Doepfer

> Hi!
>
> I have a A-156 dual quantizer where the top quantizer stops working after being switched on for a few hours when it is in
> the case (P6, not the best ventilation in there). The output is either 0V or +5V. Removing the module from the case,
> cooling it by blowing on it, it starts working almost immediately. Put it back in the case and it soon stops working.
>
> I have tried to identify any parts that gets hot, but none of them sticks out as warmer than the rest, even the regulator
> is not that warm.
>
> Any ideas on this?
>
> Best regards,
>
> Janne

That's really strange and I have never heard from such a behaviour of the module. It could be the processor or the XTAL or the DACs
or ...
To make sure that it's not the switching contact of the trigger signal please check if the module does work with an external trigger
signal when the fault occurs. Elsewise one has to replace one part after the other to find out which of the parts causes the
problem.

Best wishes
Dieter Doepfer

> Hi Dieter,
>
> I will test this as soon as I have some spare time. I rearranged the case a bit to see if it will solve the heat problem.
> The problem only happens for the top quantizer, the lower one works perfectly even if the top one stops working.
>
> Best regards,
>
> Janne

If the lower quantizer works perfectly I don't think that it's a major problem. I suspect that the switching contact of the upper
trig in socket causes the problem. Internal a fast trigger signal is generated which is routed to the trigger inputs of the module
via the switching contact of the trig in sockets -provided that no external trigger signal is applied. If the switching contact does
not work perfectly (e.g. because of corrosion, dust or material fatigue) the trigger signal is missing and the conversion stops.

Best wishes
Dieter Doepfer

> Would heat cause the sockets to malfunction? Since it works fine for a few hours, then all of a sudden stops until cooled
> down a bit.
>
> /Janne

Changing temperatures could cause the socket to "twist" a bit. But that's only a guess. You can find this out easily by using an
external trigger. If the problem disappears it's the socket, otherwise it's another reason. Maybe a cold solder joint. From the
distance a diagnosis is difficult.

Best wishes
Dieter Doepfer