distortion pedal its fuzz characteristics. Boss pedals feature asymmetrical diode clipping, which results in a more open tone. removing one of the clipping diodes can change the clipping to symmetrical and "tighten" up the sound a little.
1N4001 diodes are "chunkier" sounding than 1N4148.
LED's are "bigger" sounding but yield less gain than other diodes.
Germanium diodes are smoother sounding than other diodes.
2. Changing the resistors will affect tone in this way:
3. Changing the capacitors will affect tone in this way:
Replacing stock Boss capacitors with higher quality metal film capacitors will increase the fidelity of the signal and reduce noise. Replacing electrolytic caps with metal film will have the greatest effect, but even replacing the poly caps will help increase sound quality.
Increasing or decreasing the value of capacitors can cause tonal changes depending upon where the caps are located. Often the commonly changed caps affect how the highs or lows are rolled off and/or the midrange characteristics as well as the sensitivity of the tone controls on the pedal.
4. Changing the op amp will affect tone in this way:
Other FAQ:
1. Tips for removing velcro/adhesive from pedals without damaging the labels:
I. Paint thinner with a quick washing afterwards. Caution, may remove the serial number if you aren't careful.
2. Tips for removing permanent marker from pedals without damaging the paint:
3. Tips for removing stickers/residue from the pedal casing.
I. WD-40 sprayed on a rag and clean the pedal with the rag. This works very well for removing stuck on foriegn matter and gives the pedal a nice shine. Be careful not to get any on the electronic components.
II. Lighter fluid (for refillable lighters such as Zippos) on a rag will remove many weak adhesives almost on contact.
III. Goo Gone. This requires a soak time but will remove adhesive and residue without damaging the pedal's finish.
Where to Buy Replacement Parts:
Roland Corporation U.S.
5100 S. Eastern Ave.
Los Angeles, CA 90040-2938
323-890-3700
Other Sources of replacement parts:
1. Caps, resistors, diodes, op amps:
www.smallbearelec.com
www.digikey.com
www.mouser.com
2. Pots, 9V Plugs, AC jacks, 1/4" jacks, switches, LED's:
3. Screws, thumbscrews, grommets, springs:
4. Knob covers: |
Edited by - zentropa on 05/30/2008 03:49:23 |
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/17/2008 : 03:55:05
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| added a few updates to this based on a few threads that had answers that sat in my recent memory. i remember reading a few more but i can't recall them off hand. i will do more digging around the board as i find the time. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/17/2008 : 04:02:18
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I just used regular paint thinnner on my new (to me) MT-2 to remove the sticky gunk. No harm that I can see came to the label (I did wash it gently in soapy water afterwards so the paint thinner wouldn't do long term harm).
CAUTION though - on some pedals, I think serious solvents like paint thinner will lift the serial number.
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/17/2008 : 05:21:11
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| i generally use lighter fluid to remove adhesive as it works fast and relatively cleanly, but i have a feeling it might take off the label as well. |
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 03/27/2008 : 02:40:35
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WD-40 I spray it on a rag and clean the pedal with the rag. This works very well for removing stuck on foriegn matter and gives the pedal a nice shine. |
Edited by - pedals 4 pv on 03/27/2008 02:41:25 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/27/2008 : 03:15:25
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quote:
Originally posted by pedals 4 pv
WD-40 I spray it on a rag and clean the pedal with the rag. This works very well for removing stuck on foriegn matter and gives the pedal a nice shine.
A few notes on cleaning pedals...
For the electronics, please never, ever use WD-40 - it kills pots and switches. The only safe thing to use is a specialty "contact cleaner". Here in Canada, we have "Contact Cleaner with Poly Phenyl Ether" form MG Chemicals. It works a treat and won't damage anything in your pedal. Note though that most contact cleaners will leave a film of lubricant on whatever they are sprayed on, so be careful with your aim - I normally put a cloth behind whatever I'm spraying to catch the overspray and drips, then wipe up afterward.
Also note - the film of lubricant is definitely visible - so it is easy to tell if the pedal has been "treated". If you want your 25 year old untouched pedal to remain looking 100% untouched, you probably can't use this stuff.
Laurie.
WARNING ABOUT USING SOAP AND WATER!! I have been using soap and water - the usual "mild cleaning agent" to clean the outside of pedal housings once they are disassembled... I have found to my misfortune that the paper labels inside the battery compartment of MIJ pedals are not waterproof!! |
Edited by - Laurie on 05/14/2008 19:09:08 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/30/2008 : 01:22:41
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Here is what I use for replacement o-rings - just a standard 5/16 grommet from the electronics store. The "slot" is a little tighter once it's installed, but it works fine.
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stinkfoot
Silver Member
Sweden
181 Posts |
Posted - 04/28/2008 : 11:12:39
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quote:
Originally posted by zentropa
A. Boss TR-2 Tremolo
Fix: If your pedal was made before late 2006, remove the C4 capacitor...
Just to clarify, removing C4 does not directly alter the volume. It is part of the LFO circuit, so removing it may change the waveform somewhat (possibly reducing the perceived volume drop of the tremolo effect). But it doesn't control the actual volume, and I personally didn't notice any change at all with it removed (with the "shape" knob set almost fully CCW - it might be different if you use the more square-wave shapes).
quote:
...and change out the R9 (10K) resistor with a 1/4 watt resistor of lower value. 6.8K should yield unity. Values lower than 6.8K will increase the volume further.
I find 8.2K to be about perfect, but that's a taste thing, I suppose. In any case, lowering R9 will let more signal into the op-amp. You can also raise the value of R12 (22K), if you'd rather increase the gain of the op-amp.
quote:
TR-2's manufactured since late 2006 already have C4 removed from their design, but the R9 change will still help with volume change.
Actually, that capacitor is still there. It might be relabeled, though - I haven't looked for it in any of the new ones. The new pedals have a slightly higher output level, so you may not need to alter the volume on them. If you still want to, R9 is 20K instead of 10K, so try 15-18K or thereabouts.
To find out if yours is one of the new ones, look for the "Pb" (circled and crossed over) on the circuit board. The board itself has a slightly different layout as well. You can of course also use the serial number decoder right here at bossarea - the RoHS directive (mandating all equipment sold in europe to be lead-free) went into effect in mid 2006, so if yours is manufactured after that date, it should be one of the new ones.
/Andreas |
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Longordo
Copper Member
Brazil
4 Posts |
Posted - 04/29/2008 : 03:24:19
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[quote]Originally posted by Laurie
Here is what I use for replacement o-rings - just a standard 5/16 grommet from the electronics store. The "slot" is a little tighter once it's installed, but it works fine.
Where can I find these grommets? I'm searching through Internet, but does not find it. Thank you. |
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 04/29/2008 : 04:33:36
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| I get mine at the auto parts store |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 04/29/2008 : 05:11:44
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quote:
Originally posted by Longordo
Where can I find these grommets? I'm searching through Internet, but does not find it. Thank you.
I bought mine from the local electronics store.
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Longordo
Copper Member
Brazil
4 Posts |
Posted - 04/30/2008 : 21:01:57
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quote:
Originally posted by Laurie
[quote]Originally posted by Longordo
Where can I find these grommets? I'm searching through Internet, but does not find it. Thank you.
I bought mine from the local electronics store.
I'm living in Brazil. Can you provide me with a store web adress in your country? Thank you. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 04/30/2008 : 21:06:40
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quote:
Originally posted by Longordo
quote:
Originally posted by Laurie
[quote]Originally posted by Longordo
Where can I find these grommets? I'm searching through Internet, but does not find it. Thank you.
I bought mine from the local electronics store.
I'm living in Brazil. Can you provide me with a store web adress in your country? Thank you.
This is the store I bought them from:
http://www.be-electronics.com/
I think your local hardware store should have them? They are a standard "5/16 inch" grommet.
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Keskin
Copper Member
5 Posts |
Posted - 05/23/2009 : 09:03:56
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It has been a while since the last post here but i need help in troubleshooting my MT-2.
Hope someone can help so here is the problem:
When connecting the battery or power supply to the pedal, everything is fine but after a few seconds, the signal just fades away and gets silent and a bit distorted. This happens even in bypass mode when the pedal is "off".
It does this everytime i dis- and reconnect the power.
To me it seems like some capacitors are discharging and the pedal can`t hold up it`s proper voltage but i`am no expert.
What do you think, which parts could be responsible for this kind of problem?
Thanks
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Edited by - Keskin on 05/23/2009 09:09:34 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/23/2009 : 16:59:19
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quote:
Originally posted by Keskin
It has been a while since the last post here but i need help in troubleshooting my MT-2.
Hope someone can help so here is the problem:
When connecting the battery or power supply to the pedal, everything is fine but after a few seconds, the signal just fades away and gets silent and a bit distorted. This happens even in bypass mode when the pedal is "off".
It does this everytime i dis- and reconnect the power.
To me it seems like some capacitors are discharging and the pedal can`t hold up it`s proper voltage but i`am no expert.
What do you think, which parts could be responsible for this kind of problem?
Thanks
Hi Keskin! If you need help with something, please just use the forum - there is no need to spam members at their PM's as well. I'm also a bit confused about your comment "It has been a while since the last post here" when this was your first post?
Anyway. It doesn't sound like capacitors. it sounds like maybe an opamp. Do you have test equipment?
Moderators - can you please move these posts to the tech thread? |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/24/2009 : 04:04:05
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Hi Laurie
quote:
Moderators - can you please move these posts to the tech thread?
I will have to ask Bossarea-Admin to look into this.
But as far as I am aware, the forum's code only allows me to move an entire thread, & not a post in a thread.
Regards Dr. Bob  |
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Topic |
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Troubleshooting/Maintaining Pedals FAQ
