Crosstalk problems on some inputs

[coralgol]

Hello!

I had six inputs in Megadrum(J1-J6). I expanded the inputs from J9 to J14. If I connect a pad to the new inputs, the VU Meter shows me two 2-3 trigger signals, even if hit the pad lightly.
The Pads are not too hot. The crosstalk problems only appear with the new inputs. I read some threads about it, but they didn't help me. I can increase the crosstalk option just to the value 3 (Firmware 20100516). Multiplexers are 4051. Could it be a Hardware/Software Problem?

Thank you

[dmitri]

Multiplexers are 4051.

And what did you replace Bat85 diodes with?

[coralgol]

Multiplexers are 4051.

And what did you replace Bat85 diodes with?

Why replace? All parts are the same as in the schematic.
I was looking for errors on my analogue board, but I haven't found anything.

Edit:
I noticed that when I power up Megadrum, the LED is on, all the time, until I hit a pad. In the past, the LED was dark after a few seconds.

[dmitri]

Multiplexers are 4051.

And what did you replace Bat85 diodes with?

Why replace? All parts are the same as in the schematic.
I was looking for errors on my analogue board, but I haven't found anything.

In this case:
1. Some bat85 diodes soldered in reverse.
2. Some bat85 diodes not soldered properly.
3. Some bat85 diodes are falty.
4. Some bat85 diodes are not in fact bat85 diodes.

[coralgol]

In this case:
1. Some bat85 diodes soldered in reverse.
2. Some bat85 diodes not soldered properly.
3. Some bat85 diodes are falty.
4. Some bat85 diodes are not in fact bat85 diodes.

Hi,

I checked all bat85 diodes. They are all alright. I replaced the 4051 ICs with newer ones, but they seem to be alright, too. What could that be?

[dmitri]

In this case:
1. Some bat85 diodes soldered in reverse.
2. Some bat85 diodes not soldered properly.
3. Some bat85 diodes are falty.
4. Some bat85 diodes are not in fact bat85 diodes.

Hi,

I checked all bat85 diodes. They are all alright. I replaced the 4051 ICs with newer ones, but they seem to be alright, too. What could that be?

If you are absolutely sure about bat85 diodes then I can only suspect bad soldering: hair thin shorts, excessive flux and etc.

[coralgol]

In this case:
1. Some bat85 diodes soldered in reverse.
2. Some bat85 diodes not soldered properly.
3. Some bat85 diodes are falty.
4. Some bat85 diodes are not in fact bat85 diodes.

Hi,

I checked all bat85 diodes. They are all alright. I replaced the 4051 ICs with newer ones, but they seem to be alright, too. What could that be?

If you are absolutely sure about bat85 diodes then I can only suspect bad soldering: hair thin shorts, excessive flux and etc.

Ok I will check again. Are you sure that this problem causes only the analogue board?

[dmitri]

Ok I will check again. Are you sure that this problem causes only the analogue board?

No, I'm not sure. You may also have bad soldering in the Digital board or in the cable connecting the boards.

[coralgol]

I found the problem, the cable connecting the board had got a short
I would never expect something like that

But thank you anyway.