Author Topic: Crimson mesh head trigger plate repair.  (Read 852 times)

Offline ironman187

Crimson mesh head trigger plate repair.
« on: June 24, 2018, 04:05:55 AM »
My new (to me) crimson kit came with a few issues, one of which was a broken trigger plate in the snare. I didn't even try it out before repairing it, I just saw it was broken and assumed it wasn't going to work properly. The previous owner had tried to repair it with super glue I believe.

Things you will need for this repair:
Hair dryer
Drum key
a small, pointy Xacto knife blade
scissors
Contact cement(https://www.homedepot.com/p/DAP-Weldwood-3-fl-oz-Original-Contact-Cement-00107/100195615)
Scotch "Extremely Strong" mounting tape (https://www.homedepot.com/p/3M-Scotch-1-in-x-1-66-yds-Permanent-Double-Sided-Extreme-Mounting-Tape-414DC-SF/203405976)
.05 "non-glare" picture glazing (https://www.homedepot.com/p/Plaskolite-8-in-x-10-in-x-0-050-in-Polystyrene-Sheet-1S08104A/202043333)

If you decide to cut the wire like I did you will also need:

wire cutter
wire stripper
soldering iron
solder
1/16" heat shrink tubing

The first step was to remove the trigger plate, I carefully tried to slice through the adhesive on the foam pillar that the trigger is attached to, it didn't come off as clean as I had hoped, but it did come off.

Edit: I bought a Strike kit soon after this, the internals are virtually identical, I ended up having to replace the plate in the snare on that as well. If you apply heat to the plate with a hair dryer, the adhesive holding it on will become soft enough to remove without tearing off chunks of foam. Simply work the knife between the adhesive and the plate until you can separate enough to start separating the two with your fingers. Also, you do not need to cut the wire, or poke a hole in the foam column. Simply remove the plate, remove the piezo ( heat helps here too), cut a slit it the foam, follow my instructions for making the plate and attaching everything to it, put the piezo wire in the slit, and put the plate back in place.




Next I simply cut the wires to the piezo about 1 1/4 inch from the circuit board instead of un-soldering them on the little circuit board, I just didn't feel like messing with the hot glue Alesis used to pot the solder joints. I then used a small X-acto knife blade to dig between the adhesive and large foam ring, I then pried down on the foam and was able to work the trigger plate piezo wires free.
 

I then took the picture glazing and cut it to roughly the same size and shape as the broken plate, you can cut the glazing with a sharp pair of scissors. The glaze seems so be of comparable thickness and flexibility as the original trigger plate.
 

Using the xacto knife, I then carefully removed the four foam pillars and piezo from the old trigger plate pieces.


After this I used one of the foam pillars as a rubber stamp of sorts by putting contact cement on the bottom of it and gently placed it on the new trigger plate, this left some of the contact cement on the trigger plate, I did this for each pillar location. I then coated the bottom of all three pillars and let everything sit for 15 minutes. I also put the Scotch mounting tape on the piezo and trimmed it. Once the 15 minutes was up, I place all four foam pillars in their respective locations and pressed them into place, I then placed the piezo roughly in the center of the four on the opposite side of the plate.


Next I coated the foam ring with contact cement, it soaked in, so I let it sit for 15 minutes and applied a second coat, the second coat did not soak in. I also placed the trigger plate on top of the pillar to get an outline of where the contact cement needed to go. I carefully applied a coat to that area on the trigger plate and let both sit for another 15 minutes.
 

Apparently, the earlier mesh head pads had issues with the trigger plate cutting the piezo wires, so as a fix, Alesis added two thin strips of foal to either side of the wire, unfortunately, this seems to be the cause of the trigger plate fracturing and breaking. To avoid that issue moving forward, I will be routing the piezo with through the foam pillar instead of through the glue joint. Note that I made sure the piezo wire did not get glued to the trigger plate, but instead angled it away from the trigger plate.


I took a paperclip and poked it through the pillar, then crimped one end unto the piezo wire. be careful not to crimp it too tight, you only need to hold the wire, not crush it.
 

I pulled the wire through, this took a little bit of patience as I had to guide the wire into the hole the paperclip was in, while keeping tension on the paperclip to draw the wire through the foam pillar.


With the wire in it's new routing, I placed the trigger plate assembly on top of the foam pillar and weighed it down for 15 minutes, this may have been unnecessary, but since the foam pillar surface was uneven, I felt it was a good idea.


I used the xacto blade again to get between the large trigger ring, and large foam ring adhesive and pressed down. I was then able to fish the piezo wire through.


This is what it should look like when you are done!


I didn't get a picture of it, but I stripped the wires, tinned them, soldered them together an used heat shrink tubing to avoid them shorting out, put the shell back on
, installed the head, and gave it a whirl. It works as it should! Hope somebody found this helpful.









« Last Edit: July 24, 2018, 07:53:00 PM by ironman187 »

Offline Hellfire

Re: Crimson mesh head trigger plate repair.
« Reply #1 on: June 25, 2018, 10:15:58 AM »
Good repair. To be honest, I'm not a fan of the new Alesis trigger plate design (it is also used in the Strike). I know why they made it the way they did, but it is time to replace it IMHO. 
For more edrum info, be sure to visit my web site at:
          www.HellfireDrums.com                    
My current set-up:  Alesis DM10 and Trigger I/O with modified & DIY pads

Offline ironman187

Re: Crimson mesh head trigger plate repair.
« Reply #2 on: June 25, 2018, 05:51:03 PM »
I have to agree, it doesn't seem very robust and is more complicated than it needs to be. I suppose this was their way of getting around Roland patents? I am a bit puzzled as to why there are now 2 head piezos and trigger plates.

Offline Hellfire

Re: Crimson mesh head trigger plate repair.
« Reply #3 on: June 25, 2018, 09:08:24 PM »
I have to agree, it doesn't seem very robust and is more complicated than it needs to be. I suppose this was their way of getting around Roland patents?

Yes, and Yes.

I am a bit puzzled as to why there are now 2 head piezos and trigger plates.

The purpose is to control the size of the sensor plate (virtually, well sort of). By adjusting the knob you can make the pads two piezo elements act like one big one. which in turn makes it more sensitive. It's really a gimmick the way Alesis implemented it just to get around the Roland patent (I'm speculating).

I'm not 100% sure where they got the idea, but I can tell you that it is very similar to an idea I posted about sometime ago on my own website back in 2009. Here's the link: New Three Zone eDrum Trigger Assembly

That posted assembly sketch was meant as a proof of concept for the dual zone head sensor used mainly to emulate head tracking (or positional tracking). I actually refined it a lot more than what is shown (and built a few protos), but I only posted the proof of concept to keep others from trying to profit off of it.

All Alesis did was instead of treating the two head piezo elements as separated zones, they put the two sensors on a balance control knob. I'm guessing because they realized it's too costly to use three sensors for every drum trigger. Plus that would mean using a new kind of connector jack (I doubt they really wanted to put two 1/4 jacks on each pad).

Again, I have to state I'm speculating.
For more edrum info, be sure to visit my web site at:
          www.HellfireDrums.com                    
My current set-up:  Alesis DM10 and Trigger I/O with modified & DIY pads

Offline ironman187

Re: Crimson mesh head trigger plate repair.
« Reply #4 on: June 25, 2018, 10:09:10 PM »
It's too bad they didn't use both piezos that way, it would have been sick

Offline ironman187

Re: Crimson mesh head trigger plate repair.
« Reply #5 on: July 08, 2018, 09:54:47 AM »
I have updated some of the text, it is not necessary to cut the wires or do any soldering.