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Where To Get Sets and Parts For discussions about swapmeets, rallies, NVCF and BVWS, car boot sales, antique and charity shops, dealers, newspaper adverts, the local tip and just about any other source of equipment (other than eBay). |
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28th Jul 2020, 10:59 am | #1 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,397
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EHT Inverter possibility
Whilst recently researching a spread of possible solutions to what is probably a familiar quandary here (demise of oscilloscope EHT gubbins), I found that a variety of auction site sellers offer what appears to be a version of the classic simple HF power oscillator and step-up transformer. This alleges to provide 15kV of what is presumably un-regulated, near-sinusoidal HF AC from a transformer with six secondary bobbin sections- offering the possibility of modding to one or more EHT rails in multiples of 2.5kV (pre-rectification) per section. The nominal supply is 4V DC with a claim of up to 12V capability with a tweak of base bias resistor- that implies that something like a ubiquitous little 5V SMPS could be used to get an old 'scope/monochrome telly into some sort of action if, say, investigating first light before further expenditure of money and effort, not to mention a bit less hazard than mains EHT.
Without wishing to promote a particular seller, phrasing along the lines "15kV inverter" throws up a spread of options. The price is low enough that it could be considered as the basis of something with added feedback regulation, or simply as a core and sectioned/highly isolated bobbin for customising. Tempted to get one myself as a diagnosis tool. Hope this is of use to someone! Plus, I'm assuming that folk here are aware of the hazards of this sort of thing without an exhaustive disclaimer.... Colin |
28th Jul 2020, 6:13 pm | #2 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,820
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Re: EHT Inverter possibility
I might get a couple of these, could be fun! I’ve got a knackered scope tube with O/C heater that I fancy trying to weld the heater in, I’ve tried previously with lower power inverters, but had no success.
Regards Lloyd |
28th Jul 2020, 7:22 pm | #3 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,397
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Re: EHT Inverter possibility
It certainly comes into the "no harm in trying, and little to lose" category. Looking into the spec, I think (hope?) that the output capability is 0.4mA as opposed to the stated 0.4A, otherwise Blofeld and the Pentagon will be hoovering them up.... At least for the sake of the little anonymous TO126 driver device pictured.
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