Hi Folks. I did have a poke at the board and the ghosting was apparently caused by a flaky K155ID1 as replacement of it made the problem disappear. However, when operating with my IN18 display board I didn't notice any heating issues, but Kiran still did when I returned the board to him and was using his display board (for those not familiar with the Tubehobby design, the board with the tubes can be removed from the driver board below...it's used with either IN14's or IN18's depending on what anode resistors you put in the driver board). He blew a couple of fuses and noted the Mosfet getting pretty hot again. Pretty much the only thing I didn't swap out was the TL494 as per Ian's comment....so now I'm curious...
On Mon, May 11, 2015 at 6:28 AM, Niek <[email protected]> wrote: > Hi Kiran, > > Did Nick already have a chance to look at your clock? Any idea what was > causing the issues? > > Curious! :) > > > > On Saturday, March 28, 2015 at 12:55:48 PM UTC+1, 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 [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/8e5b2d8d-7254-4549-b8db-11f2abeaef60%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/8e5b2d8d-7254-4549-b8db-11f2abeaef60%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- 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/CAOX%2BRHKCrZgBt%3DYth97NFuqSBrypmqxj-CECAEX9UkhozbqD3Q%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
