Nixie Power Supply not working.

[MetalUpYerEye]

I built a Nixie power supply for a tube project and its not getting any output voltage. I get like .85 volts to ground on the output with a 12v source. I used this layout... http://dl.dropbox.com/u/967492/555%20SMPS.gif

I'm not sure if I have the right inductor though. I used a 100uh inductor from Tayda Electronics and I remember someone saying they used one from another place. All the connections seem to be good and I double-checked the layout with the schematic for the power supply.

Any ideas besides the inductor?

[iccaros]

are your transistors in the right way, I remember people having issues with the direction of the drawing. Check the datasheet and ensure the pins are were they should be, from the schematic.

[MetalUpYerEye]

I just checked everything... The BS547 was backwards but turning it around yields the same results... Luckily now its oriented properly and thats one less thing to worry about... But we're still back where I started...

[iccaros]

do you have another, I remember a thread in the superfly that stated they burned one out having it the wrong direction.  I use a 100uh in mine, so the inductor should not be the issue. but torodial inductors are bad for this, so as long as it is not that type it should be fine.

do you have some measurements of the 555 output?

also which type of 555 are you using, there is some talk again in the superfly thread about maybe the mosfet version not working in this design.

[frequencycentral]

You used this inductor? http://www.taydaelectronics.com/servlet/the-40/100uH-Inductor/Detail

I use this inductor: http://www.rapidonline.com/sku.aspx?tier1=Electronic+Components&tier2=Inductors+And+Chokes&tier3=Leaded+Inductors&tier4=Low+current+radial+lead+inductors&moduleno64730&catref=88-1630

I'm not convinced those that you used will work in this circuit.

[iccaros]

I used this on http://www.mouser.com/Search/ProductDetail.aspx?R=RLH0912-101KBRLvirtualkey65210000virtualkey652-RLH0912-101KBRL

Its the same as Ricks, Just can handle more amperage so its a little bigger than the pictures I a have seen of his builds, but fits the layout no problem.

[MetalUpYerEye]

Rick, thats the inductor I used from Tayda. It must be the problem. I'm not sure which type of 555 I have in there off the top of my head but everything else is the same as the layout.

[MetalUpYerEye]

I sorted this out. For anyone wondering, the inductor from Tayda was the issue. I'm not sure the exacts of it but obviously its a different kind of inductor and wasn't functioning properly for the intended purpose.

I salvaged a couple inductors that looked similar to the one FC posted in his Superfly builds on an old power supply I had sitting around the garage. I happened to have a schematic for that particular supply which identified them as 300uh inductors. I remembered reading somewhere that Nixie power supplies should work with 100uh-450uh inductors so I gave it a shot and now it seems to be working properly. I have 150-280 volts available via the trim pot.

Weren't you guys getting 150-200 volts though?

[frequencycentral]

It'll drop under load. You can also tweak the possible voltage range by dinking with the resistor values either side of the trimmer. But be cautious - insane capacitor-melting voltages are possible. On one Superfly I built I panel mounted a 500R pot to act as a power break.

[MetalUpYerEye]

I'm not gonna mess with the resistors. 200 volts should be plenty since I think the 6021 is rated for like 160 volts... 

I need to get an output xfmr now... So I can build up the tube side of the circuit and start tweaking sounds... Unless there's a way to hear it without the xfmr, 

How much current is this particular circuit rated for? I'm using a 1 amp wall wart.

[Perrow]

I'm not sure where you are, but for Europe I think Musikding has the cheapest output xfmrs.

Just for the record, I got mine working now with Futurlecs 100 uh power inductor (PIND100), and a new 555. Boy did I try a lot of things before subbing the 555.

Edit: and I used a 5089 instead of the 547.

[MetalUpYerEye]

I used all the same parts as the layout with the exception of the 300uh inductor that I salvaged and the large output cap. I used the value that FC has in his Superfly Special layout rather than the one on the Nixie layout.

I was gonna get my output xfmr from Antique Electronic Supply. They have a Hammond Fender replacement xfmr for $16.30. Primary 22,800 ohms, secondary 8 ohms, 3.5w audio power. But no center tap...? Here's the link...

http://www.tubesandmore.com/scripts/foxweb.dll/moreinfo@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?item=P-T1750A

[frequencycentral]

That's a singled ended transformer. You want a Hammond 125A push/pull or similar for Superfly. I highly recommend Bluebell Audio in Scotland: http://www.bluebellaudio.com/transpushpullop.htm

[MetalUpYerEye]

I need a source in the US...

Antique Electronic Supply has them but they're $36... 

[iccaros]

http://www.musicalpowersupplies.com/

you want the OT5PP

I have bought four transformer from him, Shipping is $8

Fast, and good quality. The Hammond has more taps, While this one is made for the Firefly type amp.

[MetalUpYerEye]

Thanks! Thats perfect. It's $35 shipped but it also has outputs for different impedances of speakers. 

[iccaros]

While I like Antique Electronic Supply, they charged me almost $15 to ship a transformer, if you are buying a lot of things, the rate does not change much, as caps and resistors and even tubes don't weigh much.. But if you just need the transformer, MPS is good deal, Plus for  small fee he is willing to talk about designing a supply for you, in case you need something odd.