Help with Nixichron Issue

David Fleig

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Jun 2, 2019, 4:44:05 PM6/2/19

to neonixie-l

Hello,

I've got a Nixichron purchased from Jeff Thomas years ago that's not behaving. It starts up and runs fine for several hours or even a few days then starts emitting a continuous beep and the display goes blank. Unfortunately, it's random enough that no ones seen it actually happen, we just hear it. Unplugging it and plugging it back in fixes the problem until it happens again. Jeff had fixed this issue a couple times for me but I never got the details on what he did. I've looked over the board and don't see anything obviously wrong. I've also pulled the processor and level-shifters out, cleaned the terminals and replaced them but it hasn't helped.

Does anyone have any suggestions for my beloved Nixichron?

Thanks,

David

David Fleig

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Jun 2, 2019, 4:55:09 PM6/2/19

to neonixie-l

I forgot to mention that the GPS received isn't in an optimal position so it doesn't always have a signal.

David

Terry Kennedy

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Jun 2, 2019, 6:09:23 PM6/2/19

to neonixie-l

On Sunday, June 2, 2019 at 4:44:05 PM UTC-4, David Fleig wrote:

I've got a Nixichron purchased from Jeff Thomas years ago that's not behaving. It starts up and runs fine for several hours or even a few days then starts emitting a continuous beep and the display goes blank. Unfortunately, it's random enough that no ones seen it actually happen, we just hear it. Unplugging it and plugging it back in fixes the problem until it happens again. Jeff had fixed this issue a couple times for me but I never got the details on what he did. I've looked over the board and don't see anything obviously wrong. I've also pulled the processor and level-shifters out, cleaned the terminals and replaced them but it hasn't helped.

I have one that used to do that a lot. Updating to the latest firmware (from MichaelB) helped somewhat, but putting it on a UPS seems to have solved the issue. Based on that, I suspect that some power glitches are latching up the power-on reset logic in the clock. Fitting a large-value capacitor across the power input may help (you can test this on a disposable power adapter, rather than opening the clock up again).

MichaelB

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Jun 8, 2019, 1:20:17 AM6/8/19

to neonixie-l

What GPS are you using? The original HaiCom 204III? Believe it or not I have had one of mine do that very same thing and the issue was a bad HaiCom. Try changing to a BR355 or another Haicom. I have a boatload of them I am more than willing to part with for a song., The other cause for that phenomena is static discharge. Does your unit have the grounding 'spring' I'll call it, added that grounds the PCB to the chassis? And if it has it, does it in fact make contact with the case. They can become bent so they are non-functional with a lot use. If it doesn't have one you can easily fab a makeshift case ground of some sort.

David Fleig

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Jun 10, 2019, 11:36:35 AM6/10/19

to neonixie-l

I switched to a different power supply and it's been running fine so far. If it happens again I'll try the cap.

Thanks,

David

nixiefanvinh

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Dec 1, 2019, 3:11:02 AM12/1/19

to neonixie-l

Mine was doing this too! And it was getting quite annoying, as sometimes it would happen in the middle of the night. It's stopped doing this, but has another problem now... It always thinks it's April 15, 2000... 04 15 00

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