FAQ
TL;DR: PNW-57/NS-71 image-intensifier tubes need 14 – 19 kV DC yet draw only ≈10 µA [Elektroda, krakowmichal, post #12953220]; “these tubes consume … microamperes” [Elektroda, Krzysztof Kamienski, #18862513]. Below is a vetted parts-list and troubleshooting FAQ for DIYers repairing or miniaturising Soviet night-vision HV converters.
Why it matters: The right 15 kV supply keeps the optics sharp and prevents costly tube burn-out.
Quick Facts
• Operating voltage: 14 – 19 kV DC per tube [Elektroda, krakowmichal, post #12953220]
• Load current: 0 – 15 µA (“microamps”) [Elektroda, Krzysztof Kamienski, #18862513]
• CCFL inverter output: 3 – 4 kV AC @ ≈60 kHz; add 3-stage doubler to reach spec; matchbox size [Elektroda, Krzysztof Kamienski, #17963257]
• DIY USB-plasma-ball converter parts cost ≈ PLN 20–40 / USD 5–10 [Elektroda, krakowmichal, post #14970418]
• Over-voltage blurs focus and can puncture photocathode—keep within spec [Elektroda, Krzysztof Kamienski, #18025015; Elektroda, AlekZ, #18030177]
What high voltage do PNW-57 and NS-71 image-intensifier tubes actually need?
Both use WEI-1 class tubes that start at 14 kV and work up to about 19 kV DC. Below 14 kV brightness drops; above 19 kV risk of puncture rises [Elektroda, krakowmichal, #12953220; Elektroda, AlekZ, #18862501].
How much current do these tubes draw?
The photocathode needs only dark current plus signal—typically 2 – 15 µA. “These tubes consume … microamperes” [Elektroda, Krzysztof Kamienski, #18862513]. A 15 µA limit means <0.3 W even at 19 kV, so AA cells or 9 V blocks suffice.
Can I power the goggles with a cheap CCFL inverter module?
Yes. A CCFL board gives 3 – 4 kV AC at 60 kHz. Add a 3-stage Villard doubler (6 × 27 pF 3 kV caps + 6 × 5 kV diodes) to reach ≈12 kV DC; a fourth stage pushes it into the 15 kV window. The finished unit fits a matchbox once potted in paraffin [Elektroda, Krzysztof Kamienski, #17963257].
How do I build the PLN-20 plasma-ball converter everyone mentions?
- Salvage the USB plasma-ball driver; its secondary gives ≈5 kV from 5 V input.
- Feed that node into a 4-stage capacitor-diode multiplier using 27 pF / 3 kV SMD caps and 5 kV DO-15 diodes [Elektroda, krakowmichal, #14970418; #15045979].
- Run the board on 3 V (2 × AA) to land at 14 – 18 kV. Space parts >6 mm or arc-over occurs [Elektroda, krakowmichal, post #15028993]
One eyepiece is brighter than the other—can I equalise it?
You cannot trim gain electrically; each tube’s photocathode ages differently. Swapping tubes left-to-right confirms the culprit. Replace the dim tube or live with the mismatch; lowering supply voltage darkens both [Elektroda, Dolby*, #3436157].
What happens if I exceed the rated voltage?
Focus shifts because the internal electrostatic lens shortens; images look blurry first. Sustained over-voltage can crack glass or burn the photocathode [Elektroda, Krzysztof Kamienski, #18025015]. AlekZ warns that a spike may destroy the transducer outright [Elektroda, AlekZ, post #18030177]
Are PNW-57 and NS-71 tubes interchangeable?
Yes. WEI-1 tubes from a PNW-57 can replace a failed NS-71 unit, provided wear levels match; mismatched gains hurt image quality [Elektroda, harrymx1, post #18968552]
How do I measure 15 kV safely with a normal multimeter?
Build a 1000 : 1 probe: series-chain ten 10 MΩ 1 W resistors rated 500 V each. Clip probe before power-up, then read millivolts; 15 V reading equals 15 kV. Keep each resistor at least 10 mm apart to stop corona [Elektroda, jta, #18862395].
My original inverter arcs—why, and how do I fix it?
Cracked silicone or dust created a sharp edge; at only 3 V input the arc appears [Elektroda, NiclasLindner, post #18862009] Scrape burnt paths, clean board, re-pot with high-voltage silicone gel rated ≥25 kV/mm [Elektroda, Krzysztof Kamienski, #18862227].
Quick 3-step guide to adding more multiplier stages?
- Add one 27 pF / 3 kV cap and one 5 kV diode per extra stage.
- Maintain capacitor-to-diode orientation identical to the previous stage.
- Re-check output; each stage raises peak DC by the AC input amplitude [Elektroda, krakowmichal, post #15028993]
Can I drive the stock transformer with an NE555?
Yes. Set NE555 as astable at 20 – 30 kHz, 50 % duty. Use a power BJT or logic-level MOSFET plus snubber across primary. dj_volt revived a dead PNW-2 this way [Elektroda, dj_volt, post #15045636]
Where can I buy a ready-made mini converter?
Search AliExpress for “CCFL inverter 3–6 V input”. Modules cost ≈ US $3 and deliver 4 kV AC; just add the doubler [Elektroda, Krzysztof Kamienski, #17963257]. Polish sellers often list pre-built 9 V units on OLX [Elektroda, harrymx1, post #20883787]
What is the purpose of the shielded HV cable?
The inner core carries +14–19 kV; the braid is ground, forming a coax that keeps stray fields away from optics and your hands [Elektroda, Mcrash, post #20880714]
Is it safe to run the converter on 12 V instead of 6 V?
No. Doubling input doubles flyback energy and can punch through aged silicone, causing shorted tracks and smoke [Elektroda, NiclasLindner, #18862344; Elektroda, jta, #18861941]. Limit supply to 6 V or redesign the transformer.
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I have no idea what frequency and filling to apply - I will improvise 
. The night vision lamp has a power supply, as far as I remember, about 9kV. And there is one problem here ... such a lamp (image intensifier) has an electron lens inside. The focal length of this lens is strictly dependent on the applied voltage, so you probably won't destroy the lamp, but you may have a blurry, blurred image.
