- VFD failure? - 6 Updates
- Lead-free solder is such a PITA (rant/whinge) - 4 Updates
| frank <frank@invalid.net>: Sep 07 12:09PM > Just a WAG, but perhaps in normal operation the dim digits were constantly > lit, while the bright ones weren't? could be, but I doubt it. The brightness starts going down from digit 10 and it is really progressive, each digit is dimmer than the one on its left. Things without a schematic are difficult sometimes. What really puzzled me is the fact that swapping the filament pins didn't make any difference. I would suspect the driver (Rockwell 10937), but grid waveforms look all the same. Frank |
| JW <none@dev.null>: Sep 07 08:24AM -0400 On Wed, 7 Sep 2016 12:09:50 +0000 (UTC) frank <frank@invalid.net> wrote in >What really puzzled me is the fact that swapping the filament pins didn't >make any difference. I would suspect the driver (Rockwell 10937), but >grid waveforms look all the same. Interesting. Under a bright light can you see if the phosphor for each digit incrementally looks darker for the dimmer digits? I've never seen that fault before, but I have noticed that when VFDs get dim the phosphor looks darker than a new one. |
| frank <frank@invalid.net>: Sep 07 12:38PM > Message id: <nqp02b$2qn$1@usenet.itgate.net>: > Interesting. Under a bright light can you see if the phosphor for each > digit incrementally looks darker for the dimmer digits? The phosphor looks identical on all digits, as far as I can tell. I'm going to try to swap the last and first grid connection, that should give me some more hints (I hope). Frank |
| frank <frank@invalid.net>: Sep 07 01:16PM > I'm going to try to swap the last and first grid connection, that should > give me some more hints (I hope). swapping the grids leave the bad digits at the same physical place, of course the displayed characters swap too. This is another point in favour of bad VFD, which is unobtanium anyway, it's a futaba 16-SY-03Z. Frank |
| JW <none@dev.null>: Sep 07 11:09AM -0400 On Wed, 7 Sep 2016 13:16:38 +0000 (UTC) frank <frank@invalid.net> wrote in >course the displayed characters swap too. >This is another point in favour of bad VFD, which is unobtanium anyway, >it's a futaba 16-SY-03Z. I think you're right. That's a real weird failure mode, though. Not unobtanium. http://www.plccenter.com/en-US/Buy/FUTABA/16SY03Z but ridiculousium. Any reason you can't move to a newer programmer? You're not programming 2708s or anything? |
| frank <frank@invalid.net>: Sep 07 03:28PM > http://www.plccenter.com/en-US/Buy/FUTABA/16SY03Z > but ridiculousium. yeah, the programmer costs much less > Any reason you can't move to a newer programmer? You're not programming > 2708s or anything? Actually I'm programming a lot of old things, including MCM68764, 2716, most of the MCUs that this old programmer supports... You would be surprised to discover how few programmers support (correctly) the 2532s and MCM6876x (or ricoh pin compatible parts) for example. Anyway... I can live with a magnifying glass for the moment. Frank |
| pedro <me@privacy.net>: Sep 07 07:48PM +0800 Have a gas wall oven with two supply gas valves/solenoids in series - safeguard against one sticking open, one presumes. Coils are connected in parallel. These are situated on TOP of (doh!) the oven shell - not the brightest move but placed there no doubt for service access - tick. Original coils were by Goyen Controls, and lasted 20 years before one failed. By then Tyco had moved in (TYCO=TakeYourCompanyOver). Tyco replacement lasted about 18 months,during which time the other Goyen coil died. Ever since, the Tyco replacements (at ~$A70 each) have lasted about 18 months. It transpires that about the time I got the first Tyco coils, they had transitioned the Oz factory to ROHS. Now these coils are 240VAC so the winding wire is as fine as all getout. How is it terminated? Ah, it is SOLDERED to 1/4" QC/Faston terminals which protrude out through the epoxy/"thermoplastic" former. Evidently thermal cycling is causing solder joint failures, but the necessary surgery with a Dremel to reach the joint would - apart from compromising the overall integrity and insulation characteristics - probably take out untold turns of the coil itself, rendering the operation pointless. |
| pedro <me@privacy.net>: Sep 07 07:53PM +0800 On Wed, 07 Sep 2016 19:48:21 +0800, pedro <me@privacy.net> wrote: I should add that coil failure mode is open cct when hot - as in, half-way through cooking a meal - and continuity returns when cooled to near room temperature. Also that replacing the wall oven comes with a penalty of having to carry out significant kitchen mods. Grrrr! |
| "pfjw@aol.com" <pfjw@aol.com>: Sep 07 06:12AM -0700 On Wednesday, September 7, 2016 at 7:53:21 AM UTC-4, pedro wrote: > to near room temperature. Also that replacing the wall oven comes > with a penalty of having to carry out significant kitchen mods. > Grrrr! And why it is that when we built our summer house, we went to Propane for heat, hot water & cooking. More costly than electric appliances, for sure. But we have NEVER had an issue with appliance failure - apart from two floods that finally took out the refrigerator. The house is now elevated, so that will no longer be an issue. Peter Wieck Melrose Park, PA |
| pedro <me@privacy.net>: Sep 07 11:05PM +0800 On Wed, 7 Sep 2016 06:12:08 -0700 (PDT), "pfjw@aol.com" <pfjw@aol.com> wrote: >And why it is that when we built our summer house, we went to Propane for heat, hot water & cooking. Grid independence, I'm sure. We went with gas because the power system here was flakey and could go out for hours at a time. Our gas hotplates have one 'D' cell providing ignition, while the wall oven does require AC for the igniter/flame-monitor/gas-control (BUT that's all able to be jury rigged off a PC UPS in about a minute flat) so cooking during a blackout is a non-event. |
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