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8/7/2015 Variable Dekatron Spinner Kit | Threeneuron's Pile o'Poo https://threeneurons.wordpress.com/dekatronstuff/variabledekatronspinnerkit/ 1/8 Variable Dekatron Spinner Kit Thank you for your purchase of this dekatron spinner kit. Available on eBay , as either a bare printed circuit board (PCB), or with all requisite parts, less the dekatron, along with the PCB. As opposed to most dekatron spinner circuits, online, this unit is powered from a low voltage source. 12V nominally, and draws ~120mA of current. The circuit, itself, “pumps up” the voltage to the required 450V, that these tubes need. Update June 2015: Revision B, but using Revision A Board. A few value changes. The prior values still work. Newer values increase voltage, and put less stress on the components. Update September 2012: Jumpering info added to support OG8 & OG9 dekatrons. OG9 jumpering corrected Oct 15, 2012. Note: Dekatron is not sold with kit. You need to acquire that separately. If this circuit “bites” you, usually its does little, or no harm. However, some care must be taken to avoid getting shocked by this circuit, especially for those with heart conditions. Avoid touching any of the traces when the circuit is ON. That said, its much safer than other circuits powered directly from the high voltage AC lines. Following, are the guidelines, for you to build your kit (click photo below, to view video): The schematic (click to enlarge): Threeneuron's Pile o'Poo of Obsolete Crap Home Links Nixie Stuff Dekatron Stuff Magic Eye Stuff VFD Stuff Miscellaneous Projects
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8/7/2015 Variable Dekatron Spinner Kit | Threeneuron's Pile o'Poo
https://threeneurons.wordpress.com/dekatronstuff/variabledekatronspinnerkit/ 1/8
Variable Dekatron Spinner KitThank you for your purchase of this dekatron spinner kit. Available on eBay, as either a bare printed circuit board (PCB), orwith all requisite parts, less the dekatron, along with the PCB. As opposed to most dekatron spinner circuits, online, this unitis powered from a low voltage source. 12V nominally, and draws ~120mA of current. The circuit, itself, “pumps up” thevoltage to the required 450V, that these tubes need.
Update June 2015: Revision B, but using Revision A Board. A few value changes. The prior values still work. Newer valuesincrease voltage, and put less stress on the components.
Update September 2012: Jumpering info added to support OG8 & OG9 dekatrons. OG9 jumpering corrected Oct 15,2012.
Note: Dekatron is not sold with kit. You need to acquire that separately.
If this circuit “bites” you, usually its does little, or no harm. However, some care must be taken to avoid getting shocked bythis circuit, especially for those with heart conditions. Avoid touching any of the traces when the circuit is ON. That said, itsmuch safer than other circuits powered directly from the high voltage AC lines.
Following, are the guidelines, for you to build your kit (click photo below, to view video):
The schematic (click to enlarge):
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Both older and newer values (in red) can be used. Newer values shipped with kits solder after June 9, 2015.
This circuit can be divided into two sections: (1) the switchmode HiV power supply, and (2) the relaxosc spinner.
In the “nixie realm” switching supplies have been based on one of the three following chips: the MAX1771, the MC34063, orthe NE555. If you look at the board, you’ll see that the chip is way too far from the power FET, so it can’t be the MAX1771,since it would not be stabile, with this lessthanideal layout. Its not using a MC34063 either. Maybe, a cheap 555. Nope, evencheaper, a LM393 dual comparator. This chip sells for less than the 555, but don’t let that fool you. In this app, its actuallysuperior to the 555. 555’s usually use a trimpot to adjust the voltage. They don’t possess an internal voltage reference like theMAX1771 and MC34063. If you use an external reference (zener diode) with the 555, you need a voltage comparator, too.Most hobbyist use a common opamp for this purpose. It does work, but not only is it not ideal and it adds an additional chip.Here the chip IS a voltage comparator, so one stage is used to compare the reference (D4) to the output, while the other stageis used to make a squarewave generator. That squarewave pulses the switch FET, which in turn generates highvoltage pulses,by switching current thru the inductor (L1). Also, the turnOFF of the FET is the more important transition, than the turnON. The LM393 has open collector outputs. Turn ON is slow, thru R6, but turnOFF is quick, thru its open collector stage, toGND. This is opposite than the MC34063, which has active pullup (ON), but passive pulldown (OFF). With the MC34063, anactive pulldown stage must be added (MK1.5). This supply has plenty of power to drive that one dekatron, and several more.
To make the required 450V, the supply switches 225V, and uses a doubler, to make the 450V. The 225V can be tapped to drivesmall nixie clocks, if less than 15mA is all that’s required.
The relax oscillator section, makes up only a small portion of the circuitry. It uses a simple neon relaxation oscillator (R13, C5,NE2) to make the cadence pulses. These pulses pass thru the baseemitter leg of Q2, thru R14. R14 moderates the currentgoing thru Q2. In doing so, the time needed to discharge C5 increases. Q2 pulses the dekatron’s guides. G1 directly, and G2,delay thru R17 & C6. R14 may need adjusting, in order for the pulses to be wide enough to step the dekatron. If made toolarge, R14 will take too long to discharge, and the oscillator will stall. The dekatron’s cathodes (K, NDX) are biased to roughly+60V. That way, the pulses at G1 & G2, which transition from ~+120V to 0V, look like +60V to 60V, as the dekatron seesthem. A negative voltage on the guides (G1 & G2) is needed (relative to the cathodes), for proper stepping.
The parts list (click to enlarge):
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For the most part, component selection is not too critical. They largely need to just fit on the board, in their assignedlocations. All of the resistors are common 1/4W 5% carbon film resistors. These resistors also have high enough voltageratings needed in this circuit. The most critical parts are the Coil (L1), power FET (Q1), and ultra fast recovery rectifiers (D1D3). Don’t skimp on these parts. The coil should be rated for peak currents of at least 0.5amp. The FET should be rated for atleast 250V, and an ON resistance, no more than 3 ohms. Use rectifiers with switching speeds of at least 100nS. Your common1N4004, has switching speed is many times slower than that, and is not usually given in datasheets. It has also been shownthat many Chinese (Hong Kong included) vendors just restamp parts, so buy from large stocking distributor, wheneverpossible.
Note: If you bought this as a kit (with the parts), you will receive either D4A or D4B, and either Q1A orQ1B. You only want to install one type of part in these locations. If you install D4A, DO NOT install D4B,or the other way around. If you install Q1A, DO NOT install Q1B, or the other way around. The ‘A’ and ‘B’locations are provided as a convenience, allow different component ‘packages’ to be used. Not everycomponent location needs to be occupied.
As of late December 2012, D4B (BZX55B2V4) zener diodes are being shipped, replacing D4A (LM385), inthe kits. These are glass diodes (DO35 package), and look the same as D1 thru D3 (BAV21 rectifiers).Note the BAV21’s have “21” printed on them, and come in a set of 3 ! Please do not mix them up !
UF4007 can also come with kits for D1 thru D3. They use a DO41 package, which is the same as the1N400X (D5). Again do NOT mix them up !
Contact me, if you are missing components that DO NOT have the ‘A’ or ‘B’ suffix.
If you’re still kinda new on this whole electronics thing, here is a sheet to help you ID parts (click to enlarge):
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Template of the PCB, for locating critical parts, and the intended orientation (click to enlarge):
If you just wire up your kit, the octal socket (P1) will be prewired to accommodate the Russian OG4 dekatron. This is themost commonly available octal base dekatron at this particular time (end of 2011). It can be rewired for other types of octalbase dekatrons. The 6802 and GC10B (& GC10/4B) are the most common Western types, and the rewiring for those isshown, in several places.
The biggest difference from the original version, is the spacing between J2 and J3. They are now 0.3″ apart, which means a 16pin DIP socket can be inserted, allowing for the use of “headers”. Below is the board with the socket installed. A secondsocket can be wire for the dekatron type desired. (Click to enlarge):
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DIP IC sockets can be stacked on top of each other, allowing for a quick makeshift header. Screw machine sockets work bestfor this task. Below shows the header plugged in. (Click to enlarge):
Several headers can be made, so the one kit can accommodate several tube types, simply by changing the header. Also, notethat several models use a smaller anode resistor (R10). To accommodate this, the R10 slot, can have the smallest resistorvalue inserted, which is 150K for the OG3. The additional resistance can be made up, by adding a resistor on the headers. Fora 6802, or GC10B, the total R is 560K. Less 150K, is 410K. A 390K is close enough, so solder it between pin 3 and pin 13 (pin4 of J3) of the ‘6802’ header. For a DK23, 390K less 150K is 240K. A 220K will do, and goes between pin3 and pin9 (pin 8 ofJ3), of the DK23 header.
Below, are examples of rewiring options for the older version which can still be used as shown. (Click to enlarge):
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Here are J2J3 jumper arrangements for other tube types(click to enlarge) :
Once your kit is done (less dekatron, J2 & J3, which are NOT included), it should look something like this (click to enlarge):
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Now find yourself a 9VAC, or 12VDC (200mA) wallcube transformer (aka adapter), with a 5.5mm OD x 2.5mm ID power plug,and of course that dekatron tube, and you’re good to go.
Below is for OLDER version ONLY ! – BEFORE MAY
2012:
Below is the placement of the original kit, in case you bought yours before May 2012. (click to enlarge):
Enjoy your Kit, and thanx again.
End.
