[sdiy] Pin 14 on the 3340

[KD KD]

What about a ferrite bead or two on the supply lines just pre 3340?

>> On 18 Jul 2018, at 17:23, Oakley Sound <oakleysound at btinternet.com> wrote:
>>
>> RS > Maybe the capacitor at pin 9 (soft sync) to GND is broken...
>>
>> Unfortunately not. I've got several voice cards that show the same problem
>> and some of them have new components. I have found out a little more. The
>> instability does still occur in positions nearer the power supply,
>> however, it is less obvious. Some specimens of AS3340 do not exhibit the
>> problem. It only happens when the pulse width is less than 50% increasing
>> at the positive excursion becomes thinner.
>>
>> Adding 100nF to each of the +15V and -5V pins does decrease it but not get
>> rid of it. Removing the pin 14 decoupling capacitor seems to help. But
>> adding thicker 0V connections to the board and to the offending VCO does
>> not help. Both VCO1 and VCO2 have the same problem. Using a new issue rev
>> G CEM3340, or original CEM3340, does not exhibit the problem at all.
>>
>> Time to buy ten more rev G CEM3340s I think.
>>
>> Tony
>>
>> www.oakleysound.com