Jeff Thomas GPSII

[David Glover-Aoki]

I have a Jeff Thomas GPSII clock, and the firmware in it is quite old. I had always intended on getting a new chip from him, but of course that is no longer possible.

Is there anywhere else I can obtain/purchase a chip with the last known firmware in it?

On a related note: I'm vaguely interested in buying a new clock in the near future. Are there any recommended vendors who match the quality of Jeff's clocks?

Thanks.

[Jeff Walton]

Regarding your thoughts for a new clock – for a larger tube clock that is well designed and supported, I would look at the IN-18 Blue Dream from Nocrotec.com or the Spectrum Series large tube clocks from PVElectronics.co.uk.  An advantage of PV is that you can purchase the electronics and cases from one single source.  The Blue Dream has to be purchased through a couple vendors – I think due to regulations in Germany for agency approval requirements.  You still need to get the tubes from another source or use your existing tubes from an older clock that you want to update.  PV Electronics has convenient support for DST.  Both have GPS support.  The PV menus are easier to follow, IMHO, and the features are more robust.  The Blue Dream from Nocrotec has a more pleasing colon fade on/off.  If you are looking for a wide variety of tube options or to use larger tubes like the 568, I would definitely look to PV Electronics.  Pete from PV will absolutely take care of you.  If you have the budget to purchase some beautiful tubes, PV Electronics has a kit that supports the Dalibor Farny 568 tubes, which are a work of art!

 

http://www.pvelectronics.co.uk

http://www.nocrotec.com

http://www.daliborfarny.com/r-z568m-nixie-tube/

 

 

If I have slighted another good supplier – apologies.  I have product(s) and good experience with these sources and would recommend them for quality and support.  There are a lot of other sources if you are looking for smaller clocks.

 

Jeff

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[Niek]

I'm not sure I'd recommend the pvelectronics clocks. I know they seem to be quite popular, but they appear to be using the HV5622 out of spec. It's strange to see so many nixie clock designs use these chips out of spec, when there are many other options to do this correctly.

Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/HV5622%20C072313.pdf

PV Electronics schematic: http://www.pvelectronics.co.uk/kits/spectrum/spectrum_V5.pdf

As you can see in the datasheet, under recommended operating conditions:

VDD Logic voltage supply MIN: 10.8V, MAX: 13.2V

And in the schematic VDD is shown with 5.2V. There's no good reason to use chips out of spec (they didn't put that MIN 10.8 there for nothing), and it makes the design potentially unreliable. I'm sure it works for many, but that's no guarantee that it won't fail at some point. Or that if you need to replace them one day, and they're using a different process to manufacture these chips, they no longer work at 5V. It's simply poor practice, and unnecessary given the alternatives.

[Jeff Walton]

It would be nice if the HV5622 manufacturer would provide guidance for 5V operation in addition to 12v, but I suppose that is not their target market. With CMOS chip design it is likely a speed / noise / timing issue more than anything else and there are many designs that successfully use these parts at TTL logic levels and lower clock rates. The internal technology is certainly capable of operation at 5V with good waveforms and the timing is not tight. It would be surprising if anyone is attempting to "select" chips for their products and more likely that the timing data just needs to be restated. The manufacturer is going to always try to yield and test at the high end of the spec because that is the competitive nature of "specsmanship".

In the absence of other guidance from the manufacturer, it is technically correct that the chip is being used out of spec and a major chip or process design change could cause problems for parts replacement in the future. Practical use of this current chip design in an application with low clock speeds at TTL logic levels is not a device reliability concern but it does potentially make the design more susceptible to unknown timing issues. Multiple supply voltages and level shifting may be proper and do add more of complexity to designs but I think that a nixie clock will likely fail from other causes than this.

Interesting topic! I spent a number of years working with implantable medical electronics customers and if you ever want to get into some real spec and reliability discussions (and legal..), it makes our issues seem trivial.

Jeff

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[David Forbes]

One could take the NASA approach, wherein they thoroughly characterize
every component they buy for use in their outer-space conditions, since
the manufacturer does not do so.

They also have to redo this exercise if the part design or manufacturing
process is changed at all.

On 5/19/16 8:38 AM, Jeff Walton wrote:
> It would be nice if the HV5622 manufacturer would provide guidance for 5V operation in addition to 12v, but I suppose that is not their target market. With CMOS chip design it is likely a speed / noise / timing issue more than anything else and there are many designs that successfully use these parts at TTL logic levels and lower clock rates. The internal technology is certainly capable of operation at 5V with good waveforms and the timing is not tight. It would be surprising if anyone is attempting to "select" chips for their products and more likely that the timing data just needs to be restated. The manufacturer is going to always try to yield and test at the high end of the spec because that is the competitive nature of "specsmanship".
>

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David Forbes, Tucson AZ

[SWISSNIXIE - Jonathan F.]

Its not too hard to make it to 12V use, i always used the 4504 Hex Level shifter for logic level translation. Price about 1$. I also have a solution when 12V is not available in the circuit. The ST66 family is a 8-soic chip that can deliver 11-12V @30mA from 5V. Very nice and small part. I used it for my latest project which can be driven by 7-18V.