Erratic Line 6 DM4 DL4 Modeler Switches - Oh, and removing those damn knobs!

[npx]

A friend of mine has both the Line 6 DM4 Distortion Modeler (the yellow one) and DL4 Delay Modeler (the green one). On both pedals there is a stomp switch with the same issue - occasionally when you hit it, it will change to a completely random patch. Obviously this makes for some unpredictable tap-dancing on stage.

What I'm wondering is that since the stomp switches themselves are actuator switches,  (switches with a spring under them that simply press a tactile switch on the PCB) is the problem more likely to be with the PCB switch itself???

I can get replacement actuator stomp switches from Smallbear, but I'd like to be sure that they are the actual problem.

Has anyone else here had this problem and successfully rectified it?

Also, what is the best method for removing the knobs on the pots without damaging anything??? They seem to be REALLY well stuck on there... I heard they are supposed to just pull off.

[ayayay!]

What I'm wondering is that since the stomp switches themselves are actuator switches,  (switches with a spring under them that simply press a tactile switch on the PCB) is the problem more likely to be with the PCB switch itself??? 

That's a good start.  Make sure the springs on the switches are still in good shape and hitting the tactile switch like they should.  Spray a little non-residue electrical contact cleaner in the switches and click them about 50 times.  Doesn't hurt to have that stuff handy anyway.  Get the blue label CRC stuff from Home Depot.   

Also, what is the best method for removing the knobs on the pots without damaging anything??? They seem to be REALLY well stuck on there... I heard they are supposed to just pull off.

What I have had to do is stick a tiny flat blade screw driver down there, and gently pry up.  Rotate each knob fully towards one end, then rock it back and forth a little, gently.  Once they start to become loose, the come of the shaft quickly.  Another approach is to get some adjustable pliers and wrap some felt around the knob, gripping the felt/cloth inside the jaws, and using the same rocking approach to lift up.  Don't squeeze to hard. 

[npx]

Cool, I'll try the small screwdriver trick. Hopefully I can get this thing apart to check the condition of the springs... I already have my contact cleaner handy.

[ayayay!]

The selector shaft is a little different.  The other ones have foam glued to the bottom of the knobs.  Be careful with all of them.   

[npx]

Yeah, I noticed that.

The springs on the actuators all seemed fine, but to double check I swapped the 1st (the one giving me trouble) and 2nd actuator switches and put the board back in. Sure enough, stomp 2 still works fine and stomp 1 is still freaking out, so it must be the switch on the PCB.

While I was in there I noticed that the PCB switch for stomp 4 is a slightly different style to the other 3. It's brown (rather) than black and the button on it protrudes a bit more than the other ones. It also seems to have a more solid "click" sound to it.

Can anybody tell me exactly what these switches are and where I could get them? (A part number would be ideal!  )

Thanks for your help so far, Ayayay!

[ayayay!]

Switch 4 is different because it's a momentary.  A very sucky momentary.   

Man I have no clues, other than to call Line6 and tell them your switch is goofy. 

[npx]

The pics are of the Distortion Modeler... Switch 4 on the Delay is the tap tempo, but all the switches on the distortion do the same thing. (And yeah, that thing may well be SUCK!)

I assumed they were all momentary switches. I'll probably give this a try if I can't find out what those PCB switches are: http://www.diystompboxes.com/smfforum/index.php?topic=74735.0

[omni1]

E-switch makes many types of this kind of smt switch. You can start here;
http://e-switch.com/index.php?contentID=261&type=tact&seriesID=30

[ayayay!]

I attached an external tap tempo for my DL4 using this same method.  It's *way* more accurate than the stock tap tempo.  I just used one of those momentary's from Radio Shack.  Works perfectly.  

[ayayay!]

E-switch makes many types of this kind of smt switch. You can start here;
http://e-switch.com/index.php?contentID=261&type=tact&seriesID=30

Well IMHO, the problem is/can be twofold:  The switch, which is on the PCB, can be kinda flaky.  But add to that the spring actuated stomp, and that it may not be the best way to actuate the tactile switch.  I mean, that's not bad in it's very essence, it's worked for Boss for years.  But this design seems to be much less accurate at times. 

BUT thanks for the link omni1.  This looks like a good replacement. 

[npx]

Thanks for the link omni1, none of those switches had the same leads though, they go all the way through the board.

I think this one looks to be pretty much identical: http://www.futurlec.com/Switches/TACT004.shtml

And to think I placed a Futurelec order not 2 days ago! Grr...

I've seen that external tap tempo mod, it looks like a really good idea.

[Processaurus]

Switch 4 is different because it's a momentary. 

They are all momentary.  That different brown switch was probably a replacement by somebody...

Not to disregard the other switch replacements suggested, but I've used the $.30 yellow Omron switches suggested here when my line 6 pedals have started getting flaky (or were apart for any reason):
http://www.diystompboxes.com/smfforum/index.php?topic=36902.msg262021#msg262021

They are built to be able to handle more pressure, and are a higher quality, more robust switch than L6 used, but will drop right into the PCB.  You can cut the legs off the stock switches to help desoldering.  The Omron's have worked flawlessly in the 3 or 4 of those pedals I've used them in.

Some people have suggested replacing the actuators with the ones from small bear, but I suspect they are identical.  The most common problem with the stock ones (this from a L6 tech I spoke to) is them getting loose and pressing on the PCB switches crooked.  Some lock tight on the nut might work or a lock washer (on the outside of the pedal, to keep the actuator spring to PC board spacing as designed).

Looks like someone else fixed the random patch problem by replacing the switches:
http://www.diystompboxes.com/smfforum/index.php?topic=51473.0

Good luck!

The switch design seems cheesy but that type of tact switch is often rated 50,000 cycles or more.

[npx]

Awesome... Thanks!