*Power supply voltage ?* If the supply voltage is higher, it will likely cause more inductor/transformer current, and perhaps enough to cause saturation, which leads to heating.
I've noticed a similar problem with my wristwatch. Even though I have voltage-feedback from the HVDC supply, the current in my transformer increases at higher battery voltages, and it definitely heats-up faster at higher supply voltage. My MOSFET does *not* heat up because it's a very low Rds on device and it's only switching for a few seconds while the time is displayed. ----------------------------------------------- *Load current ?* As mentioned elsewhere the display board is separate, so if it's possible to swap boards with a 'known-good' clock you can quickly narrow-down the problem. Again, I've noticed with my watch that when running fewer segments on the display, the reduced load current effectively reduces the duty-cycle on my HVDC converter, so the transformer heats less. There's no heating at all when the display is dark. It may be that when the board tests-out OK, it's with a lower load-current due to smaller nixies, and/or lower supply voltage. .................................................................................................................................................................. BTW, I still call it a nixie watch even though it uses a 3-1/2 digit panaplex display....who's heard of a panaplex watch? I'll post another picture as soon as I get a decent watchband attached to the case. Although I could fix the transformer-heating problem with a larger transformer, I'm stuck with the pea-sized transformer I have because of size constraints. The wasted energy (heat) apparently isn't a major problem because my demo-board has been running almost 3 months since the last time it was charged. -- 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 [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/7a760b4e-68ba-4a7e-a6a6-d26762b62aee%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
