Re: [neonixie-l] Re: Help required on nixie power supply

Gad to see you got it running. Be sure to stress it over a wide range of supply voltages & load-currents to ensure it's robust. I also recommend probing around with a scope to make sure other signals are clean. There are some good PCB-layout tips on the web for reducing noise. Many of them are

Re: [neonixie-l] Re: Help required on nixie power supply

Just an update. A 100pF cap over the resistor has indeed fixed the issue. > Noise on the FB pin is a common problem with poor layout, hence asking for > a look at it. > I thought my layout would be ok. Maybe I'll remove the ground-plane keepout under the inductor next time as I'm using a

Re: [neonixie-l] Re: Help required on nixie power supply

Noise on the FB pin is a common problem with poor layout, hence asking for a look at it. You should not need any other bypass caps if the layout is good and the component choice likewise. Nick On 15 July 2016 22:01:39 BST, gregebert wrote: >Although the supply is

[neonixie-l] Re: Help required on nixie power supply

Although the supply is behaving like it's under-loaded, there could be another culprit: noise. I've looked at the schematic, and it's possible that the PCB layout could be injecting excess noise into the MAX1771. Is the bypass cap C3 located as close to the 1771 as possible ? I think C4

[neonixie-l] Re: Help required on nixie power supply

Also here is an attachment showing what the entire assembly looks like at the moment. The two boards on the back are for power and control, and are not finished yet as I'm still testing/assembling. -- You received this message because you are subscribed to the Google Groups "neonixie-l"

[neonixie-l] Re: Help required on nixie power supply

Can you post a schematic ? I'm a bit concerned about the 250V-rated MOSFET, when you mentioned ~300V was measured. Is the MOSFET exposed to this voltage, or is there a doubler/tripler ? My first guess is the supply is *under*-loaded, because the feedback mechanism is basically doing it job.

[neonixie-l] Re: Help required on nixie power supply

I would try something between 10 and 200pf (0.01 and 0.2 nf). Anything more will maybe cause another problem. About the output cap, check its ESR, it will affect the overall performance. Also check if all solder-joints are in good quality. -- You received this message because you are

[neonixie-l] Re: Help required on nixie power supply

Oops I meant 0.1nF for the capacitor across the 1.5M resistor, although I'm assuming 0.1uF would still be ok? -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to

[neonixie-l] Re: Help required on nixie power supply

It seems like that is the issue. I can't find a suitable capacitor at the moment as the 0.1uF ones I have extra right now are rated at 50V, but using my multimeter to probe across the 1.5M cap causes enough parasitic capacitance to allow for a stable voltage output. I will order a similarly