Most MAX1771 designs are remarkably similar - whilst failure is rarae, its generally down to a few possibilities...
- The MAX1771 failed and is keeping the FET on, which cooks it as the current limit resistor (if used) with be ignored. This will also cook the inductor. - The FET fails with D-S short. Similar symptoms to the first mode - The supply, if designed and running properly, should not be capable of being overloaded - it has a current limiting resistor. - The inductor has an internal short (rare failure mode). - The inductor has been replaced with one whose maximum DC current is too low - for most nixie PSUs, at least 1A capacity is required - For some reason, there is high frequency parasitic oscillation in the PSU - MAX1771 designs normally run at about 60kHz - if the thing has parasitic oscillation (typically in the MHz region), the FET will cook. Have a look at my MAX1771 page ( http://www.desmith.net/NMdS/Electronics/NixiePSU.html) for pretty much all you need to know about them along with recommended components. Nick -- 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/09a16901-8979-4ca1-a260-5f1ab2f661f2%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
