Just to re-iterate - solder a small 100nF capacitor between pins 1 & 2, and another between pins 3 & 2, preferably on the underside of the PCB directly to the 7805's solder pads.
The symptoms you are seeing are almost certainly nothing to do with the heatsinks etc - I'd put good money on this being a very common & classic issue with 78xx & 79xx linear regulators whereby they break into VHF oscillation and over-heat. This is extremely well documented and the manufacturer's datasheets all say that the two suppression caps are not a "nice to have" but are essential. Most of the datasheets actually specify a 330nF input capacitor (between pins 1 & 2) but a 100nF works well too. 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 [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/cea40ec2-1d9a-4bcf-b0f9-b6f1562ac8a6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
