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paisleyfender
Bronze Member
Germany
70 Posts |
 Posted - 05/31/2006 : 16:40:46
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Hello everybody,
I recently acquired a CE-3 Chorus, which sounds quite good to my ears, warm and not so "80ies" as some stated on harmony central.
But the pedal has one problem unfortunately:
when switching it on or off, no difference, there is a loud popping noise heard through my guitar amp (peavey classic 30).
I tried different power supplies, 9V battery, and a different amp, doesn't help.
I also opened the pedal and shortened the switch lugs to see if it's a mechanical problem, no, it must have something to do with the electronics.
Can anyone help here? Did anyone have the same issue, or maybe can provide a service manual and schematic?
Any help would be highly appreciated! |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 05/31/2006 : 21:15:15
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It could be that the switch is dirty.
Maybe try some contact cleaner and work the switch a few times and see if it gets better. |
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stahlhart
Platinum Member
1318 Posts |
Posted - 05/31/2006 : 21:58:57
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The difficulty here is that the audio signal doesn't pass through the switch -- if it's the usual flip-flop circuit, then it's firing an FET's gate somewhere relatively close to the pedal's output. That switching is supposed to be silent, which concerns me.
An audible pop suggests to me a capacitance buildup somewhere that's getting discharged into the signal path, probably as a consequence of the flip-flop changing states. But where/why/how?
C.K.
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stahlhart
Platinum Member
1318 Posts |
Posted - 05/31/2006 : 22:08:55
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Unfortunately I don't have a CE-3 schematic to reference.
With the following setup: guitar -> CE-3 -> amp , and the volume on the guitar turned all the way down, is the noise apparent when the pedla is switched on and off?
C.K.
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 05/31/2006 : 23:42:53
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True, Stahlhart. I didn't think that far.  |
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paisleyfender
Bronze Member
Germany
70 Posts |
Posted - 06/01/2006 : 01:21:14
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The noise is also there if I only have the pedal connected to the amp, so it doesn't make any difference if a guitar or other effects are involved.
Couldn't it be that some capacitor is damaged and therefore the levels in the signal path are not as they are supposed to be, so there would be a level difference between on and off states? |
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Austen
Bronze Member
50 Posts |
Posted - 06/01/2006 : 01:46:57
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That's right..there's dc finding it's way into the circuit somehow.
Who ever heard of component failure (other than BBDs) with boss pedals?
It's pretty rare.
Look for the most obvious first...stray wire strand/foreign matter on the board, then check each and every wire connection, clean each jack.
It's much more likely one of these.
Cheers |
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stahlhart
Platinum Member
1318 Posts |
Posted - 06/01/2006 : 02:30:48
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quote:
Originally posted by paisleyfender
The noise is also there if I only have the pedal connected to the amp, so it doesn't make any difference if a guitar or other effects are involved.
Couldn't it be that some capacitor is damaged and therefore the levels in the signal path are not as they are supposed to be, so there would be a level difference between on and off states?
It's really difficult to try and zero in on the problem without a schematic diagram -- I looked at the CE-2 circuit, figuring that it might be similar to that, at least the switching circuit anyway.
http://www.freeinfosociety.com/electronics/schematics/audio/bossce2.pdf
If this were the CE-3, the trouble would be happening somewhere in the vicinity of Q9. A positive voltage applied to the gate (that's the lead at the bottom connected to the diode D4) switches the transistor on, and the path from R22 to pin 2 of IC1 is completed (it's essentially resistance between the other two FET terminals added to R22 here). So that's the "wet" (delayed) signal coming through there, and then it gets mixed in in IC1 with the "dry" path coming through R21.
So something similar to this is probably happening in the CE-3, but it's not really possible to speculate further -- as far as specific components -- without seeing the CE-3 schematic.
C.K.
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paisleyfender
Bronze Member
Germany
70 Posts |
Posted - 06/02/2006 : 16:51:19
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Thanks everyone for your efforts!
So I looked for any debris (nothing found), cleaned the pedal, jacks, switch, and the whole pc board, no difference, the switch noise is still there.
I also suspected one 1 uF capacitor which looked a bit brownish, and replaced it with a new one, but this also didn't help anything.
So any more ideas?
Doesn't anyone have the schematic? |
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stahlhart
Platinum Member
1318 Posts |
Posted - 06/02/2006 : 19:07:36
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I'm willing to bet that if the pop is coming from a capacitor discharging, it would be one of those 1uF stage coupling electrolytics -- that would probably be a large enough stored charge to create the pop. Only question is which one, and why -- to me it doesn't seem like a bad capacitor, as I would expect it to do just that sort of thing if it's a healthy component -- It's probably something else in its vicinity giving it a path to discharge that it would not normally have (otherwise Boss pedals would not have silent switching at all).
But unfortunately without a diagram I think we're all at a loss to troubleshoot it further.
You're probably not going to believe this, but many years back, when I used to have an Electric Mistress and it broke, I traced out the circuit myself and drew up a schematic (I still have it, too). I needed to create my own schematic diagram in order to fix it, which I ended up doing successfully. It's a real pain in the butt -- you have to do it one part at a time, following the traces on the circuit board, and then rearranging it all on paper to look correct and make sense to follow. It was a few weeks of work. No internet back in those days.
Seems to me that your alternatives at this point are to (a) acquire a schematic somehow -- perhaps you could order a service manual from Boss, or I see one here http://www.rangeraudio.com/manuals1.htm ...or (b) have it serviced (though you might be able to find another CE-3 for what the repair work might end up costing).
C.K.
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steve1234
Copper Member
Canada
15 Posts |
Posted - 06/06/2006 : 05:30:31
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| I Use WD-40 On amp knobs that sound scratchy and on Boss pedals I know it may sound odd but it worked for me. Using the red straw with can works the best. |
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paisleyfender
Bronze Member
Germany
70 Posts |
Posted - 06/06/2006 : 18:29:31
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Steve1234, I've cleaned the switch (and the whole pedal) already, did use WD-40 also, didn't help a bit.
But now I've got another problem because I opened the pedal quite too often:
One lead from the pc board to the jacks got loose, and now I don't know where it goes.
It's the plain white lead that starts on the short side of the pc board.
Anyone who could help me out of this? |
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stahlhart
Platinum Member
1318 Posts |
Posted - 06/06/2006 : 18:46:25
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If it's white and it goes to one of the jacks, then it's probably either the input or output signal line. The ground wires are usually black.
The input jack also functions to disconnect the internal battery when there isn't a cable plugged in -- but it does so by disengaging on the ground side.
What you'll need to do is locate where there should be a wire tied to one of the end pin conductors on one of the two 1/4" jacks. Take a look at the ends of one of your cables -- see how it has two metal surfaces separated by a plastic or phenolic insulator? The tip at the end is for signal, and the cylindrical part that goes back to the plug handle is shield ground.
So you'd be looking at the input/output jacks, and the terminal that leads to the contact for the end pin on one of them is probably where a wire is missing. See if you can locate the presence of solder on one of the terminals where a wire isn't present.
When I get home tonight I'll take a look inside a few of my pedals to see if any have an equivalent wiring color scheme -- unless someone else here has a CE-3 (I don't) and could compare directly... Bossarea, have you got one?
C.K.
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 06/06/2006 : 19:38:43
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I can take a picture of mine when I get home from work a bit later.
I have been looking for a CE-3 schematic myself without luck. I just wanted to know how much different it is from the CE-2. Maybe I'll take some time, sit down, backwards engineer it and draw a schematic. |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 06/06/2006 : 22:12:51
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Unfortunately I got a little too close so it's a little out of focus.
Brown, yellow and 2x black go to input
The white from connector 5 on the PCB goes to output A
The white from connector 6 on the PCB goes to output B |
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stahlhart
Platinum Member
1318 Posts |
Posted - 06/06/2006 : 22:43:25
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Oops! I forgot that this one had stereo outs...
C.K.
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Topic |
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CE-3 switch makes popping noise
