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MM5314N clock chip - VFD tubes

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DT98

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I've been searching for information for a vfd clock using individual tubes. I have a scad of IV-11 tubes and would love to build a clock.

I seems the problem is with the required power supplies, etc...most posts I find are three or four years old. I get the feeling interest is failing for vfd tube clocks because the price of these tubes is very low on ebay.

Does anyone have a schematic, etc...that I could beg borrow or steal??...better yet if it includes the necessary programmed PIC.

I'm 53 and studied two years EE in college before leaving for a career in telecom and I really don't want to learn PIC programming, compilation, burning the chips, etc...but I do love constructing and the building and assembly of the clocks.

Does anyone have any thoughts on how to take a MM5314 clock chip which has 7 segment output and drive/convert for vfd tubes?

I would also love to take one of my favorite nixie clock kits that uses a PIC processor and has BCD output and use it to drive the vfd tubes but have no idea how to do it.

I have a few basic clock kits that use the mm5314N clock chip and six individual 7 seg red led displays. The 7 seg led itself is 14mm tall. I have one or two of these and tried to convert to numitron tubes but the clocks are still not what I want them to be but they work...

Anyone interested in trading vfd info/schematic for 5314 clock chip led kit??

Regardless, I enjoy reading the posts and wish I had stayed with EE 30+ years ago instead of going into telecom...hind sight is perfect

Thanks for reading,
DWT98
 
Hi,

I have never used VFD/glassware before, despite my obsession with everything that 'glows' :)

As far as I can see you're only problem is the driver side of things, as you already have a way of turning segments on/off for a clock. You'll need something that can cope with >30V with multiple outputs.

Some links:
http://www.tube-tester.com/sites/nixie/different/bl-100/sylv.htm
http://www.turbokeu.com/myprojects/vfdclock/iw-18 dcf clock.gif (great site that)

**broken link removed**
**broken link removed**


Unfortunately, most of these drivers are serially controlled...whereas your MM5314 is a true 7-seg driver. So either you shoudl search for specialist chips (of which there are quite a few) which will translate the voltage levels....or, build a discrete version with HV transistors?

I'm sure driving these tubes is more complicated than simply 'using a high voltage', with blanking etc.. but its been done before, and google privided lots of links.

I'm sure the folks at the bit-tech forum would help you out ;)

Blueteeth

Another link:
**broken link removed**
 
Last edited:
I've been searching for information for a vfd clock using individual tubes. I have a scad of IV-11 tubes and would love to build a clock.

I seems the problem is with the required power supplies, etc...most posts I find are three or four years old. I get the feeling interest is failing for vfd tube clocks because the price of these tubes is very low on ebay.

Does anyone have a schematic, etc...that I could beg borrow or steal??...better yet if it includes the necessary programmed PIC.

I'm 53 and studied two years EE in college before leaving for a career in telecom and I really don't want to learn PIC programming, compilation, burning the chips, etc...but I do love constructing and the building and assembly of the clocks.

Does anyone have any thoughts on how to take a MM5314 clock chip which has 7 segment output and drive/convert for vfd tubes?

I would also love to take one of my favorite nixie clock kits that uses a PIC processor and has BCD output and use it to drive the vfd tubes but have no idea how to do it.

I have a few basic clock kits that use the mm5314N clock chip and six individual 7 seg red led displays. The 7 seg led itself is 14mm tall. I have one or two of these and tried to convert to numitron tubes but the clocks are still not what I want them to be but they work...

Anyone interested in trading vfd info/schematic for 5314 clock chip led kit??

Regardless, I enjoy reading the posts and wish I had stayed with EE 30+ years ago instead of going into telecom...hind sight is perfect

Thanks for reading,
DWT98
I am looking at a schematic of a MM5314 clock that I built in 1996 and it is driving a Futaba 5LT43 vacuum flourescent display. This display is multiplexed. My notes show the segment drive of the 5314 being a positive gate, and segment A thru G going directly to the segments of the display.
My notes also show the digit drive, M1,M10,H1,H10,S1,and S10 being a negative going gate. I used a ULN2004 to invert the digit drive. The output of each of the 2004 invertors has a 1.5K pull-up resistor to Vcc. The inputs of the 2004 go directly to the digit drive. F1 of the VFD goes to ground and F2 has 2 ea 250 5W resistors in parallel from it to Vcc. Vcc is approximately 12VDC.
Hope this helps
Ned
 
Hello Ned,

Did your Futaba VFD display require a grid voltage, etc... that is required for individual vfd tubes?
I gotta ask, would you share your schematic? This might let me see if I can put a clock together using individual vfd tubes on the MM5314N chip.
In the long run I am hoping to find a schematic that will work with six vfd tubes and a pic processor. I'm trying to talk a buddy of mine that programs to see if he wants to learn all about pics...we'll see.
Thanks again...
Dennis
 
Blueteeth,
Thanks for the info. I've googled but not had a lot of success but I'll keep looking. I've seen a lot of posts from turbokeu...some are posts from 2003,4,5,etc...as much as I like lights I guess it's a good thing I have none of his knowledge...
Like I said, I can assemble and build from a schematic but I don't have the $$$ to experiment...
Everytime I let the smoke out of the devices, they quit working for some reason and I can't get the smoke back in... SFT smoke filled technology, when you let the smoke out, it's too late :)
I'm still looking up the links you provided.
Thanks!
DT89
 
Hello again Blueteeth,

I've looked again at a couple of the links...

Tubetester...awesome clocks. I have three of their clocks..two numitron tube clocks and one biquanry (sp) nixie clock. I don't really care for the Dallas RTC chip that houses the freq crystal...two of the clocks drift quite a bit and they told me there were problems with the earlier Dallas chips and there's not much that can be done...
The clock in the schematic is a type of vfd clock. There is one for sale on ebay now. But these Sylvania tubes do not use a grid so the schematic is not what I am looking for but tubetester does some great work. The clear Sylvania tubes are soo cool looking and if I had the extra bucks I'd get it...but the financial markets here are not looking too great right now.

The schematic turbokeu is using for the IV-18 tube I think it is looks slick. He is using an AC voltage for the heater. I've read using an ac voltage elilminates the problem of using a dc voltage which causes some of the digits to display at varying intensity due to voltage drop off.

The only issue is these use PIC processors and while they are available, I know better than to ask someone for their code...free or otherwise. It would be like asking for free software... :)

I'm still looking...thanks again,
DT98
 
hi again,

Yeah, I thought the PIC processors would be an issue...as with all things 'programmable', if you are into them, then you end up using them for most projects..but if you're not, then its not always worth the hassle of learning code/programming/quirks of the chips just for a one-off device. Always handy of you know someone who can help with it, bribe them with kind or threaten to break their legs :)

I've been going over those serial driver chips used by turboku..are the tubes he's using the closest to the ones you have? in terms of driving signals/voltage/grid etc..??

If they are (big 'if' I know) then we can use schematics for driving those as a reference, and attempt to design a circuit that behaves the same way as those serial driver chips, but with a parallel interface...without special (read: expensive) IC's...using only whats widely available.

Because ultimately, the PIC's used, send the drivers the same info as a MM5314, just in serial format, and they add 'blanking'. All they are really are serial to parallel converters, with an output enable (blanking) and high voltage capability. Depending on the drive voltage you need, you might be able to use a UN2003A darlington driver or something (50v capability, medium current), along with a TTL octal buffer (74HC541, or 74HC540 for inverting outputs). Blanking can be done with the 'output enable' of the buffer.

Getting a blanking signal from your clock chip could be tricky..it doesn't have one. However, according to the datasheet for the A6812SA (used by turboku) all it does is pull all outputs low. I'm afraid I don't know enough about your tubes to know what the exact timing requirements are. I still think it could be done with a little logic, or even transistors.

As for power supplies... even with the financial markets as they are, DC-to-DC circuits are easy :D Anything from specialist IC switched mode boost converters, down to a 555 timer with an inductor, or voltage multiplier. Interesting idea about using AC for the filament heater.

It woudl be quite cool if you did it yourself from 'scratch', always satisfying creating something that doesn't currently exist.

Blueteeth
 
Hello Ned,

Did your Futaba VFD display require a grid voltage, etc... that is required for individual vfd tubes?
I gotta ask, would you share your schematic? This might let me see if I can put a clock together using individual vfd tubes on the MM5314N chip.
In the long run I am hoping to find a schematic that will work with six vfd tubes and a pic processor. I'm trying to talk a buddy of mine that programs to see if he wants to learn all about pics...we'll see.
Thanks again...
Dennis
Dennis,
I don't have a scanner so do post a schematic I would have to regenerate it.
But to answer your question yes the VFD had grids. The segment drive is the grid connection. As I recall if the grids are at ground that digit is off. Since the grid driver is an invertor (uln2004) the grids are at ground. When a negative gate is on the input to the invertor the output goes high and turns that digit on. Course the digit drive and the segment drive are multiplexed.
Ned
 
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