Burning AUX inputs

[hchriste]

Hello everybody.

I have a set with two bassdrums, one of witch I tried connecting to AUX2 input on Synthex version 2.8 board. It worked like a charm for about 5 min. Then it suddenly went dead. I verified that the ring input of AUX2 was still working, but the tip input is completely dead. I then connected the bassdrum to AUX3 instead, with the same thing happening. After 5 min it went dead.
My question is what might be burned on the board, and why?
I dont know quite how to verify if the A/D converter inputs are burned or what else to look for.

Hope you guys can help.

Henrik

[Synthex]

Very strange !

If the ring input was still working then the A/D converter inputs are not burned.

What is your bassdrum ?
Do you use 74HC4851 ?

[Firelord]

I dont know quite how to verify if the A/D converter inputs are burned or what else to look for.

Actually, I doubt that the A/D converters are damaged. But it may be the multiplexers (which are luckily reasonably cheap to replace).

[hchriste]

Very strange !

If the ring input was still working then the A/D converter inputs are not burned.

What is your bassdrum ?
Do you use 74HC4851 ?

The basedrum is DIY. It is just one piezo connected to ring of jack.
Yes I use 74HC4851.

[hchriste]

I dont know quite how to verify if the A/D converter inputs are burned or what else to look for.

Actually, I doubt that the A/D converters are damaged. But it may be the multiplexers (which are luckily reasonably cheap to replace).

And how do I verify that it is, other than just replacing them?

[Firelord]

And how do I verify that it is, other than just replacing them?

I am not familiar with the 2.8 kit version of MegaDrum, but Synthex or Dmitri may be able to answer this question. One thing that really bothers me is how can a piezo trigger, passive by nature, "burn" a protected 4851 mux input? What piezos did you use for this bass drum? Anyway, here's why I'd recommend.

- Check the settings in MegaDrum, maybe update the firmware (i.e. rewrite it) and see whether that gets you anywhere; this will ensure that no firmware problem is causing the issue;
- Check the inputs and board for shorts and also for remains of flux if you used any while soldering; this is an unlikely cause, but you can never tell.

[Synthex]

And how do I verify that it is, other than just replacing them?

Change the mux by another one.
But use a "standard" pad ...

[hchriste]

OK. I found out that it is the MUX inputs that are failing. I am still wondering why this happened. The only difference between my two kicks is that the one in question has an extra jack input for placing it in serial with the first kick. That way I figured I could have two kicks on one input. I unsoldered the extra jack and tried my luck with AUX4 input, and so far all is well on that input. Fingers crossed. But I cannot understand why that extra jack should be causing the problems, especially when nothing was connected to it.