> The temperature problem is a good clue; there must be a larger transistor > not shown in the schematic that is the actual driver, and I suspect it's > overheating. Does it have a heatsink, and does it get warm/hot ? >
One moment. Heat was in the environment while the whole thing was at rest: we were away on holidays and the circuit was without batteries! Nevertheless there is no larger transistor, just one SMD "3D" (BC856? PNP) for each "EL line" (12 in total). Their emitters all tied to ground. The circuit has three groups of 4 electroluminescent areas (that's more a flat panel than wire, but it is all hidden out of sight in the commercial product). The "common out" is 350 Vpk sine with 400 us period (2500 Hz). Those 12x PNPs collectors pull "cathodes" to ground one at a time. The "common out" doesn't weaken or change frequency. > > Does the supply work correctly when illuminating shorter segments of EL > wire ? > No. And it looks it is getting worse and worse the more I keep it running with my tests! > > The transistors shown in the schematic are probably pre-drivers. They > *should* continue to operate correctly even as the EL wire starts to dim. > You can confirm this with your scope. > Confirmed. Unfortunately I do not have other HV AC equipment, so I am stuck. All I can do is replace the SS8550 and M28S in case they have failed for some reason, but I am mostly sure that is not the solution. My daughter won't be happy, neither will I. Paolo -- 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+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CABj2VaaJA0Mk6nX2t1Tf1B%3DR8WwokuMx7NGH3u7aTEf28txTVg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
