Re: B-7971 Clock
- --- In firstname.lastname@example.org, Quixotic Nixotic <nixotic1@...>
> At night I can hear the multiplexed transition effects very very
> faintly 'singing' in the tubes. Presumably this is some kind of
> mechanical noise which can be avoided at night by switching
> off and will extend tube life.John, I have put this noise, and the similar noise you get from
nizies when muxed and pwm dimmed, down to electrocstatic generated
The B7971 segements are quite loose at their ends and where a segment
has been floating at anode potential is grounded quickly a small
force can be generated.
Years ago when I used to repair photocopiers I could watch the charge
electrode wires oscillate due to the AC bias onhe HV supply, either
at the switching frequency or a hamonic of it. Fitting tighter
tension springs was the answer
I've heard it in lage nixies in particular , especially where the
cahodes ae held onto their supports just a little bit too loosely. On
one tube I tipped the tube forward, which rested the cathodes on to
the supports and the noise quieted.
I think it's one of those things. I may try adding pull-mid resistors
to see what the effect is , for a later revision. If the off segments
are not allowed to float up to anode potential but somewhere halfway
insead, when they are grounded only a smaller force can be generated.
Incidentally. I have revised the MK 1 software to reflect the recent
changes I have made to the transition effects :-)
- --- In email@example.com, guus.assmann@... wrote:
> Hello Chris,
> Just now I realise that I forgot to inform you.
> During my holliday, I had some more time and finally managed to get
> correct. So now, the smartsocket with the B7179 on my PCB also worksfine.
> I'll make some more, to get all 7 tubes working.Guus, Thanks for the update.
I haven't been getting the time to do what I need to do either !