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1  Projects / ArduiNIX / Re: Excess MOSFET Heat and Voltage Bleed on: March 18, 2014, 12:41:55 PM
It seems to be only the first two tubes that are ghosting which are connected to the same cathode/shift register. I did some debugging where i disconnected various cathode pins to determine if there was a short but that was uneventful.  I'll do some more testing and get back to you.
2  Projects / ArduiNIX / Re: Excess MOSFET Heat and Voltage Bleed on: March 17, 2014, 06:06:21 PM
Apparently the ghosting has nothing to do with sharing an anode. I finally finished my software and when i display 5:00PM there is a ghost in the first hour digit (which is disabled):


Based on other post's i've seen the shift registers are probably the cause.
3  Projects / ArduiNIX / Re: Excess MOSFET Heat and Voltage Bleed on: March 17, 2014, 11:41:18 AM
Here's a picture of the ghosting i was talking about. This happens when i'm only illuminating the neon tubes (the cathodes for the nixie tube are all OFF/LOW state... shift register is 1/1/1/1):


Here's a picture with all the nixie + neon tubes illuminated with a 1ms delay. There's no ghosting but the MOSFET is too hot (laser temp is 140F). This is bound to cause the neighboring ceramic caps to fail.
4  Projects / ArduiNIX / Re: Excess MOSFET Heat and Voltage Bleed on: March 15, 2014, 02:39:07 PM
Hello,
     I'm building clock with four IN-4 and INS-1 Neon Tube colons. I have everything wired but i'm having some issues with the MOSFET heating up and an issue where voltage is leaking to cathodes. For example, anode2 is shared by a nixie tube (cathode1) and the INS-1 colon (cathode1). When i fire the colon, some voltage is bleeding through to the nixie tube.

    I'm wondering if i damaged the SN74141's. I didnt' have any sockets on hand and impatiently solder'd them directly.

    FYI, here's a link to my Driver software. Still a work in progress. If the C++ pattern ends up being too slow i'll re-write it in C-style code:
https://github.com/waldo1979/WitchingHour

-Waldo

Can you tell me a bit about your setup?

Do the tube and colon share a common anode as well?
Are they both resistored on the anode?

Try different anode channel per unit. And use the multiplexing to gate them.

Below is a table describing my tube wiring. The nixies have a 10k resistor on the anodes and the neons are connected in series with a 47k resistor. When I illuminate the neon tubes (colon) and leave it on the Nixie->hour2 has a ghost. Using a different anodes have the same effect. if i illuminate in a loop with a delay the ghosting isnt visible.

The wiring to the tubes is AWG 28 (http://amzn.com/B007R9SQQM), which might be a little small. The tubes are socketed using sockets from Germany i bought off ebay: http://www.ebay.com/itm/331114980365

When the neon tube is illuminated, if i take a voltage reading from the cathode pins which are supposed to be in the off/low state and ground there is 140~ volts. I checked for shorts but didn't see any. Seems like the problem lies within the shift registers.

Anode1Nixie->Hour1
Anode2Nixie->Hour2, Neon Tubes
Anode3Nixie->minute1
Anode4Nixie->minute2
Cathode0Nixie->hour1, Nixie->hour2
Cathode1Nixie->Minute1, Nixie->Minute2, Neon Tubes

5  Projects / ArduiNIX / Excess MOSFET Heat and Voltage Bleed on: March 15, 2014, 04:28:44 AM
Hello,
     I'm building clock with four IN-4 and INS-1 Neon Tube colons. I have everything wired but i'm having some issues with the MOSFET heating up and an issue where voltage is leaking to cathodes. For example, anode2 is shared by a nixie tube (cathode1) and the INS-1 colon (cathode1). When i fire the colon, some voltage is bleeding through to the nixie tube.

    I'm wondering if i damaged the SN74141's. I didnt' have any sockets on hand and impatiently solder'd them directly.

    FYI, here's a link to my Driver software. Still a work in progress. If the C++ pattern ends up being too slow i'll re-write it in C-style code:
https://github.com/waldo1979/WitchingHour

-Waldo
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