I was just having a look at the manual for the clock, and was thinking that the adjustable trimpot at R26 should also be checked. Being it is adjustable, could it be that it may have failed somehow? Just a thought.
Ron On Saturday, March 28, 2015 at 7:55:48 AM UTC-4, Kiran Otter wrote: > > Hi folks, glad to find this group! > > I've had a Tubehobby clock for several years, the NCV2.1 with the IN-18 > tubes. In the past Jonas has helped, and I even shipped him the main board > for him to repair, but he hasn't responded to my last request for help, so > I thought I would ask here. > > Recently, I started to notice that other digits in the tubes were > partially lighting up, and eventually the fuse blew. My assumption was > that the K155ID1 drivers had started to go, so I ordered six of them off > eBay, and tried replacing them.. which isn't hard, everything is socketed. > Well it didn't help, so I contacted Jonas. Jonas suggested replacing C6, > which I did and it appeared to fix the problem. > > Maybe a month later, I started to notice the left most digit was faintly > showing numbers, and seemed to be influenced by the next to right digit. > So I thought perhaps the drivers I got from eBay weren't good, so I swapped > them around, trying to see if it made any difference. Unfortunately, I > trashed the two original driver chips that came with the kit. So far > swapping the drivers around among the six I have, hasn't changed anything.. > or if it has, the digits lighting that shouldn't be have moved from tube to > tube. > > Well I let the clock run like this for a week or so, and one day I just > happened to feel around the voltage regulator U1 (L7805CV).. and it's > blazing hot. I put a temp probe on it and it's running at 140F in open air, > and when I built the clock, I epoxied a heatsink to it. It never ever used > to get this hot. In fact the clock has run for years in a closed enclosure > with very little ventilation. It just never produced much heat at all. I > swapped both driver chips for two others, and it still gets just as hot. > > When the clock shuts off the display at night, the temp drops to just > above room temperature. > > So my guess is has to be one of two things I replaced; C6, or the driver > chips. I think it's the drivers, and I'd like to get a pair from somewhere > reputable so I can at least rule them out as the problem. I've seen some > that appear to be ceramic, instead of plastic cased.. claimed to be > 'milspec' but I donno if that's BS or what. > > Any help is appreciated! > > Kiran > > > > > -- 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/f6ee8b94-d609-4d74-8d03-cff12238b0d0%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
