@gregebert - My FLW design is direct drive and utilises the original 'Cinch' sockets to hold the tubes.
- Richard On Friday, 25 July 2025 at 05:22:43 UTC+1 Richard Scales wrote: > Interesting - and helpful - perhaps there was some other issue with it but > replacing it fixed the 'all segments illuminated' issue - it's now been > running non stop for a couple of days - all good. > > So suddenly I have three 4LW clocks, one by Raymond Weisling, one by Pete > Hand and one be me!! > > Whilst I appreciate there is lots of history behind those first two - I > already have too many clocks and wonder if anyone out there has a need that > is greater than mine - I am open to offers on both the Raymond and Pete's > clocks - both without tubes. > > Please send PM if interested. > > - Richard > > On Thursday, 24 July 2025 at 15:49:10 UTC+1 gregebert wrote: > >> I looked at the HV5812 datasheet, and I see that it is only rated for use >> as a VFD driver up to 80 volts. As long as the VPP pin is properly clamped >> so that it wont exceed 80 volts it should be OK to use it for nixie tubes, >> but you will need to make sure the anode supply isn't too high, otherwise >> you run the risk of ghosting or faint glowing of the cathodes when they >> should be off. I'll spare everyone of my rant against multiplexing when >> direct-drive is possible. >> >> It is very possible to measure finite resistance from cathodes to ground >> because the HV5812 has diode-clamped outputs. What you are measuring is the >> resistance thru that diode, into the VPP supply, and from there to ground. >> Most likely there is a bleeder resistor for the +80V (or whatever Pete >> uses) to GND. >> >> >> >> On Wednesday, July 23, 2025 at 10:52:39 PM UTC-7 Richard Scales wrote: >> >>> Update: >>> >>> The two major faults were that the left hand two tubes did not light and >>> one segment was 'missing' on all tubes. >>> >>> Both these issues were 'fixed' by circumventing failed PCB traces with >>> wire. >>> >>> Then the secondary issue of all segments lighting was ultimately >>> resolved by replacing the HV5812 driver. >>> >>> Now I have a working Pete Hand 4LW clock in case! >>> >>> - Richard >>> >>> >>> On Tuesday, 22 July 2025 at 07:33:41 UTC+1 Richard Scales wrote: >>> >>>> >>>> [image: PH1.jpg] >>>> This shows the area where there is a break in the HV supply between the >>>> two sides of the board >>>> [image: PH2.jpg] >>>> >>>> There was no connection between the two pins ringed in yellow. >>>> >>>> [image: PH3.jpg] >>>> >>>> I think this is displaying TE?E though I could be very wrong? >>>> >>>> - Richard >>>> >>>> >>>> On Tuesday, 22 July 2025 at 07:26:40 UTC+1 Richard Scales wrote: >>>> >>>>> I am just looking at an FW4-RI rev B board from Pete Hand. It as >>>>> clearly had some liquid spilt on the tube side of the PCB and was only >>>>> lighting the two tubes on the RHS and then in a very odd manner. >>>>> After a good scrub with some Isopropyl alcohol I started to >>>>> investigate and, thanks to the relative simplicity of the multiplexed >>>>> design I was soon able to deduce two obvious faults. >>>>> One being that there was a break in the PCB trace for one of the >>>>> cathodes. The other being that there was a break in the PCB trace that >>>>> connected the HV from one set of high-sided drivers to the other. >>>>> I 'fixed' these two breaks using wire links for now and that certainly >>>>> restored the operation of the two previously non functional tubes. >>>>> The remaining problem is that all segments on all tubes are >>>>> illuminated dimly whilst it is also possible to discern correct word >>>>> display on all 4 tubes if you really concentrate. >>>>> All cathodes have between 80K and 90K resistance to ground and I am >>>>> assuming that this is the reason for the partial illumination of all >>>>> segments. Though I also note that all the traces from the cathodes to the >>>>> HV driver via the relevant series resistors is on the clean/underside of >>>>> the PCB where I see no evidence of any damage. >>>>> My questions (at this stage!) are based on my assumption that there >>>>> should be an infinite resistance between un-used cathodes and ground. I >>>>> have never used an HV5812 though am familiar with the HV55XX and HV56XX >>>>> range. >>>>> Is this a 'common' fault on these boards? >>>>> Is this a feature of the HV5812 (I am guessing NOT)? >>>>> As the resistance between all cathodes and ground is between 80K and >>>>> 90K - I am assuming that this is a fault at the driver level and not >>>>> some >>>>> more failed traces between the cathodes on all tubes. >>>>> What kind of interest is there in these boards? >>>>> All pointers gleefully received! >>>>> - Richard >>>>> >>>> -- 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 view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/30e41ee5-bb57-416d-a45e-454f123036d7n%40googlegroups.com.
