www.megadrum.info

Hi all
I have finally finised soldering my inputs jack pcbs. I did an piezo to piezo snare rim and connected it to MD but when hit to the snare I got rim voice only I cant get snar sound
what I m doing wrong? pls help me.
regards

Don't get me wrong but first read this: http://www.megadrum.info/forums/viewtopic.php?f=3&t=352

Ok sorry,
I made sythex allinone 2.8 with with inputs jack pcb, I made piezo to piezo diagram of Keith Raper ( http://www.toontrack.com/forum/tm.aspx?m=35166 )
I checked the inputs pcb for an short circuit but everything looks fine. I etched an inputs pcb before and some of the inputs doesnt work before due to bad etching but my snare input was working good with rimshot. But I find a firm here who made the new inputs pcb for me then I soldered jacks and connected the piezos to snare input all I can get a rimshot sound but no snare. I use MDCT 1.6 on an Imac and I use Logic Pro for the software.

Regards.

edit: I see that on Logic Pro that when press the piezo it triggers Csharp1 is it correct value for snare

when I connect a single piezo to the snare jack It has the same result a rimshot sound. But I find something strange= you know that inputs jack pcb made with 2 seperate boards. One which we have usb,kick,tom2,tom4......... pedal inputs and the other is snare, tom1,tom3....... which are connected with an IDE cabel to the main MD pcb. When I disconnect the first one (the one with usb and kick inputs) and Only connect the second one (the snare,tom1 ... one) I can hear the snare sound.
Any idea??

Unplug the cable from your snare but leave it plugged into MegaDrum. Power MegaDrum off. With a multimeter measure resistance:
1) between the sleeve of the snare cable and the ground of the board. What is it?
2) between the the tip of the snare cable and pin 1 of the first 74HC4851 (top left IC in the Synthex's schematic). What is it?
3) between the the tip of the snare cable and pin 5 of the first 74HC4851. What is it?
4) between the the tip of the snare cable and the ground of the board. What is it?
5) between the the ring of the snare cable and pin 5 of the first 74HC4851. What is it?
6) between the the ring of the snare cable and pin 1 of the first 74HC4851. What is it?
7) between the the ring of the snare cable and the ground of the board. What is it?

I m a total dummie about electronics so this is my really first measurement with a multimeter
Pros might found it silly but I have write every little thing i did
I apologize from the Pros again.

Before my answer I realized that when i disconnect the second part of inputs pcb and connect the piezo to piezo to snare input main piezo sounds snare and rim piezo gives rim sound when i hit them
Isnt that the rim piezo works like switch like when i put my hand on the rim piezo, and hit main piezo it sounds rim. In my case two piezo sounds different sounds.

ok my multimeter has 5 options in ohm selection these are: 2000k-200k-20k-2000-200


i choose 200 to make measurements, multimeter shows 1 for default

I dont know the pin numbers so I couldn make measurents If you can explain me the pin oreder I can measure them
so I couldnt answer 2-3 and 4-5-6 questions


Unplug the cable from your snare but leave it plugged into MegaDrum. Power MegaDrum off. With a multimeter measure resistance:

1) between the sleeve of the snare cable and the ground of the board. What is it? 0.35-0.40


2) between the the tip of the snare cable and pin 1 of the first 74HC4851 (top left IC in the Synthex's schematic). What is it?

3) between the the tip of the snare cable and pin 5 of the first 74HC4851. What is it?


4) between the the tip of the snare cable and the ground of the board. What is it? 0.37

5) between the the ring of the snare cable and pin 5 of the first 74HC4851. What is it?

6) between the the ring of the snare cable and pin 1 of the first 74HC4851. What is it?


7) between the the ring of the snare cable and the ground of the board. What is it? nothing changes still shows "1"


I attached a pic of my MD to I draw a circle on a 74HC4851 which I believe the one you mentioned for the measurements.
If you can tell the numbers like from left to right up 1 or down two I can measure the other ones.

Thnk you for your patience

Best Regards

The pin numbering goes like this:

Code: Select all

16 15 14 13 12 11 10 9
1  2  3  4  5  6  7  8


The numbering starts at the "key" of the IC marked as a dip in case of 74HC4851 and goes around it in counter clock wise direction if seen from above.

dmitri wrote:The pin numbering goes like this:

Code: Select all

16 15 14 13 12 11 10 9
1  2  3  4  5  6  7  8


The numbering starts at the "key" of the IC marked as a dip in case of 74HC4851 and goes around it in counter clock wise direction if seen from above.

then
all 2 input boards connected to MD PCB but MD is power off
my meseuraments are:
1) between the sleeve of the snare cable and the ground of the board. What is it? 0.32-0.40
2) between the the tip of the snare cable and pin 1 of the first 74HC4851 (top left IC in the Synthex's schematic). What is it? 0.32-0.34
3) between the the tip of the snare cable and pin 5 of the first 74HC4851. What is it? Nothing changes its 1
4) between the the tip of the snare cable and the ground of the board. What is it? 0.34
5) between the the ring of the snare cable and pin 5 of the first 74HC4851. What is it? 0.52- 0.57 it blinks 120 and then reduces to 0.5 something
6) between the the ring of the snare cable and pin 1 of the first 74HC4851. What is it? 168 or 140 or 33 then suddenly 1
7) between the the ring of the snare cable and the ground of the board. What is it? It indicates a number like 120.1 or 44.2 or 91.5 then immediatly shows 1

ayd01 wrote:

dmitri wrote:The pin numbering goes like this:

Code: Select all

16 15 14 13 12 11 10 9
1  2  3  4  5  6  7  8


The numbering starts at the "key" of the IC marked as a dip in case of 74HC4851 and goes around it in counter clock wise direction if seen from above.

then

1) between the sleeve of the snare cable and the ground of the board. What is it? 0.35-0.40


2) between the the tip of the snare cable and pin 1 of the first 74HC4851 (top left IC in the Synthex's schematic). What is it? 15.3

3) between the the tip of the snare cable and pin 5 of the first 74HC4851. What is it? Nothing changes its 1


4) between the the tip of the snare cable and the ground of the board. What is it? 0.37

This tells that the Head input of the snare is shorted to the ground. Obviously you will never get the head signal if it's grounded. You need to find where it is shorted. I'm guessing that your jacks are "switched" jacks and you soldered the wrong pins at least on the snare jack.

5) between the the ring of the snare cable and pin 5 of the first 74HC4851. What is it? 12.4-12.6

6) between the the ring of the snare cable and pin 1 of the first 74HC4851. What is it? Nothing changes its 1


7) between the the ring of the snare cable and the ground of the board. What is it? It indicates a number like 120.1 or 44.2 or 91.5 then immediatly shows 1

It's a capacitor effect.

Hi dimitri
I m sorry but can you read my last measurement message which all my measurements are in "red font"
When I was doing the measuring I realized that I didnt connect the 2 part input pcb so I connected it and do the measurement again
I guess while I'm editing my message you read the old version.

It will be a burden but pls read my last measurements.
regards